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1. 36 Ad Unlity programs A e D ei e i el wl a ae A 37 Pie A ISCEOLMIES 2 oa BI E BA a we A A A we E 37 AZ Plotof temperamres os aia a eR A eet a ew a e e 38 A 4 3 Signal to Noise Ratio o es 38 A 4 4 Spectrograph foc s test s os sa oc o ee 38 AAS Systenpeiiciency test sa ai gee ade gd Se he a a EE 38 A 4 6 Radial Velocities by Cross Correlation ooo e e ee 38 On line DRS filename conventions 41 Data Archiving 46 The FEROS FITS header 47 Acknowledgements 53 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 This page was intentionally left blank vii Chapter 1 Introduction 1 1 On the contents of the FEROS User Manual The current version of the FEROS User Manual is available as a retrievable postscript file from the ESO home page on the World Wide Web http www 1s eso org lasilla sciops 2p2 E2p2M FEROS Before the observing proposal application deadlines the User Manual is normally updated any significant changes are announced on the FEROS webpages If you have no access to the WWW a printed copy can be requested from ESO s Visiting Astronomers Section on Internet visas eso org in Garching Germany Paper copies of a new version of the FEROS User Manual are printed out only after a major revision of the document The reader is referred to the web version of this document for the best quality of the included color figures The first Chapter of this manual is addr
2. CH 2 FOCU LEN 8 009 FOCU SCALE 11 650 FOCU VALUE 22664 000 GEDELEV 2335 GEOLAT 29 2543 GEOLON 70 7346 ID v 3 38 MOON DEC 3 07020 MOON RA 11 757354 OPER F Labrana TRAK RATEA 15 000000 TRAK RATED 0 000000 Temperature 0 004714 14 57 TEMP6 g 16 750000 16 723333 16 710000 Temperature 0 018856 16 75 ESO VLT DIC 684 20 H 163677 UNKNOWN 51020 UNKNOWN LSO MAN ESO 22200 0001 5 Temperature sensor name RMS of samples over exposure Temperature sensor numeric value Temperature sensor ID Maximum value C Average value C Minimum value C 6 Temperature sensor name RMS of samples over exposure Temperature sensor numeric value OBS OBS Dictionary Expected execution time linked blocks Observation block ID 200 SolarSpectrum norm OB name Observer Name ESO internal PI COI ID PI COI name 60 A 9120 B ESO program identification 2004 07 08T21 23 01 OB start time SolarSpectrum OB target name 2 Template number within OB FEROS_ech_obs_objsky Data File Name Fiber currently used SKY or OBJ Airmass at end Airmass at start Observatory Seeing queried from AS Observatory Seeing queried from AS Observatory ambient air pressure q Observatory ambient air pressure q Observatory ambient relative humi Observatory ambient temperature qu Observatory ambie
3. Image slicer This device converts a two dimensional image e g of a star in the focal plane of the telescope into a one dimensional slit In this way the light that normally would fall outside the slit especially when using a narrow slit for high spectral resolution is fed to the spectrograph Maintenance Technical procedures developed to control and maintain the quality of telescope instrument and detector Mode Selector Unit in the pre fibrehead area of FEROS which can direct calibration light into one of the fibres Observation Block A logical unit of exposures needed to obtain a coherent set of data Encompasses all relevant information for a successful data acquisition on a target It consists of target information a set of templates parameter files for the templates conditions requirements and comments concerning the specified observations It represents the entity the short term scheduler deals with Constructing Observation Blocks is part of the Phase II Proposal Preparation Process Phase II Proposal Preparation P2PP During this phase the successful applicant whose Phase I proposal has been accepted based on the scientific rationale and technical feasibility prepares the Observation Blocks to carry out the observing program Sequencer A sequence of exposures on different targets i e different OBs can be obtained using the Sequencer or Scheduler The Sequencer is capable of conditional branching and has knowledg
4. 41 The FEROS Calibration Plan ic aca A das ea asa a da Re ek a EE e e 42 The FEROS calibration gt cio we EN E a ee 4 3 Calibration in wavelength ooo copos rai ee ee a ee ea e Wa EIC coria Sed DS Seeks Paka wad Bodom wh ood Bald a waned vi a COS FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 45 o e o oe ede ee a ee ad ee 27 4 6 Flux standard star observations 27 4 Quality Contool cs ee Ee a AA ae a 28 ka Special calibrations 1 Gok we ald A E OA A a ee 28 SGA Wetector A 28 Observing 29 5 1 Before the observing nights preparation of OBs o o 0000008 29 52 Dunne the MEM ee a A woe RA AAA ee AS ed A 29 2A TArreLACQUISTIO e a a ie EE EN E ia A ae E 29 2 2 2 Monitoring The integration e ew E EN E EE EN EN E EE 30 5 2 3 Evaluation of the results off line data analysis 30 The reduction of FEROS data 31 6 1 Real Time Display and quick look concordia aena 31 62 Pipeline reduction of FEROS data o c e cdi aos a e aaa a eo a ee d 31 OS Offline data reduction racial ad he a kee a A e 31 Other useful information 33 el Listolstndard stars oc oo EE RO a eee eee Ew aa ae de 33 ea EEN 33 7 3 Pointers to FEROS sample observations 33 Using the DRS pipeline at the telescope 34 Al Startup of MIDAS co escono s osaka e eee Rw eee wwe be aS 35 A 2 Initialization of the DRS at the beginning of the night 35 A 3 On line Reduction Options During the Night o o
5. EUROPEAN SOUTHERN OBSERVATORY Organisation Europ enne pour des Recherches Astronomiques dans 1 H misphere Austral Europ ische Organisation f r astronomische Forschung in der s dlichen Hemisph re LA SILLA OBSERVATORY Science Operations FEROS II User Manual Doc No LSO MAN ESO 22200 0001 Issue 1 4 Date July 9 2004 Keywords FEROS II User Manual Prepared for Review INTERNAL USE ONLY Prepared SE os Name Date Signature Approved O ad E os Name Date Signature Released E e ee 11 FEROS II User Manual 1 4 This page was intentionally left blank LSO MAN ESO 22200 0001 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 111 Change Record Issue Rev Date Section Parag affected Reason Initiation Documents Remarks 20 07 2003 Version 1 1 in new format 20 07 2003 First step toward V 2 0 20 07 2003 Removed old irrelevant text July 2004 Completely revised 1v FEROS II User Manual 1 4 This page was intentionally left blank LSO MAN ESO 22200 0001 Contents 1 Introduction 1 1 On the contents of the FEROS User Manual o o e e 1 2 Information available outside this manual o o eee eee 1 3 Capabilities of the Instrument gt lt cos o sa mo ss de 14 FEROS Wim ESO 2 244 ora a E a A A eo TAA Lasila course a Pe ee A e EE e A E Mid A IN 1 5 How to access FEROS sample calibrations and observations o
6. 16 Bibliography lt lt cee Jee WE EE EE E A A o a doe ee Er d Ka AGIOSSHIG e E E EE EEN A a a Ad G 1 8 Abbreviations and Acronyms 2 Instrument Characteristics 2 1 Optocmechatical layout s e s sso odii la A ee ea ee oes Zao Insimment SUDSYSIEMS cia OA Re ae ae Be ae 22 1 The pre fibrehead system osle e se ao a de ee ee be we HP 22 2 e AAA 223 The Fibrehead Viewer CCD 2 2 44 4 6464 da e id ed be 2 2 4 The Scientific CCDs and the associated butter 2 2 The FEROS Calibration Unit ka eo 239 FEROS YELAGOD S so 2 as aa eds a aboye Aa a a A A 2 4 Spectral Coverage Resolution and Overall Efficiency oo 2 5 Instrument Features and Problems to be aware of o o e 254 EEDCome to Dele A 6 i a EE ee e a Ade 3 Preparing the Observations Sul se A II AAN 3 2 FEROS instrument modes and basic choices o oo e e 324 The Objectesky Configuraton o s se sate ee Aaa EEN AN NIE 3 2 2 The Object Calibration Configuration o o o e 33 Introdticing Observation Blocks cocinar a a er 3 4 The FEROS Exposure Time calculator o oo oooooo ee 34 1 Definition of th target EE e a a EEN ew er E 3 5 Target Acquisition and Guiding ENEE NN ca a E EEN EN e 3 6 Computing time overheads for your program Oot SHOCK Re Goo 2 ea he A ee ee RR OSS Sa BS a aa Sad a Sane eS 4 The calibration of FEROS data
7. ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO FEROS II User Manual 1 4 INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS MIRR3 MODE PATH SENS7 SENS7 SENS7 SENS7 SENS7 SENS7 SENS7 SENS8 SENS8 SENS8 SHUT1 SHUT1 SHUT1 SHUT1 SHUT1 SWSIM TEMP1 TEMP1 TEMP1 TEMP1 TEMP1 TEMP1 TEMP1 TEMP2 TEMP2 TEMP2 TEMP2 TEMP2 TEMP2 TEMP2 TEMP3 TEMP3 TEMP3 TEMP3 TEMP3 TEMP3 TEMP3 TEMP4 TEMP4 TEMP4 TEMP4 TEMP4 TEMP4 TEMP4 TEMPS TEMPS TEMPS TEMPS NAME ID MAX MEAN MIN NAME RMS VAL ID NAME VAL ID NAME NO SWSIM TYPE ID MAX MEAN MIN NAME RMS VAL ID MAX MEAN MIN NAME RMS VAL ID MAX MEAN MIN NAME RMS VAL ID MAX MEAN MIN NAME RMS VAL ID MAX MEAN MIN FEROS FEROS DEFAULT HUMI O 13 450000 13 446667 13 440000 Humidity 0 004714 13 450000 LNLY O LN2 level 63 440000 DARK S DARK 2 H e DN OO D o HS D OS O ROR RR OA OA MM A RR OA OA OA A D D RR OA D OA OA OA OA OA AA OA D A D A D A A A A FREE NORMAL 7 TEMP1 2 14 430000 14 430000 14 430000 gt Temperature 0 000000 14 42 TEMP2 14 480000 14 480000 14 480000 Temperature 0 000000 14 48 gt TEMP3 14 790000 14 783333 14 770000 Tem
8. HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO FEROS II User Manual 1 4 DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET BITS CHIP1 CHIP1 CHIP1 CHIP1 CHIP1 CHIP1 CHIP1 CHIP1 CHIP1 CHIP1 CHIP1 CHIP1 CHIPS DATE DEC DID EXP N DATE ID INDEX NAME NX NY PSZX PSZY X XGAP Y YGAP 0 EXP RDTTIME EXP T EXP X FRAM FRAM 1D NAME 0UTi 0UTi 0UTi 0UTi 0UTi OUT1 OUT1 OUT1 OUT1 OUT1 OUT1 OUT1 0UTi OUT1 OUT1 YPE FERTIM ID TYPE CHIP CONAD GAIN ID INDEX NAME NX NY OVSCX OVSCY PRSCX PRSCY RON H H OUTPUTS OUTREF RA READ READ READ READ SHUT SHUT SHUT SHUT CLOCK MODE NFRAM SPEED ID TMCLOS TMOPEN TYPE LSO MAN ESO 22200 0001 16 Bits per pixel readout 03 10 03 Date of installation YYYY MM DD CCD 60 gt Detector chip identification 1 Ch
9. 6000 7000 Wavelength A Figure 2 4 The measured efficiency The raw image is FEROS 2003 11 15T03 46 08 507 fits The spectrum is a 120 sec exposure of the spectrophotometric standard satr HR 718 The blue curve is a polynomial fit to the peak efficiency from each order Each order is joined by a line Chapter 3 Preparing the Observations 3 1 Introduction Before the actual execution of observations several steps have to be taken The preparation of an observ ing program is split in two parts Phase I and Phase II In Phase I the emphasis in the application for ESO observing time is put on the scientific justification and on the technical feasibility of the proposed observa tions In Phase II the successful applicants prepare the detailed instrument set up and observing plan through the completion of so called Observation Blocks Together with the Phase I and Phase II documentation http www eso org observing proposals the information contained in this chapter and in Chap ter 4 provides a guideline for the Phase I and Phase II preparation process for FEROS observations In Chapter 5 information is given for astronomers who come to La Silla to observe with FEROS The preparation process for FEROS programmes can be summarized as follows Phase I e Definition of scientific justification e Choice of instrument mode e Estimate of exposure time to reach the needed S N ratio e Estimate of telescope and instrument overheads Deter
10. CALMIRR1 ID Normal 2 LSO MAN ESO 22200 0001 CCD sw operational mode 1 0 Interval between two successive te 2 of sources active 138 40 Telemetry value at read completion gt CCD 2 ID of telemetry sensor CCD Cold Plate Description of telemetry param 138 40 Telemetry value at read start 140 20 Telemetry value at read completion CCD2 2 ID of telemetry sensor CCD Cold Plate2 Description of telemetry para 140 20 Telemetry value at read start 119 999936 120 0091 120 00000 2148 4096 SCIENCE ECHELLE 0BJ SKY 0 00000 0 0000 OFF 0 000000 0 00000 0 0000 OFF 0 000000 QUT CALMIRR1 NAME CALMIRR1 NO CALMIRR1 TYPE CALMIRR2 ID CALMIRR2 NAME CALMIRR2 NO CALMIRR2 TYPE DATE DID FILT1 ENC FILT1 POS ID LAMP3 SWSIM gt PARK gt PARK gt FREE gt LAMP 1 gt LAMP 1 gt LAMP 2 2 2 2 2 2 2 D 2 1 1 Binning factor along X Binning factor along Y actual subintegration time Dark current time of subintegrations of pixels along X of pixels along Y If T window enabled Lower left pixel in X Lower left pixel in Y user defined subintegration time of windows readout Observation category Observation technique Observation type Telescope desclination deg Position angle at end deg ADC mode Telescope right ascension deg If T function is software simulat Te
11. added Together the three selected templates form an Observation Block that is used to perform the required observation The preparation and editing of Observation Blocks is done with the Phase II proposal preparation software P2PP 8 which successful applicants for observing time can obtain from ESO http www eso org observing p2pp for installation at the astronomer s home institute This soft ware is also available at the observer s station at the VLT Observatory for preparation of the OBs in advance of the observations 9 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 3 4 The FEROS Exposure Time calculator The FEROS Exposure Time Calculator ETC is accessible from the FEROS web pages The ETC models the instrument and detector It is the basic tool for an observer in the planning of an FEROS observation It can be used to compute S N to be expected for the specified target and atmospheric conditions as a function of exposure time 3 4 1 Definition of the target For the input flux distribution to the ETC stellar spectra are assumed One can choose the spectral type from the list OBAFGKM The magnitude in V and E B V of the target and observing conditions phase of the moon FWHM of seeing disc airmass In addition the atmospheric conditions temperature atmospheric pressure and relative humidity CCD prop erties readout noise dark current and full well capacity and telescope properties mirror diameter an
12. because these were not created by photons from the source Calibration Procedures to remove the instrumental signature from the scientific data e g by subtracting BIAS frames and by dividing through the flatfield Camera FEROS has a dioptric camera imaging the dispersed parallel beams on one CCD detector Charge Coupled Device Electronic 2D array detector converting photons into electrons Cross disperser prism An echelle spectrograph contains two dispersive elements in the case of FEROS one grating and one prism The grating is the echelle grating the prism is called the cross disperser prism The cross disperser prism determines the distance between the echelle orders FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 Fibrehead Viewer Simple optics which focus the light reflected by the fibrehead onto a technical CCD detector They are used to center the targets on the fibre and for guiding Flatfield Spectrum obtained from light source with a flat i e without spectral features energy distribution e g a tungsten lamp The registered signal provides information about the response of the detector allowing a determination of the variation in sensitivity from pixel to pixel the echelle order shape the presence of bad columns on the detector etc Grating One of the main light dispersing elements of FEROS is the echelle grating Guide star A point source used for accurate tracking and active control of the telescope mirrors
13. path of Calibrations The prism cross dispersed two beam two slice folded optical path results in a compact physical layout The spectrograph operates in a quasi Littrow mode in a white pupil configuration Baranne 1972 ESO Cern Conference on Large Telescopes The echelle grating is of type R2 with 79 lines mm and a measured blaze angle of 63 24 The camera is dioptric no central obstruction and provide an external focal plane for easy detector interfacing and upgrading during the lifetime of the instrument together with a large field good image quality and high optical transmission The CCD detector format is 2048 x 4096 pixels The direction of the spectral dispersion echelle orders is along the shorter dimension of the CCD The instrument spectral format wavelength coverage etc is always computed for this fixed CCD window setting 2 2 Instrument subsystems This section describes the FEROS subsystems in the order they are encountered along the optical path going from the telescope to the instrument detector It is intended to guide the users in the selection of the opti mal instrument configuration for his her observing program The functionalities of the different subunits are explained and reference is made to their measured performance 2 2 1 The pre fi brehead system The light path Light from the telescope arrives at the FWA M3 where it is reflected upward passing through the ADC if IN to the fibrehead T
14. pixel pixel variations UNBLAZE FEROS rebins the echelle orders to wavelengths REBIN FEROS acording to beforehand determined dispersion coefficients In this step also the barycentric correction is applied merges the echelle orders MERGE FEROS into two 1D spectra named f filenum 1 and f filenum 2 where the spectrum with the ending 1 referes to the spectrum recorded on the object fibre and the spec trum with the ending 2 to the spectrum recorded on the sky calibration fibre This standard reduction is controlled by the FEROS context keywords which can be listed together with their current contents by the command SHOW FEROS and are set with the command SET FEROS key value See below for useful keywords to be used during the observing session A 1 Startup of MIDAS Normally the entire observer s enviroment including the MIDAS session where the FEROS DRS pipeline will be run during the night is started up by the TIO during the daily instruments and telescope startup procedure If a something goes wrong during the night and the MIDAS session or anything else is lost ask the TIO or support astronomer to restart it A 2 Initialization of the DRS at the beginning of the night To use the automatic data reduction as described above the DRS has to be initialized at the beginning of the night For this purpose several flatfield and wavelength calibration exposures have to be taken in the Object Sky mode of FEROS before the beginning of th
15. reproducing the illumination of the pupil of the telescope From the fibrehead the light is then delivered to the spectrograph via the Science fibres see figure 2 1 The FCU currently houses four sources e LAMP1 Wavelength Calibration ThArNe This source consists of a single Thorium cathode Ar gon 10 and Neon 90 filled Juniper lamp e LAMP2 Flat Field Hal Hal This source consists of two Halogen bulbs one 6V 10W Osram Halogen Halo Star bulb providing the red part of the flatfield and one 12V 50W Osram Halogen Xenophot bulb behind a blue filter providing the blue part of the flatfield Light from the two bulbs are combined via a 50 transmission 50 reflection mirror e LAMP3 Wavelength Calibration ThAr Ne This source consists of a Thorium cathode Argon 100 filled Juniper lamp and a 100k ohm 220V Neon bulb Light from the two bulbs are combined via a 50 transmission 50 reflection mirror LAMP4 HFlat Field D gt Hal This source consists of one Deuterium source and one Halogen bulb within a commercially available unit However only the Deuterium lamp is used since the purpose is to provide FF source for the 3 bluest orders for which the flux from LAMP2 is inadequate Due to current hardware limitations only either LAMP1 or LAMP3 can be used at any given moment Switch ing from one to the other requires toggling the simulation states for the two lamps in the ICS panel and a manual change of a cable at the FEROS Room a
16. the Library building just below the hotel which can also be used for electronic mail correspondence with the outside world telnet connection to the home institute access to the World Wide Web text file editing etc Normally a p2pp introduction i e advice on the OB preparation will be given by the support astronomer of the Observatory 5 2 During the night Observations with the FEROS instrument are carried out at the User Station of MPG ESO 2 20 m telescope console located in the RITZ Control Building located between the NTT and ESO 3 60 m telescopes From there all three La Silla telescopes offered to the ESO community and instruments are remotely controlled The telescope and instrument operator TIO carries out the observations and is responsible for the checking that the telescope and isntruments perform correctly the main area of responsibility of the visiting astronomers is the selection of the OBs to be executed based on the sky conditions and on the results of the previous observations The main actions are outlined below 5 2 1 Target acquisition The OB to be executed is loaded to the BOB panel and started The Telescope Control Software TCS reads the target coordinates from the OB and the telescope is pointed Once the telescope has completed the pointing the FEROS Fibrehead Viewer FFHV Camera which images the fibrehead produces an image of the target field 6 x 4 arcmin as reflected by the fibrehead can be used fo
17. to make dome flatfields The two internal lamps provide a well exposed smooth continuum spectra from approximately 400 nm to above the red cutoff of FEROS within reasonably short exposure times see Table 4 2 A deuterium lamp is recommended for the spectral region shortwards of 380 nm despite the emmission lines The reddest orders however suffer from fringing effects for which domeflats can be useful to correct The flatfield spectra provide a good correction of the blaze function of the echelle They are also useful to correct for the pixel to pixel variation in CCD sensitivity as a function of the impinging wavelength of the light and to correct for the structures introduced by imperfections of the fibre geometry fibre function To the FF calibrations applies the same note of caution regarding stability depending on air pressure and temperature mentioned for the wavelength calibration in Chapter 4 2 FF exposures can also be attached to science OBs 4 5 Solar spectra According the the FEROS Calibration Plan every afternoon if not too cloudy approximately 1 hr before sunset two two minute solar spectra are acquired These spectra can be helpful for order tracing in the bluest orders where the Hal4 Hal lamp flux is insufficient 4 6 Flux standard star observations Spectrophotometric standard stars can be used to obtain response curves of the instrument to allow a relative flux calibration of the spectra and at the same time to correct f
18. unbinned 1 port 21 seconds However this readout mode has NOT yet been fully commissioned It should therefore be considered experimental and is offered in Visitor Mode only where it will be the responsibility of the visitor to verify the scientific integrity of the resulting data Calibrations BIAS frames and FF and ThAr calibration lamp exposures are taken during the day for details cf 2 If wavelength accuracy is critical either the OBJCAL mode should be used or a ThAr calibration should be taken immediately after the science exposure This will take into account any significant change in the air pressure or in the air temperature see Chapter 4 2 The same applies to the FF at wavelengths where the effect of fringing is important A gt 650 nm As an example we consider a target where the ETC computes an exposure time of 180 minutes to reach the desired S N ratio and it is required to obtain the highest accuracy in the wavelength calibration and in the FF correction We split the exposure time into three integrations of 1 hour to permit median filtering of the cosmic rays Additionally both FF and wavelength calibrations exposures are attached for high radial velocity accuracy and accurate flatfielding We thus have telescope pointing 360 sec FCU Adapter setup 60 sec 1 exposure 3600 sec read out time 41 sec FCU Adapter setup 60 sec ThAr 10sec read out time 41 sec FCU Adapter setup 10sec LampWarmup 60 sec
19. 194 89131245 2004 07 08T21 23 29 77003 397 42545 347 UNKNOWN UNKNOWN PIXEL PIXEL 7 1 0 1 0 51 0 1 0 1 0 1 0 F 381 Original 395 Standard FITS format NOST 100 0 of bits storing pix values of axes in frame pixels axis pixels axis Number of parameters per group Number of groups pixel FITS BSCALE BZERO pixel FITS BSCALE BZERO European Southern Observatory UT date when this file was written ESO Telescope Name Instrument used target 12 59 59 8 RA J2000 at start in deg 29 59 59 9 DEC J2000 at start in d Standard FK5 years Coordinate reference frame Total integration time MJD start 2004 07 08T21 23 29 396 Date of observation 21 23 23 397 UTC at start sec 11 49 05 347 LST at start sec PI COI name Name of observer D NNNNNNNN 0FF Pixel coordinate system Pixel coordinate system value of ref pixel value of ref pixel Ref pixel of center of rotation Ref pixel of center of rotation Binning factor Binning factor Extension may be present Status of autoguider 0 90000 Position angle at start 47 48 HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH
20. EROS CCD is of good cosmetic quality The number of hot or less sensitive pixels is limited lt 0 1 and has little effect on the quality of the data because of the large sampling The major defects are the several complete or partial bad columns see table 2 2 16 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 Table 2 2 CCD bad columns In the standard application of the FEROS DRS pipeline the entire columns are replaced by the means of the nearest row neighboors of each pixel Row start finish nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnonn FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 Calibration Fibres Th rNe FCU Figure 2 3 Schematic diagram of the FCU 17 18 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 FEROS efficiency test Fibre 1 input files fero9203 mt hr718 UD 25 qT AO A mie 30 15 E Hr A ORT EE D 712 JEJE ETE SSD SEO El EE E Hei API E Ui AA TEA d H ga E en eire aenie eee cicimg v CH Ka D 0 08 AP S 4000 5000
21. F A i i i 1 1 i i 1 4000 6000 8000 Wavelength A Figure 2 2 The relative fibre efficiency in the sense of OBJECT SKY fibre The raw frame is a solar spectrum image FEROS 2003 11 12T22 42 22 906 fits acquired during the November Commissioning Each point represents one of the e chelle orders The Image Slicer TBD See the original FEROS Final Design Report downloadable from http www 1s eso org lasilla sciops 2p2 E2p2M FEROS Documentation fdr ps gz The First Colimator TBD See the original FEROS Final Design Report downloadable from http www 1s eso org lasilla sciops 2p2 E2p2M FEROS Documentation fdr ps gz The chelle Grating TBD See the original FEROS Final Design Report downloadable from http www 1s eso org lasilla sciops 2p2 E2p2M FEROS Documentation fdr ps gz The Flat Folding Mirror TBD See the original FEROS Final Design Report downloadable from http www 1s eso org lasilla sciops 2p2 E2p2M FEROS Documentation fdr ps gz The Second Collimator TBD See the original FEROS Final Design Report downloadable from http www 1s eso org lasilla sciops 2p2 E2p2M FEROS Documentation fdr ps gz The Cross Dispersing Prism TBD See the original FEROS Final Design Report downloadable from http www 1s eso org lasilla sciops 2p2 E2p2M FEROS Documentation fdr ps gz The Camera 12 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 TBD See the original FEROS Final Design Report downloadable from h
22. IERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO INS INS INS INS INS INS INS INS INS INS OBS OBS OBS OBS OBS OBS OBS OBS OBS OBS OBS OBS DCS TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEL TEMPS TEMPS TEMPS TEMP6 TEMP6 TEMP6 TEMP6 TEMP6 TEMP6 TEMP6 DID EXECTIME GRP ID NAME OBSERVER PI COI ID PI COI NAME PROG ID START TARG NAME TPLNO DET1 IMGNAME AG FIBSELEC OBJFIB ATRM END 1 035 AIRM START 1 037 AMBI FWHM END 1 00 AMBI FWHM START 1 00 AMBI PRES END 773 20 AMBI PRES START 773 20 AMBI RHUM 23 AMBI TEMP 12 85 AMBI WINDDIR 278 AMBI WINDSP 3 30 CHOP ST F DATE DID ES0 2P2 DIC DOME STATUS FULLY OPEN FOCU ID
23. IFF 60 sec read out time 41 sec x three times This leads to a total time of 12189 sec or 203 15 m of which 183 5 m is integration and just under 20m is overhead 10 The overhead becomes relatively more important if many short exposures with many attached calibrations are required 3 7 Check list 1 Decide whether to OBJSKY or OBJCAL mode 2 Decide for visitor justification needed or service mode 3 Use ETC to check exposure time 4 Any special constraints needed time critical observations etc 5 Define calibration needs exceeding the standard calibrations as defined in the calibration plan 6 Compute time to be requested including overheads Chapter 4 The calibration of FEROS data 4 1 The FEROS Calibration Plan The observatory s calibration strategy for the FEROS instrument is described in detail in the FEROS Calibra tion Plan cf 2 available from TBD and summarised at http www 1s eso org lasilla sciops 2p2 E2p2M FEROS CalPlan Table 4 1 provides a summary of the current calibration plan for scientific FEROS data All daily calibrations are defined and executed in a fully automatic procedure according to the science data obtained in the previous night The same calibrations are applicable for both OBJSKY and OBJCAL mode If additional calibrations are needed the corresponding Observation Blocks have to be provided by the Visitor observer or the Service mode PI using the data and instructions provided
24. MAN ESO 22200 0001 FilenameFF filenum ext2 bdf Keyword RAW_IMG FLAT_IMG Content Extracted flatfield orders of sky fibre Format position mm order Filename ThAr filenum bdf Keyword WLC_IMG Content average calibration frame from catalogue ThAr cat filenum is taken from the first file in the catalogue Format position mm position mm Filename ThAr filenum ext1 bdf Keyword WLC_IMG Content Extracted calibration orders of object fibre Format position mm order Filename ThAr filenum ext2 bdf Keyword WLC_IMG Content Extracted calibration orders of sky fibre Format position mm order Filename ThAr filenum lines1 bdf Keyword LINE_POS_TBL Content Table with found calibration lines of object fibre order by order dispersion coefficients are stored in the descriptor DCOEF D 1 195 with 5 polynomial coefficients per order used for rebin ning Saved to ThAr filenum _LINE1 tbl by SAVE FEROS ThAr filenum Format MIDAS table Filename ThAr filenum lines2 bdf Keyword LINE_POS_TBL Content Table with found calibration lines of sky fibre order by order dispersion coefficients are stored in the descriptor DCOEF D 1 195 with 5 polynomial coefficients per order used for rebinning Saved to ThAr filenum _LINE 2 tbl by SAVE FEROS ThAr filenum Format MIDAS table Filename ThAr filenum _INIT bdf Content Table with session keywords in descriptors session keywords and defaults in table rows Session keywords
25. ad should not exceed a peak to peak of 0 02 Angstroms The session parameters are saved as session WLC IMG With this step completed the FEROS on line DRS is initialized Every new incoming spectrum will be saved and reduced now as described above A 3 On line Reduction Options During the Night The context keywords allow to control the parameters of the reduction process The keywords can be listed to gether with their current contents by the command SHOW FEROS and are set with the command SET FEROS FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 37 key value Alternatively the keywords can be set using the FEROS GUI which is started by the command CREATE GUI feros If the keywords are set to new values they will only affect the automatic on line DRS for next incoming files If one of the files already transfered to the IWS fero filenum mt should be reduced again according to the new settings of the keywords this is easily achieved by re starting the autoreduce command manually as follows autoreduce fero filenum Useful keywords for the observing session might be 1 EXT_MODE controls the method used for the extraction of the spectra The three options are SET FEROS EXT_MODESS the standard extraction is performed where the flux across the slit is ust summed SET FEROS EXT_MODE M the standard extraction is performed as above but with clipping of cosmics SET FEROS EXT_MODE O the optimum extraction is perf
26. and Overall Effi ciency The user can only affect the spectral resolution by the choice to some extent by binning the CCD The factors outside his her control which affect the resolving power are the diameters of the SCIENCE fibres the number of slices created by the image slicers 2 image quality of the optics including the focus and the alignment CCD effects chip tilt diffusion of photoelectrons charge transfer as well as the echelle dispersion The instrument does not include a remotely controlled focus adjustment since the camera automatically compen sates for temperature variations within the instrument enclosure The image quality over the entire spectral range is expected to be better than TBD um over the full CCD 80 of the energy This allows to reach the maximum resolving power two pixel sampling By the use of the two slice image slicer the resolving power of FEROS is 48 000 with a degradation less than 10 over the whole wavelength range Recent measurements of the resolving power and other instrument characteristics are available under TBD The individual transmission and reflection efficiency curves of the various optical components and of the CCD and the combined overall efficiencies are tabulated in at http www 1s eso org lasilla sciops 2p2 E2p2M FEROS InstrumentCharacteristics InstrumentEfficiency html The predicted global instrument efficiency is higher than 0 2 from 400 to almost 800 nm With these efficie
27. are restored by command INIT FEROS MIDAS Table Filename template bdf Content Image with cross correlation template for order definition Copied to ThAr filenum TEMPLATE bdf by command INIT FEROS ThAr filenum Format pixels template must be centered to central pixel FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 43 e Filename echpos tbl Keyword GUESS_TBL Content Table with guess for order definition Copied to ThAr filenum GORDER tbl by com mand INIT FEROS ThAr filenum Format MIDAS Table e Filename centers tbl Keyword CENTER_TBL Content Table with order definition Copied to ThAr filenum by command INIT FEROS Format MIDAS table e Filename cop_coeffs1 tbl Keyword COEF_COP Content Table with cross order profile definition of object fibre Copied to ThAr filenum COP1 tbl by command INIT FEROS ThAr filenum Format MIDAS Table e Filename cop_coeffs2 tbl COEF_COP Content Table with cross order profile definition of sky fibre Copied to ThAr filenum COP2 tbl by command INIT FEROS ThAr filenum Format MIDAS Table e Filename wlc_coeffs1 tbl Keyword COEF_WLC Content Table with wavelength calibration coefficients of object fibre from global fit Copied to ThAr filenum _WLC1 tbl by command INIT FEROS ThAr filenum Format MIDAS Table e Filename wlc_coeffs2 tbl Keyword COEF_WLC Content Table with wavelength calibration coefficients of sky fibre from global fit Copied to ThAr filenu
28. c cable with an open close time of 50 ms The illumination of the detectors is homogeneous within 50 ms but a minimum exposure time of 0 5 sec is recommended The reader is referred to the CCD webpages of the ESO Optical Detector Team for additional general information on the CCDs and the Control System FIERA http www eso org odt FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 13 Table 2 1 Measured properties of FEROS scientific CCD July 2004 values Quantum efficiency Number of pixels Pixel size Gain Read out noise Saturation Full frame readout s Dark current levels Fringing amplitude CTE Read out direction Prescan Overscan areas Flatness 50 at 350 nm 58 at 370 nm 72 at 400 nm 85 at 450 nm 85 at 500 nm 85 at 600 nm 78 at 700 nm 55 at 800 nm 28 at 900 nm 2048 x 4096 15 um low 3 2 e ADU high 1 0e ADU fast readout low gain 5 1 e 16 3 ADU rms slow read out high gain 3 0 e7 3 0 ADU rms low gain 40 000 ADU high gain 65 000 ADU low gain unbinned 41 high gain unbinned 148 TBD TBD TBD in disp dir Pix 49 0 and 2049 2098 TBD 14 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 2 2 5 The FEROS Calibration Unit The FEROS Calibration Unit FCU provides flat field and wavelength calibration lamp sources to the spec trograph Light is delivered from the FCU via the Calibration fibres to the adapter where optics image the light onto the fibrehead
29. ce Guide http www ls eso org lasilla sciops 2p2 E2p2M FEROS For checking on possible recent changes in the instrument not yet recorded in the current version of the User Manual consult the FEROS web page at http www 1s eso org lasilla sciops 2p2 E2p2M FEROS Information on the current instrument performance can be found on the FEROS Quality Control pages at http www 1s eso org lasilla sciops 2p2 E2p2M FEROS InstrumentCharacteristics InstrumentEfficiency html 1 3 Capabilities of the Instrument ESO s Fibre fed Extended Range Echelle Spectrograph FEROS is a bench mounted thermally controlled prism crossdispersed echelle spectrograph now installed at the MPG ESO 2 20 m telescope at ESO La Silla It is designed to be a high resolution high efficiency versatile spectrograph providing in a single spectrogram almost complete spectral coverage from 350 920 nm Precise radial velocity work accuracies of 25 m s The two spectral ranges 853 4 854 1 nm and 886 2 887 5 nm are lost due to non overlap of the spectral orders FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 3 or better is also possible especially via the Object Calibration mode The spectrograph is fed by two fibres providing simultaneous spectra of object plus either sky or one of the two calibration lamps wavelength calibration and flat field The fibres are illuminated via 2 0 arcsec apertures on the sky separated by 2 9 arcmins A small amount of rotation of
30. d tele scope efficiency must be entered though in most case the default values will be perfectly adequate The final entry is the exposure time The expected Flux from the star the sky the dark current the readout noise and the S N at the approximate wavelengths of the standard UBVRI photometric filters are reported The ETC will also report if the exposure can be expected to surpass the full well capacity of the detector The ETC is accurate except at the bluest wavelengths i e for in terms of the ETC at BVRI but not U in ideal observing conditions i e excellent atmospheric transparency sub arcsec seeing and when the telescope has been well focussed i e when measured efficiencies exceed 18 Therefore in typical conditions when measured efficiencies typically are in the range 10 18 allowance should be made accordingly For Service Mode programmes if a constraint of PHOT of CLEAR conditions is specified it is advisable to multiply the exposure times determined by the ETC by TWO in order to maximise the probablity of achieveing the required S N in typical conditions If you are aiming your FEROS Service Mode programme as a filler programme and are therefore willing to accept THIN to THICK conditions then you should multiply the exposure times determined by the ETC by FOUR in order to maximise the probablity of achieveing the required S N in such conditions conditions however bearing in mid that your OBs always have the chance o
31. e night This is normally taken care of each afternoon by the TIO and or support astronomer according the the FEROS Calibration Plan and is achieved via the execution of one of the Standard Calibration OBs If a visiting astronomer wishes to repeat the initialization personally the basic sequence to follow is e Reset the image catalogues FF cat ThAr cat Dark cat Object cat by the command init reset 36 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 Insert a new write enabled DAT in the drive dev rmt Im Note that this DAT will be overwritten from the beginning erasing any contents One 60m DAT can carry about 70 files If you are to take more than 70 full frames it is advisable to change the DAT right before Use the instrument control software XFCU running on the CCD control PC next to the ISW to turn on the wavelength calibration lamp and use the BIAS CCD control software to take several typical 2 exposures of 15 sec each For details on the XFCU software see here for the BIAS software see here The resulting frames are automatically transfered to the WS and added to the catalogue ThAr cat Switch with the XFCU program to the flatfield lamp and take depending on the S N needed for a appropriate reduction of the planned science exposures 3 to 10 exposures of 30 sec The frames are automatically transfered to the IWS and added to the catalogue PE cat Initialize the DRS for the night with the command init guess where
32. e of parameters not necessarily accessible to the observation software e g the seeing conditions Standard Setting A pre defined setting of the instrument facilitating the preparation of the observations The Observatory keeps an updated database of the relevant calibration files for all Standard Settings of the instrument Template A set of instructions for the performance of a standard operation on an instrument typically an instrument and detector setups The templates represent specially devised sequences for all instrument operations and calibrations Template Signature File This is a description of a Template and its parameters It contains information about the type and allowed ranges of the parameters some of the parameters have to be set by the observer Wavelength calibration Spectrum obtained from a reference emission line lamp The wavelengths of the many emission lines are accurately known and are used to transform pixel space into wavelength space FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 1 8 Abbreviations and Acronyms AT BOB CAL CCD CD ESO ETC EM FCU FEROS FV FWA IS LSO OB OS OBS P2PP RTD SCSM STD SM TSF VLT VM Acquisition Template Broker for Observations Blocks Calibration exposure Charge Coupled Device Crossdisperser European Southern Observatory Exposure Time Calculator Exposure Meter FEROS Calibration Unit Fibre fed Extended Range Echelle Spectrograph Fibrehead Vie
33. een obtained during the FEROS Commissionings in October and December 1999 and in January 2000 They are available as public data from the ESO archive The list is accessible at http www eso org science uves_comm 1 6 Bibliography 1 FEROS II Template Manual 2p2 TRE ESO 22400 0001 version 1 0 09 07 2004 J Pritchard 5 FEROS Pipeline User s Manual Issue 2292 29 2 227 4 FEROS II Commissioning Report 2P2 TRE ESO 22200 0001 version 1 0 J Pritchard 6 FEROS II Instrument Software User Requirements 2p2 SRS ESO 22400 0001 Issue 1 0 20 08 2003 J Pritchard 8 P2PP User s Manual VLT MAN ESO 19200 1644 Version 2 7 12 01 04 F Comer on D Silva 9 FEROS ICS Dictionary ESO VLT DIC FEROS ICS Version 1 2224 22 22 2272 2 229292977 10 CCD DCS Dictionary ESO VLT DIC CCDDCS Version 2 12 17 04 1998 11 FIERA DCS Dictionary ESO VLT DIC FCDDCS Version 2 25 02 04 1998 12 TCS Dictionary ESO VLT DIC TCS Version 1 66 14 04 1998 1 7 Glossary Acquisition Accurate positioning of the telescope in order to center the target on the spectrograph fibre aperture Atmospheric Dispersion Correction ADC unit This unit can be inserted in the pre fibrehead area of FEROS to correct for atmospheric dispersion Not yet implemented BIAS frame Read out of the CCD detector of zero integration time with shutter closed The registered number of electrons per pixel has to be subtracted from a science exposure
34. essed to users who are not familiar with the FEROS instrument and who are interested in a quick overview of its capabilities in comparison with other similar ESO instruments This should enable a potential user to select the best instrument for a given observing program It also includes information on how to access FITS files of reference FEROS spectra and a glossary of terms used in the Manual The second Chapter provides the description of the instrument the instrument layout 82 1 its components 2 2 the properties of the CCD Fibrehead Viewer and of the scientific CCD detector 82 3 2 4 the resolving power and overall efficiency 82 5 and reference to instrument features to be kept in mind while planning the observations or reducing the data 52 6 It can be consulted by users who want to prepare an Observing Proposal Phase I but should definitely be read by those who have been granted observing time and have to prepare their observations Phase II The third Chapter provides the basic information needed to prepare an observing program the identifi cation of the instrument observing modes 83 2 of the standard instrument wavelength settings 83 3 and a description of the Exposure Time Calculator 3 6 The fourth Chapter deals with calibration strategy wavelength flat fielding relative and absolute calibrations of data obtained in standard operation It also outlines calibration techniques for high velocity accuracy and very hi
35. f being executed in better conditions than your constraints it is thus best to break the total exposure into 2 4 individual exposures so as to avoid the posibility of saturation 3 5 Target Acquisition and Guiding The pointing of the MPG ESO 2 20 m telescope is accurate to 5 arcsec rms this does however not guarantee that the target will be centered on the fibre after telescope pointing In case of crowded fields the identification of the object is carried out by the astronomer or in case of service observations with help of a finding chart provided by the user Final coordinates and when required the finding chart in the for mat specified in the Proposal Instructions must be submitted during Phase II of the proposal preparation The target coordinates must be accurate to lt 1 to avoid an unnecessary waste of telescope time dur ing the target acquisition phase In most cases the Digital Sky Survey DSS can be used to prepare find ing charts and is accessible from the ESO world wide webpages http archive eso org dss dss or using Skycat For crowded fields or faint extended objects other well suited image sources have to be used The DSS and other tools can be accessed through the Proposal Preparation and Submission page http www eso org observing proposals which allow the calculation of site sky ephemerides the determination of object observability airmasses etc For the observation of moving targets the acquisi tion te
36. files has to be provided The catalogue names have to entered without the extension cat the result table will carry the name objectcat Example Midas 897 gt read icat 51Peg Image Catalog 51Peg cat No Name Ident Naxis Npix 0001 1212ext1 bdf 2 4102 39 0015 f1417ext1 bdf 2 4102 39 Midas 897 gt read icat 51Pegthar Image Catalog 51Pegthar cat No Name Ident Naxis Npix 0001 1200ext1 bdf 2 4102 39 0015 1410ext1 bdf 2 4102 39 Midas 899 gt 00 radvel 51Peg 1212 51Pegthar 1200 Midas 900 gt plot tab 51Peg jd24 dbc Appendix B On line DRS fi lename conventions init e Filename fero filenum mt Content rawimage in FITS format as transferred to the instrument Format pixel pixel e Filename FF cat Content Catalogue with FLATFIELD exposures Format MIDAS catalogue e Filename ThAr cat Content Catalogue with CALIBRATION exposures Format MIDAS catalogue e Filename Dark cat Content Catalogue with DARK exposures Format MIDAS catalogue e Filename Objects cat Content Catalogue with SCIENCE exposures Format MIDAS catalogue e Filename FF filenum bdf Keyword RAW_IMG Content average flatfield frame from catalogue FF cat filenum is taken from the first file in the catalogue Format position mm position mm e Filename FF filenum extl bdf Keyword RAW_IMG FLAT_IMG Content Extracted flatfield orders of object fibre Format position mm order 41 42 FEROS II User Manual 1 4 LSO
37. g algorithm which analyses the guiding images themselve insures that the reference position of the fibre is always acurrately known and accounts for adapter flexure whioch could cause the apparent position of the fibre to shift on the FFHV In practice however it is found that the FEROS WFI Adapteris very rigid and flexure from one extreme pointing of the telescope to another e g from the maximum western pointing to the maximum eastern pointing is negligable The FFHV image is automatically saved at the end of each acquisition It is included in the observers data package both Service and Visitor mode The FFHV images are NOT archived in the ESO archive due to non DICB compliance of the FFHV image headers 3 6 Computing time overheads for your program By using the FEROS Exposure Time Calculator the user obtains estimates of the observing time needed to reach the desired S N ratio depending on the object magnitude and observing configuration and condisitons In order to arrive to the total observing time in hours or nights required for the program it is necessary to add the time for the various actions related to the scientific observation When applying for service mode observations the computation of the overheads is required and has to be included in the application The current date of this issue of the UM estimate of the overheads is provided below e Telescope pointing target acquisition and centering on fibre Assuming that the tele
38. g designed and this too will be mounted in the FWA The Spectrograph itself is installed in a thermally stabilised room the FEROS Climate Controlled Room CCR located on the level below the observing floor in the 2 20 m telescope building within the so called FEROS Room The optical components are mounted on an 2400 x 1500 x 200 mm Newport M RPR 58 8 optical table There are no movable or remotely controlled components on the optical table except the CCD shutter and the LED CCDTest light ring which can be moved manually and whose three sets of LEDS Red Green amp Blue can be remotely turned on and off Therefore FEROS works in a fixed configuration in order to guarantee the best possible long term stability of the spectrograph The FEROS Calibration Unit FCU is located in the FEROS room It provides flat field and wavelength calibration lamp sources to the spectrograph Light is delivered from the FCU via the CALIBRATION fibres to the FWA where optics image the light onto the fibrehead reproducing the illumination of the pupil of the telescope From the fibrehead the light is then delivered to the spectrograph via the SCIENCE fibres see figure 2 1 All changes between the operational modes are carried out with at the FCU and in the FWA Temperature stability of 0 5 degree celcius is maintained FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 9 Calibration Fibres Science Fibres Fb Adapter FEROS Figure 2 1 Light
39. gh S N ratios The fifth Chapter pro vides information for the visiting astronomers who come to the La Silla Observatory to use FEROS The sixth Chapter summarizes the properties of the pipeline reduction carried out for data obtained using the standard set ups of the instrument 1 2 Information available outside this manual If you cannot find a specific piece of information in the FEROS User Manual or in case you have remaining questions please contact http www eso org observing support html or more specifically e For information on the instrument performance and Phase I and Phase II proposal preparation please contact the User Support Group usg help eso org 2 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 Table 1 1 FEROS characteristics and observing capabilities Wavelength range in one exposure object sky 356 920 nm 39 orders 2 fibres Resolving Power with Fibre Input Output Focal Dioptic Camera OOO OOOO Soo O 2048 x 4096 15 um thinned Detection Efficiency without telescope 7 3 700 A 27 5 000 A 8 9 000 A Limiting Magnitudes at the ESO 2 20 16 7 mag in V S N 15 2 h 13 2 mag in V S N 100 2 h Radial Velocity Accuracy For questions directly related to your granted observing run in Visitor Mode please contact La Silla Science Operations lasilla eso org e For Phase II preparation of Observation Blocks OBs follow the instructions given in the FEROS Template Referen
40. guess is the name of a previously saved guess session Typically this is the session saved in the night before The seesion names are formed automatically from the filenumber of the first calibration exposure in the catalogue ThAr cat and the prefix ThAr e g ThAr0741 Now the following initialization steps are performed Initialization of the session keywords and tables INIT FEROS Averaging of the frames of the respective catalogues FF cat ThAr cat Setting of the CCD gain keyword according to descriptor CCD_GAIN and the values specified in init prg Locating of the echelle orders in the averaged flatfield LOCATE FEROS the fitted positions are shown in the display window Standard reduction of the flatfield BACK FEROS STRAIGHTEN FEROS EXTRACT FEROS The extraction is done twice the first time the cross order profiles are determined for an optimum ex traction with cosmic removal for the science exposures the second time the flatfield orders are extracted The name of the reduced flatfield is found in the keyword FLAT IMG Standard reduction of the wavelength calibration BACK FEROS STRAIGHTEN FEROS EXTRACT FEROS The name of the reduced calibration is found in the keyword WLC_IMG Search for emission lines in the reduced calibration frame FIND FEROS Wavelength calibration by iterative fitting of the dispersion coefficients CALIBRATE FEROS The residuals of the individual lines are plotted over the order number The spre
41. he COPY DAT 38 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 A 4 2 Plot of temperatures A plot and a table with the spectrograph and room temperatures corresponding to the obtained CCD frames can be obtained with the command temperature tablename filenum_start filenum_end where tablename is the name for the output table filenum_start filenum_end are the 4 digit filenumbers of the interval of files to be used In the table also the measured relative humidity is stored and can plotted with the command plo table tablename JD24 RHUM A 4 3 Signal to Noise Ratio After a spectrum fero filenum mt of a science object has been passed the on line DRS the achieved Signal to Noise Ratio SNR can be tentatively measured in a line free region of the spectrum with the following command snr filenum start end fibrenum where the parameters start end determines the wavelength interval to be used for the SNR estimate fibrenum refers to the fibre to be used i e 1 for the object fibre default 2 for the sky fibre Note that the performance of this procedure is heavily affected by sharp spectral features as spectral lines or cosmic ray hits Further the SNR of the used flatfield may limit the SNR measured A 4 4 Spectrograph focus test After a wavelength calibration spectrum fero filenum mt has been taken and the DRS is initialized as de scribed above the command focus filenum reduces the calibration
42. he GIRAFFE long slit spectrograph mounted on the Nasmyth platform The data are collected by a 2048 x 4096 pixels CCD One CCD frame contains the linear spectra of up to 132 objects observed in parallel with a limiting resolving power of 20 000 and a spectral coverage in a single exposure of 26 60 nm depending on the wavelength GIRAFFE is on average 30 less efficient than FEROS but the multiplexing gain can make it the best choice if the observing program includes many objects in a single field at intermediate spectral resolution Spectroscopy at infrared wavelengths 1 5 um Complementary spectroscopic observations at infrared wavelengths can be obtained with two other VLT in struments e The infrared imager spectrometer ISAAC can be used to obtain spectra in the 1 5 um spectral region Two separate cameras in the same cryogenic vacuum vessel are optimized separately for the 1 2 5 um and 2 5 5 um spectral ranges with resolving power up to 10 000 if a 0 5 arcsec slit is used FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 5 e A high resolution infrared spectrometer CRIRES is currently under study It is intended to be the counterpart of UVES in the 1 5 micron spectral region providing a resolution up to 40 000 0 5 arcsec slit in a single order or cross dispersed format 1 5 How to access FEROS sample calibrations and observations A large number of scientific observations of a variety of targets and the associated calibrations have b
43. he fibrehead viewing camera is located directly below the fibrehead Light from the FCU arrives at the FWA via the CALIBRATION fibres It is reflected onto the fibrehead via the SCSM The SCSM and the ADC can NOT be used simultaneously 2Quasi Littrow mode i e with the angle of incidence and diffraction equal but in a different plane to maximize effi ciency 3As of this writing July 9 2004 the ADC is not yet implemented 10 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 The pre fibrehead functions In the converging f 15 beam coming from the telescope the first element is the FWA M3 which allows switching between FEROS and WFI in approximately 8 seconds When IN the M3 obscures the central approximately 40 of the WFI field of view Then follows the ADC The ADC is moved IN and OUT of the beam via an arm The ADC consists of two counter rotating prisms each prism consisting of two elements consisting of UBK7 and LLF6 glass The two glasses are glued together while the air glass surfaces are coated with a broadband Balzers Super Triolin Anti Reflection coating 2 2 2 The spectrograph The light path The two f 8 beams OBJECT and SKY CALIBRATION either from the telescope and or the calibration unit arrive at the fibrehead where they enter the fibre apertures The beams are focussed onto the SCIENCE fibres by rod type microlenses After exiting the SCIENCE fibres it traverses the F N Adaption Lens System the Image Slicer the Fi
44. hould be addressed to the La Silla SciOps Shift Leader lasilla eso org Data Packages for Visitor and Service Mode programmes including raw data DRS Pipeline products FFHV images and relevant log files are provided via CD and or DVD according to taste These CDs are created by La Silla SciOps staff usually either the TIOs or the support astronomers For Visitor Mode programmes the CDs and or DVDs are usually ready for the observer to take home with him her before departing from the observatory normally in the afternoon after the end of the last night of observations For Service Mode programmes data packages are sent via mail to the programme PIs upon completion of the entire set of OBs or the end of the relevant ESO period whichever comes first Typically one night of FEROS observations plus calibrations will fill one CD raw data being gzipped 46 Appendix D The FEROS FITS header SIMPLE BITPIX NAXIS NAXIS1 NAXIS2 PCOUNT GCOUNT BZERO BSCALE ORIGIN DATE TELESCOP INSTRUME OBJECT RA DEC EQUINOX RADECSYS EXPTIME MJD OBS DATE OBS UTC LST PI COI OBSERVER CTYPE1 CTYPE2 CRVAL1 CRVAL2 CRPIX1 CRPIX2 CDELTi CDELT2 EXTEND HIERARCH ESO ADA GUID STATUS HIERARCH ESO ADA POSANG T 16 2 2148 4096 0 1 32768 0 1 0 ESO LSO 2004 07 08T21 25 30 MPI 2 2 gt FEROS SolarSpectrum 194 999415 29 99999 2000 gt FK5 7 119 9999 53
45. ielded orders of object fibre Format position mm order e Filename f filenum Jext2 bdf Content Extracted and flatfielded orders of sky fibre Format position mm order e Filename rebinned1 bdf Content Wavelength rebinnded orders of object fibre Format wavelength A order e Filename rebinned2 bdf Content Wavelength rebinnded orders of sky fibre Format wavelength order FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 e Filename f filenum 1 bdf Content Merged and wavelength calibrated spectrum of object fibre Format wavelength A e Filename f filenum 2 bdf Content Merged and wavelength calibrated spectrum of sky fibre Format wavelength 45 Appendix C Data Archiving FEROS SCIENCE data are archived in the ESO data archive automatically according to the ESO VLT Data Flow System Specifically for FEROS the NGAST system originally installed for the WFI instrument at the MPG ESO 2 20m telescope is used In anycase since the data are in the ESO archive they can be accessed via the standard tools see http archive eso org FEROS data have been ingested into the ESO Science Archive since the FEROS big bang i e the upgrade to VLT compatibility which was made in November 2003 In addition data since August 31st 2001 has been archived on CD and is maintained by La Silla Science Operations Access to this archive is limited and depends on the availability of La Silla SciOps staff Enquiries s
46. in the following sections In a nutshell the FEROS Calibration Plan provides for the acquisition of daytime calibrations in the afternoon before and the morning after each night s observations At each time a standard set of calibration data acquired A standard calibration data set is currently defined as e 5 BIAS frames e 10 Hal Hal Flatfield frames with a peak intensity of 30 000 ADU exposure times are adjusted peri odically as lamp intensities evolve and old lamps are replaced with new ones e 2 ThArNe Wavelength Calibration frames of 10 sec duration e 2 ThArNe Wavelength Calibration frames of 50 sec duration e 2 ThArNe Wavelength Calibration frames of 100 sec duration The afternoon calibrations are carried out via the execution of Standard Calibration OBs typically loaded into Bob from the OT tool The morning calibrations are carried out automatically using the ESO CALOB tool Afternoon calibrations are normally made only in the default readout mode unless it is certain that some other readout mode will be used during the night The CALOB tool insures that morning calibrations are acquired for each readout mode actually used during the night Additionally to the standard set of calibrations two two minute Solar Spectra normally only in the default readout mode are acquired approximately 1hr before sunset while in the morning on a once every three days basis a Ihr DARK image in each readout mode used during the previous nigh
47. ip index EEV CCD 44 Detector chip name 2048 of pixels along X 4096 of pixels along Y 15 0 Size of pixel in X 15 0 Size of pixel in Y 1 X location in array 0 000000 Gap between chips along x 1 Y location in array 0 000000 Gap between chips along y 1 of chips in detector array 03 10 03 Installation date 0 00000000 Apparent 00 00 00 0 DEC at start ESO VLT DIC CCDDCS ESO VLT DIC FCDDCS Diction 1311 Unique exposure ID number 41 559 image readout time Normal Exposure type 41 682 image transfer time 1 Image sequencial number Normal Type of frame gt Detector system Id feros FEROS Name of detector system 1 Chip to which the output belongs 0 00 Conversion from ADUs to electrons 0 00 Conversion from electrons to ADU R S Output ID as from manufacturer 2 Output index R gt Description of output 2048 valid pixels along X 4096 valid pixels along Y 50 Overscan region in X O Overscan region in Y 50 Prescan region in X O Prescan region in Y 0 00 Readout noise per output e 2048 X location of output 1 Y location of output 1 of outputs O reference output 0 00000000 Apparent 00 00 00 0 RA at start RH 225Kps Low Gai Readout clock pattern used normal Readout method 1 Number of readouts buffered in sin Fast Readout speed Feros shutter Shutter unique identifier 0 001 Time taken to close shu
48. is not guranteed for publication quality 3 2 FEROS instrument modes and basic choices After the detailed description of the FEROS spectrograph its subsystems and functions Chapter 2 we pro vide an overview of the two FEROS observing modes Light from the two fibres simultaneously recorded on the detector permit two observing modes e Object Sky OBJSKY e Object Calibration OBJCAL Apart from the instrument mode a decision has to be made regarding the acquisition of the target Under normal conditions the target is centered directly on one of the fibrehead apertures normally the one defined as the OBJECT fibre due to its superior throughput see figure 2 2 Observing in the two different modes is fully remotely controlled Both modes are offered in both Visitor and Service modes In both modes the internal flatfield FF and wavelength calibration WC light sources are available for the two fibres via remote control of the FCU 3 2 1 The Object Sky Confi guration In the OBJSKY mode two fibres record the star light and nearby sky background simultaneously The Sliding Calibration Selection Mirror in the FEROS WFI Adpater see section 2 3 is in the PARK position The ADC can be used to correct the light from the target for the effect of Atmospheric Dispersion At the 1 52m it was necessary to manually change the fi bre confi guration at the telescope to switch between modes At the 2 20m switching is now achieved via pos
49. itioning of mirrors via remote control 2Not yet implemented FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 21 Table 3 1 Fibre configurations of FEROS mode light sources 1 object OBJSKY OBJCAL object FF WC 2 sky OBJSKY sky FF WC 2 calibration OBJCAL FF WC along with object exposure Both fibres have a projected entrance aperture of 2 0 arcsec This keeps slit losses below 12 for a seeing of 1 5 arcsec and keeps the effect of differential atmospheric refraction up to z 60 airmass 2 negligible For calibration purposes the internal flatfield or the wavelength calibration source are recorded through both fibres 3 2 2 The Object Calibration Confi guration In the OBJCAL mode the object fibre is used as in the OBJSKY mode described above Light from the FCU is delivered to the sky fibre via the appropriate positioning of the Sliding Calibration Selection Mirror in the FEROS WFI Adpater see section 2 3 Then the light of the calibration source either WC or FF can be recorded throughout the whole object exposure to monitor the stability of the spectrograph The position of the neutral density filter wheel is set automatically according to the exposure time With the OC observing mode and the software techniques described below a long term radial velocity accu racy of lt 25m s is reached for sharp lined solar like stars 3 3 Introducing Observation Blocks An Observation Block OB is a logica
50. ive aperture with the new rod lenses is restored to the design specification of 2 0 arcsec as compared to 1 6 arcsec which was the case for the ball lenses The rod lenses thus improve the overall efficiency as well as increasing the throughput as a function of seeing image quality The SCIENCE fibres are of 100 um diameter FV type each measuring approximately 15m in length The current fibres were installed during October 2003 at the same time as the new microlenses replacing the original fibres from the ESO 1 52 m which were also of type FV The main reason for replacing the fibres was to increase the length in order to be able to reduce Focal Ratio Degradation due to stress on the fibres caused by small radius curves necessitated by the less than ideal length of the original fibres The SCIENCE fibres are interfaced to the microlenses using optical glue The intrinsic efficiency ratio between the designated OBJECT and SKY fibres is between 1 6 in the blue and 1 3 in the red varying smoothly between these two extreme values see figure 2 2 The F N Adaption Lens System TBD See the original FEROS Final Design Report downloadable from http www 1s eso org lasilla sciops 2p2 E2p2M FEROS Documentation fdr ps gz FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 11 2 FEROS fiber efficiency test input files fero9004 mt e O o KE Er ue 3 ST Een Ss E os D 8 4 gt o H 4 3 gt Ep E L 4 8 L 4 o 2 L 4 E 0 5
51. kstation IWS if the remote autosave is turned on BIAS command remsave e starts on the IWS the MIDAS programm loadccd fero filenum where filenum is the running 4 digit filenumber of the CCD frame The loadccd program itself e loads the frame fero filenum mt into the display e adds the incoming file to the catalogue Feros cat e writes the FITS file to the DAT drive dev rmt Imn Blocksize 2880 e starts the automatic reduction via autoreduce fero filenum According to the four possible exposure types SCIENCE FLATFIELD CALIBRATION and DARK given in the descriptor EXPTYPE the autoreduce program starts the following actions e FLATFIELD adds the incoming file to the catalogue FF cat 34 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 35 e CALIBRATION adds the incoming file to the catalogue ThAr cat e DARK adds the incoming file to the catalogue Dark cat e SCIENCE adds the incoming file to the catalogue Objects cat start the pre reduction of the the file prered filenum raw Image where raw image is the name of the inputfile for the following on line reduction computes the barycentric velocity according to the telescope position and writes the result to the descriptor BARY CORR computes and subtracts the interorder background of the echelle spectrum BACK FEROS straightens the echelle orders STRAIGHTEN FEROS extracts the echelle orders EXTRACT FEROS removes the blaze function and the
52. l unit specifying the telescope instrument and detector parameters and actions needed to obtain a single observation It is the smallest schedulable entity which means that the execution of an OB is normally not interrupted as soon as the target has been acquired and centered on the fibre An OB is executed only once when identical observation sequences are required e g repeated observations using the same instrument setting but different targets a series of OBs must be constructed The detailed definition of FEROS Observation Blocks and Templates is given in Ref 1 For example one would like to obtain a spectrum of a point source First the instrument mode has to be chosen OBJSKY or OBJCAL The instrument mode is set within the FEROS acquisition observation and calibration templates In addition the information on the target position has to be provided in the acquisition template For the observation itself either the FEROS_ech_obs_objsky or the FEROS_ech_obs_objcal tem plate must be used according to which mode is required The parameters to be set for both modes are the read out mode of the detector see section 2 2 4 and the exposure time and the binning For the OBJCAL mode the additional parameters of which lamp to use and the lamp warmup time must be specified If one likes to carry out a dedicated wavelength calibration after the science exposure the attached wavelength calibration template FEROS_ech_cal_wave has to be
53. lasilla sciops ntt emmi EFOSC at the ESO 3 6 m TBD See http www 1s eso org lasilla sciops 3p6 efosc HARPS at the ESO 3 6 m TBD See http www 1s eso org lasilla sciops 3p6 harps CES at the ESO 3 6 m TBD See http www 1s eso org lasilla sciops 3p6 ces Spectroscopy at infrared wavelengths 1 5 um e Sofl at the NTT TBD See http www 1s eso org lasilla sciops ntt sofi e TIMME at the ESO 3 6 m TBD See http www 1s eso org lasilla sciops 3p6 timmi 1 4 2 Paranal Spectroscopy in the UV Visual Red regions 300 1100 nm e FORS1 at UT2 since June 2004 can be used for spectroscopy in the spectral range 360 1100 nm Its overall efficiency is on average 2 times higher than FEROS one reflection less in the telescope and simpler instrument optics but the maximum resolving power to be obtained with a 0 5 arcsec slit is 2 500 only FORS2 at UT is a replica of FORS1 but it will eventually include two transmission echelle gratings which when used in conjunction with a grism cross disperser will provide a resolving power of up to 6 000 and a wider spectral coverage comparable to that of FEROS GIRAFFE which is part of the FLAMES instrument at the opposite Nasmyth platform of UT2 is the instrument which approaches FEROS in resolution An automatic fibre positioning unit is installed at the Nasmyth focal plane It can use up to 132 fibers in the field of view of 25 arcminutes in diameter The fibers feed t
54. ld be used or WLC expsoures should be attached to each science observation To this purpose the FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 27 user can insert in the OB after the Observation Templates a so called attached calibration template where a lamp is selected and all instrument parameters except the exposure time are left unchanged The telescope will lose the guide star during the lamp operation because the SCSM will obscure the beam from the telescope to the fibrehead However in typical WLC expsoure times errors in tracking will be small and reacquisition of the target onto the fibre to take another science expsoure will be fast The instrument currently repositions the moving functions with great accuracy Taking different WLC spectra after changing the instrument configu ration leads to shifts which are less than 1 207BD of pixel rms This corresponds to errors in radial velocities of less than 50 m sec As a guidance note that 1 hPa millibar change in the pressure corresponds to a shift of about 1 207BD of a pixel A change of 0 3 C induces the same change In a night the air pressure at La Silla can change by several hPa Temperature changes inside the instrument are normally controlled to within 0 5 degrees Celius The file header contains values of the airpressure and temperature at the beginning and end of the exposure 4 4 Flat fi elding There are two internal flat fielding lamps provided by the FCU plus the possibility
55. lescope desclination deg Position angle at end deg ADC mode Telescope right ascension deg If T function is software simulat ADC arm position name Sliding cal sel mirror unique ID Sliding cal sel mirror name Sliding cal sel mirror number Sliding cal sel mirror element Rotating sel mirror unique ID Rotating sel mirror name 2 Rotating sel mirror number Rotating sel mirror element 1 L GC ti Fi rd YD OS OS SS aa A D D A D A A D A A A A A TD A A D D D A A A T T 2000 06 16 Instrument release date yyyy mm d ESO VLT DIC FEROS_ICS 1 5 Data dictionary for 1932 Absolute position Enc 0 000 NDFW Position density FEROS 1 56 Instrument ID T If T function is software simulat 49 50 HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO
56. lux calibrations are in general NOT possible with FEROS due to the diameter of the SCIENCE fibre apertures which project to 2 0 arcsec on the sky meaning that unless the seeing were below 0 1 arcsec losses at the fibre aperture would be impossible to reliably correct for A table of flux standard stars suitable for observations with FEROS is given in the Appendix and standard OBs are available at the telescope 4 7 Quality Control TBD 4 8 Special calibrations 4 8 1 Detector flats Detector flats with direct undispersed illumination of the CCD through the camera are taken at regular intervals according to the FEROS Calibration Plan cf 2 to monitor the CCD performance They are available on request with a valid justification from usg help eso org 3Unfortunately such conditions seldom if ever prevail at La Silla Chapter 5 Observing This Chapter summarizes the instrument related information for the visiting astronomers coming to La Silla to observe with FEROS 5 1 Before the observing nights preparation of OBs Visiting astronomers are normally asked to come to La Silla one night in advance of their observing run They should arrive already well documented on the instrument properties and on the preparation of the OBs for their observing run or ready to finalize them if they have been prepared in advance at the home institute These activities take place on a Linux PC Workstation in the User s Computer Room in
57. m _WLC2 tbl by command INIT FEROS ThAr filenum Format MIDAS Table e Filename ThAr50000 tbl Keyword COEF_WLC Content Table with wavelengths of calibration lines optimized for resolving power R 50000 Used for wavelength calibration Available in MIDAS directory midas 97NOV contrib feros data calib calib000 1 1 Format MIDAS Table e Filename BLAZE tbl Keyword COEF_WLC Content Table with blaze wavelengths of orders Used for order merging Available in MIDAS directory midas 97NOV contrib feros data calib calib0002 mt Format MIDAS Table 44 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 O autoreduce e Filename fero filenum mt Content rawimage in FITS format as transferred to the instrument workstation Format pixel pixel e Filename raw_image bdf Content MIDAS frame after prereduction of the rawimage Format position mm position mm e Filename back bdf Content Background subtraced frame Format position mm position mm e Filename back_str_C1 bdf Content Straightened frame of object fibre Format position mm pixel e Filename back_str_C2 bdf Content Straightened frame of sky fibre Format position mm pixel e Filename b filenum extl bdf Content Extracted orders of object fibre Format position mm order e Filename b filenum ext2 bdf Content Extracted orders of sky fibre Format position mm order e Filename f filenum ext1 bdf Content Extracted and flatf
58. mination of scheduling constraints e g visibility time critical observations e Overview observation plan e g target list calibration needs Phase II for successful applicants e Identification of detailed instrument set ups e Identification of target acquisition requirements e g finding charts offset star e Preparation of needed Observation and Calibration Blocks Part of the observing time at the MPG ESO 2 20 m telescope is carried out in service mode by the Observa tory Staff e in absence of the applicant All information necessary to successfully execute the proposed observing program has to be provided in the form of Observation Blocks finding charts and other relevant information in advance of the observations to ESO following the instructions sent to the applicants The Observatory staff will combine the execution of different programs in the same night optimizing the time 19 20 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 sequence and the seeing and moon requirements Observations carried out with the applicant present at the telescope are referred to as visitor mode observations In this mode the astronomer prepares or finalizes the OBs at the Observatory in advance of his her nights He she decides about the sequence of observations during the night but their execution is however still performed by the telescope and instrument operator TIO To facilitate the preparation of Phase I and Phase II prop
59. mplates allow to enter additional velocities in right ascension and declination in units of arseconds per FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 23 second The target is identified on the image of the FEROS Fibrehead Viewer FFHV by the visiting astronomer or in case of service observations by the ESO staff astronomer The target is identified by clicking on it with the mouse and automatically positioned on the fibre The tracking of the telescope is corrected for errors of low frequency lt 1 Hz by an autoguiding facility Normally guiding is performed on the target itself on the fibre guiding on fibre using the FFHV But in crowded fields one or more field stars of comaprable brightness i e within 3 mag within 10 arcsec of the target a field star in the field of view of the FFHV can be used guiding on fieldstar In this case it is not possible to check the centering of the object on the fibre during the observation except by momentarily turning off the autoguiding however the guiding is reliable for at least 1 hr so this is not normally necessary In extreme cases when there happens to be one contaminating field star near the target thus preventing guiding on fibre but no other field stars suitable for guiding within the field of view of the FFHV the WFI tracker chip can be used for guiding With a field of view of 10 x 21 arcmin a suitable guide star is ALWAYS available For guiding on fibre a Dynamic Centerin
60. n cies and an efficiency of 60 for the 2 20m telescope a spectrum of a 10th magnitude star can be taken in 10 minutes with a S N 100 in V Within one hour for a star of 16th magnitude a S N of 10 is reachable in good observing conditions Furthermore making appropriate assumptions on the reflectivity of the three telescope mirrors also tabu lated at the above webpage the overall telescope instrument detector efficiency has been computed and compared with measurements of the standard stars observed during the commissioning corrected for atmo spheric absorption Observations agree well with theoretical expectations with a maximum peak efficiency of approximately 19 being measured see figure 2 4 during the November 2003 commissioning see 4 Observations of spectrophotometric standard stars are acquired on most nights as part of the FEROS Calibra tion Plan see http www 1s eso org lasilla sciops 2p2 E2p2M FEROS CalPlan and are archived at http www 1s eso org lasilla sciops 2p2 E2p2M FEROS InstrumentCharacteristics InstrumentEfficiency html Not yet implemented Typically due to imperfect atmospheric transparency less than ideal seeing i e worse than 1 0 arcsec and imperfect focusing of the telescope peak efficiencies of 10 17 are achieved from night to night though 20 peak efficienies is certainly not unknown 2 5 Instrument Features and Problems to be aware of TBD 2 5 1 CCD Cosmetic Defects The F
61. nd so requires 10 15mins including to for TIO to get to from the telescope from the RITZ The ThArNe lamp is the default Wavelength Calibration source since June 2003 Prior to that the ThAr Ne was the default and only Wavelength Calibration source Selection between the sources is made simply by the Rotating Selection Mirror RSM see figure 2 3 The RSM is used to select the source projected onto the collimator The FCU Shutter then selects which fibre s the beam is able to illuminate After the shutter two lenses focus part of the beam onto each CAL IBRATION fibre input Between the lenses and the fibre inputs is a Neutral Density Filter Wheel NDFW which allows to control the flux level in OBJCAL mode so that it is possible to match the flux level in the calibration spectrum in long SCIENCE exposures to the flux obtained in the much shorter calibration expo sures The dynamic range of the NDFW is approximately 0 0 2 5 thereby allowing flux matching OBJCAL exposures of exposure time from 1 0 316 times the exposure time of the calibrations Since useful ThAr can be obtained with exposure times from 10 100 sec this means OBJCAL exposures from 10 31 600 sec are possible though of course other constrainst limit maximum reasonable exposure times to of the order of 1 hr 2 3 FEROS WFI Adapter TBD 4Manufacturer make an model TBD FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 15 2 4 Spectral Coverage Resolution
62. nding FEROS MIDAS descriptors When converting FITS files to MIDAS bdf some of the standard FITS keywords are converted into standard MIDAS descriptors The following table lists the most important conversions FITS MIDAS OBJECT IDENT RA 0_POS 1 DE O0_POS 2 DATE OBSO_TIME 1 TM STARTO_TIME 5 EXPTIME O_TIME 7 Appendix E Acknowledgements This User Manual is based on the UVES User Manual issue 1 9 dated June 2004 kindly provided by C Ledoux and S Hubrig of Paranal instrument support the current maintainers of the UVES manual The original authors of the UVES User Manual are A Kaufer S D Odorico and L Kaper and their contribution to this manual via their original authorship of the UVES manual is hereby acknowledged This user manual also draws extensively from the original FEROS User Manual written by Patrick Francois and his extensive contribution to this manually is likewise gratefully acknowledged op 53
63. nt wind directio Observatory ambient wind speed que True when chopping is active 22000 10 15T15 21 35 745 TCS installation date TCS 1 8 Data dictionary for TEL Dome status Telescope focus station ID Focal length m Focal scale arcsec mm M2 setting mm Elevation above sea level m Tel geo latitute North deg Tel geo longitute East deg TCS version number 03 04 12 7 DEC J2000 deg 00 47 01 7 RA J2000 deg Telescope Operator Tracking rate in RA arcsec sec Tracking rate in DEC arcsec sec 51 52 HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH ORIGFILE FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 ESO TEL TRAK STATUS NORMAL Tracking status ESO TPL DID ESO VLT DIC TPL Data dictionary for TPL ESO TPL EXPNO 1 Exposure number within template ESO TPL ID FEROS_ech_obs_objsky Template signature ID ESO TPL NAME FEROS obs object sky Template name ESO TPL NEXP 2 Number of exposures within templat ESO TPL PRESEQ FEROS_ech_obs_objsky seq Sequencer script ESO TPL START 2004 07 08T21 23 01 TPL start time ESO TPL VERSION 71 0 Version of the template FEROS_ech_obs_objsky_0001 fits Original File Name ARCFILE FEROS 2004 07 08T21 23 29 396 fits Archive File Name CHECKSUM 9aoDJUOA9ZOAGZOA ASCII 1 s complement checksum The correspo
64. on facility only and not suitable for publication 3As against maintenance templates Implemented within a standard MIDAS context Context feros of course Chapter 6 The reduction of FEROS data 6 1 Real Time Display and quick look As as they are read out by the FIERA Controller and transferred to the instrument WS the CCD frames are automatically displayed on a Real Time Display RTD panel on a screen of the instrument WS The visiting astronomer can use the standard tools of the RTD on the astronomer s offline WS to visually display and inspect the spectra to produce intensity traces and to compute the statistics of pixels values in a subwindow Previous exposures can be reloaded 6 2 Pipeline reduction of FEROS data ESO has developed a pipeline reduction for FEROS which primarily supports 1x1 binning modes as available in Service Mode For visitors observing with non standard settings i e 2x2 binning the on line pipeline at La Silla can in general not be prepared to handle this setting The science data are calibrated with calibration exposures obtained in the afternoon before the start of the night The FEROS Calibration Plan cf 2 ensures that ESO maintains and provides bias images spectroscopic flatfield spectra calibration lamp spectra solar spectra and spectrophotmentric standard star spectra The CCD characteristics like read out noise and gain are currently measured on a daily basis Dark current and pa
65. or the blaze function of the different orders be fore merging Such calibrations are obtained each night during Serice Mode as part of the FEROS Calibration Plan During Visitor Mode nights such observations are strongly encouraged Normally telescope focusing using a spectrophotometric standard star field followed by two two minute science exposures of the spec trophotometric standard can be made approximately 30mins after sunset and will thus normally finish well before the official start of the night thus minimally impacting even on Visitor Mode programmes In addi tion the instantaneous atmosphere telescope instrument efficiency is measured and reported by the FEROS The specifi cation for temperature stability within the FEROS Climate Controlled Room and hense the instrument itself is 0 5 degrees Celcius In practice during a given night temperature stability id generally better than 0 2 degrees Celcius though from day to day the variations can be somewhat larger A continuously updated database of recorded environmental sensor data can be found at http ww ls eso org lasilla sciops 2p2 E2p2M FEROS EnvMonArchive Equivalent to the slit function of conventional spectrographs 28 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 pipeline within minutes of the expsoures thus giving the observer practically instantaneous feedback on the qwuality of the night which can be useful for planning the rest of the nights observing Absolute f
66. ormed with clipping of cosmics 2 MERGE_MTD controls the merging of the orders The options are SET FEROS MERGE_MTD SINC the default merging into a 1D spectrum with weighted adding of overlapping regions The lengths of the orders are determined from table BLAZE tbl SET FEROS MERGE_MTD AVE should not be used SET FEROS MERGE_MTD NOAPP the orders are not merge but written into individual 1D spectra the order number is appended to the filename as 4 digit number 3 REBIN_MTD controls the rebinning of the spectra The options are SET FEROS REBIN_SCL I the rebinning is done into a linear wavelength scale The stepsize has to be set in the keyword REBIN_STEP SET FEROS REBIN_SCL 0 the rebinning is done into a logartithmic wavelength scale The stepsize has to be set in the keyword REBIN_STEP A 4 Utility programs A 4 1 List of fi les An extended list of files with the most important header informations can be obtained with the command listferos tablename filenum_start filenum_end where tablename is the name for the output table filenum_start filenum_end are the 4 digit filenumbers of the interval of files to be listed The program will ask at the end to prepare a printout on the laser printer It will take care of the proper formatting of the printer output It is recommended to use this program at the end of the night to check the integrity and completeness of the data files obtained during the night before archiving them on t
67. osals besides the information provided in this User Manual an ETC is provided courtesy of the Landessternwarte Heidelberg Konigstuhl the major partner of the consortiuum who built FEROS under contract to ESO The ETC permits to estimate the signal to noise ratio for a given configuration and exposure time taking into account specific atmospheric conditions at approximately the wavelengths of standard UBVRI photometric filters The Observing Blocks are prepared using another ESO provided software tool called P2PP see 8 and http www eso org observing p2pp Before preparing the observations it is advisable to review the FEROS webpages http www 1s eso org lasilla sciops 2p2 E2p2M FEROS which give information on current problems and possible new instrument artifacts detected during the current observing period and not yet described in the FEROS User Manual A FEROS data reduction pipeline is also running at the Observatory It enables automatic extraction and wavelength calibration of all spectra of stellar objects taken with FEROS It permits an on line check of the quality of the observations resolution S N in the extracted spectra The science data are calibrated with calibration exposures obtained on a daily basis as part of the FEROS Calibration Plan Note that the FEROS on line pipeline is intended as a quick look and quality control tool and was designed for robustness of the reduction and not for best possible reductions It
68. perature 0 009428 14 79 gt TEMP4 S 14 430000 14 430000 14 430000 Temperature 0 000000 14 43 TEMPS 14 570000 14 563333 14 560000 LSO MAN ESO 22200 0001 FEROS WFI sel mirror name Instrument mode used Optical path used sensor ID Maximum value Average value Minimum value sensor common name RMS of samples over exposure Sensor numeric value sensor ID sensor common name Sensor numeric value FCU shutter unique ID FCU shutter name FCU shutter number If T function is software simulat FCU shutter element Software simulation Temperature sensor ID Maximum value C Average value C Minimum value C gt Temperature sensor name RMS of samples over exposure Temperature sensor numeric value Temperature sensor ID Maximum value C Average value C Minimum value C gt Temperature sensor name RMS of samples over exposure Temperature sensor numeric value Temperature sensor ID Maximum value C Average value C Minimum value C gt Temperature sensor name RMS of samples over exposure Temperature sensor numeric value Temperature sensor ID Maximum value C Average value C Minimum value C gt Temperature sensor name RMS of samples over exposure Temperature sensor numeric value Temperature sensor ID Maximum value C Average value C Minimum value C FEROS II User Manual 1 4 HIERARCH HIERARCH HIERARCH H
69. r the final step of target acquisition The FFHV images are properly oriented in the sky and the coordinates which can be read with the cursor are converted to sky coordinates The target coordinates entered in the OBs have to be accurate to better than lt 1 to avoid unnecessary waste of telescope time in the identification process The image of the FFHV field Remote Integrated Control Zentrum 2The MPG ESO 2 20 m telescope the ESO NTT telescope and the ESO 3 60 m telescope 29 30 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 is automatically archived at the end of the acquisition The telescope pointing rms accuracy is of the order of 5 arcsec so that the target does appear close to the center of the FFHV images displayed on the WS panel or if the telescope Coordinate Correction has been previously made with a target on the fibre then very close to if not well centered on the fibre The visiting astronomer has to validate the target identification on the image This is particularly important if the field has other close by objects of similar magnitude Note that if the target is invisible to the limit of the FFHV camera e g an emission line nebula it is possible to define in the OB a blind offset from a nearby visible star The coordinates of the science target have to be entered in the target description In the acquisition template of the OB the offsets to the guidestar have to be entered in arcseconds target coordinates off
70. rasitic lightT BD measurements are carried out once every three days and are available on request from the ESO archive for SM programmes 1f not by chance included in the data package and in the data package for Visitor Mode programmes Both optimum and standard extraction modes are possible however there are currently problems of an un known origin with the optimum extraction method resulting in a semi sinusoidal modulation of some spectra which appears and disappears from exposure to exposure More information about the FEROS pipeline and Service Mode data packages is available under http www 1s eso org lasilla sciops 2p2 E2p2M FEROS DRS 6 3 Off line data reduction Any echelle data reduction package under MIDAS IRAF or based on IDL can be easily adapted to extract and calibrate FEROS data MIDAS has a dedicated context feros which uses the instrument s physical model to speed up the order definition and wavelength calibration This is the same pipeline run at the telescope though the latest version of the user procedures should be obtained from the La Silla FEROS DRS web page http www 1s eso org lasilla sciops 2p2 E2p2M FEROS DRS 31 32 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 Various parameters and techniques can be applied to improve the quality of the reduction over that typically achieved at the telescope Most recently on the 1 of November 2003 the content of the FEROS FITS image header
71. records were complete revised and due to the change over from the Copenhagen University BIAS CCD controller system to the ESO standard FIERA CCD controller system The standard version of the FEROS DRS user procedures as provided by any standard MIDAS installation do not know how to cope with these changes The version of these procedures provided at the La Silla FEROS DRS web pages see above is specifically intended to be able to cope with data from all epochs of FEROS s history from the original BIAS system installed at the ESO 1 52 m telescope to the slightly modified BIAS system as originally instralled at the MPG ESO 2 20m telescope to the current FIERA based system ln order to achieve VLT standard DICB compliance Chapter 7 Other useful information 7 1 List of standard stars Any flux standard star can be used for flux calibration and blaze correction The standards to be preferred should have measurements at a step of 2 nm or less to have at least a few points for each echelle order For the pipeline reduction it is necessary to use stars for which the flux Table is available in MIDAS In particular flux standards from the MIDAS calib data spec ctio directory will be automatically recognised the efficiency will be calcualted and reported The FEROS webpage http www 1s eso org lasilla sciops 2p2 E2p2M FEROS CalPlan contains a pointer to the lists of flux standards 7 2 Lists of arc lines Tables of the ThAr and Ne lines
72. rref hbin action where table is a name for the table with the results the results from subsequent calls of the program will be appended to the table object objectref thar tharref refer to the 4 digit numbers of the files described above With hbin the size of the histogram bins to be used for the final determination of the radial velocity defaulted to 0 150 km s If the program is called the very first time action should be set to create to add the results from new reductions action has to be set to enter e The results can be plotted over the modified julian date MJD with the command plot table table jd24 dbc 5 Example for the first reference night Midas 11 gt UNBLAZ FERO ThAri200ext FF1202ext 1200ext Midas 12 gt xcorall 51Peg 1212 1212 1200 1200 create Midas 13 gt xcorall 51Peg 1212 1212 1200 1200 enter For an observation from a later night 40 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 Midas 698 gt UNBLAZ FERO ThAr1410ext FF1212ext f1410ext Midas 699 gt 00 xcorall 51Peg 1417 1212 1410 1200 enter Midas 700 gt plo tab 51Peg jd24 dbc If a large number of Object Calibration exposures has been obtained for one object the command radvel objectcat objectref tharcat refthar hbin gives the possiblity to reduce all files at once For this a MIDAS catolgue objectcat with all f object ext1 bdf files and a MIDAS catolgue tharcat with the corresponding f thar ext1 bdf
73. rs for the high gain slow and medium gain Very Fast readout modes MAXIMUM EXPOSURE INTENSITY TIME REMARKS ADU sec ThArNe 10 50 100 D spectral lines above 350nm Hal Hal 120 use D lamp below 340nm ThAr Ne 30 150 300 D Hal TBD D has spectral lines above 350nm but is still better than nothing FCU is delivered to the fibrehead via the CALIBRATION fibres Table 4 2 lists the lamps and exposure times to be used for three readout mode unbinned 4 3 Calibration in wavelength The ThArNe lamp provides accurate wavelength calibrations over the complete spectral range when the FEROS matched line table available from in the MIDAS calib data and from the FEROS DRS web page tt http www Is eso org lasilla sciops 2p2 E2p2M FEROS DRS is used The rms of the wavelength fit is typically better than 0 009 Wavelength calibration WLC exposures using either ThArNe or ThAr Ne lamps can be made simultane ously with the science exposures in the OBJCAL mode to minimize the effects of changing temperature and or pressure or of a small earthquake Alternatively WLC exposures can be taken immediately after the science exposures Typically however even for high precision radial velocity work it is only necessary to take a few WLC expsoures dispersed thorugh the night Yhis is valid for Visitor Mode programmes but is NOT done for Service Mode programmes For SM programmes requiring high precision radial velocitis either the OBJCAL mode shou
74. rst Colimator then the Echelle Grating back to the first Collimator then the Flat Folding Mirror then the Second Collimator the Cross Dispersing Prism through the Camera before finally arriving at the CCD The spectrograph functions and components The fibre head consists of a polished block of Aluminium The polished surface is curved in order to provide uniform focus across the field of view of the fibrehead in the fibrehead viewer The fibres are mounted into the fibrehead via brass inserts which hold the microlenes and fibres in place The microlenes are rod type lenses consisting of type glass with a MgF Anti Reflection coating The microlenes re focus the f 8 input beam to f 4 6 as required by the spectrograph design The current microlenes were installed during October 2003 They replaced the former spherical lenses which were installed when FEROS was first moved from the ESO 1 52 m to the 2 20 m during October 2002 The microlenses used in the ESO 1 52 m fibrehead were rod lenes and indeed rod lenses were the preferred design for the 2 20 m fibrehead but at the time of moving FEROS to the 2 20m a manufacturer capable of fabricating lenses to the required specifications could not be found A Company capable of fabricating the required rod lenses was subsequently discovered As compared to the ball lenses the rod lenses provide a much improved optical matching between telescope and fibres An important improvement being that the effect
75. rum thar from the ini tialization of the night order by order with the corresponding calibration spectrum from the reference night tharref to obtain the zero point of the night For the object spectrum obtained during the night object the program crosscorrelates the simultaneous calibration spectrum on the calibration fibre with the calibration spectrum on the calibration fibre from the initialization to obtain the drift correction between the zero point of the night and the actual object exposure The object spectrum object is crosscorrelated with the object spectrum from the reference night objectref The measured radial velocity shift is corrected for the zero point the drift during the night and the barycentric correction The final radial velocity is obtained by gaussian fitting of the histogram of the derived radial velocities of all orders To use the corresponding xcorall program the following steps are necessary e initialize the DRS as described above in the Object Sky mode The calibration exposure has to be flatfielded with the command UNBLAZ FERO ThAr thar ext FF flat ext f thar Jext where thar flat correspond to the 4 digit numbers of the intialization frames of the night e observe the object in Object Calibration mode and let the on line DRS reduce the spectrum as usual Make sure that the EXT_MODESS is used e Use afterwards the crosscorrelation program xcorall table object objectref thar tha
76. scope is moving to a new object at 180 degrees from the current pointing al lowing for accurate acquisition onto the fibre and time for the autoguiding to get the object accurately centered on the fibre and finally GRABing the FFHV image the whole sequence can be completed in 6 minutes If the new target requires just a small motion of the telescope and the re acquisition of the guiding star 4 min e Adapter and calibration unit set up and CCD read out time Changing from OBJSKY to OBJCAL mode or vice versa or changing from SCIENCE to CALIBRA TION exposures take at most 1 minute Changing from one CALIBRATION type to another e g from FF to wavelength calibration takes 10sec When turning on the calibration lamps it a warmup time must considered During daytime calibrations both FF and wavelength calibration lamps are warmed up for 5 mins before being used During nighttime a 1 min warmup for the FF lamp is probably a suit able compromise between lamp stability and the desire not to waste too much time during the night while a warmup for the wavelength calibration lamp can probably be safely skipped The read out time for the CCD 1 port is 24 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 slow read out mode 60 kHz unbinned 148 seconds fast read out mode 225 kHz unbinned 41 seconds The shortest possible cycle time with the FEROS instrument can be achieved by the use of the gt ultrafast read out mode 625 kHz
77. sets acquisition star coordinates Whatever the acquisition procedure once the instrument operator signals that the target is centered on the fibre the exposure is started The tracking of the telescope is corrected for errors by the autoguiding usually using guiding on fibre in the FFHV 5 2 2 Monitoring the integration There is unfortunately no facility to monitor the development of the observation no flux meter or anything 5 2 3 Evaluation of the results off line data analysis At the end of each integration the CCD frame is read out by the FIERA controller and transferred to the Instrument Workstation and subsequently to the archive At the same time the frames are displayed automati cally on two Real Time Display RTD panels They can be analysed using the standard RTD tools Previous exposures can be re loaded when necessary Data obtained with observing templates are also reduced on line by the FEROS instrument pipeline using a pre populated calibration database The raw files and the products of the pipeline are FITS files cf Chapter 6 2 They can be accessed and inspected by the astronomer on the assigned off line WS which is also avail able for running the major image analysis systems like MIDAS IDL and IRAF This preliminary reduction extraction wavelength calibration flat fielding and sky subtraction provides advanced information on the quality of the obtained data but has to be regarded as a quick look reducti
78. spectrum measures the FWHM of the emission lines and plots the FWHMs over the position in dispserion direction A FWHM of 2 2 pixels corresponds to a resolving power of R 48 000 A 4 5 System effi ciency test After a spectrum fero filenum mt of a standard star has been taken and the spectrum has be passed the auto matic standard reduction the command efficiency filenum standard star flux table computes the efficiency of the instrument including the telescope fibres and the detector as function of the wavelength The flux tables of the standard star must be available in the subdirectories of midas calib data spec and have to be given with the subdirectory e g as ctio hr9087 A 4 6 Radial Velocities by Cross Correlation Radial velocities with high precision can be obtained in the OC mode of FEROS The on line DRS provides a very simple cross correlation tool to obtain online radial velocities with respect to one reference exposure of the object FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 39 It should be emphasized that the routines described here are meant as on line tools to obtain an estimate for the measured radial velocity shifts However to obtain high precision radial velocities over long periods dedicated reduction software and special operational precautions have to be taken This is beyond the scope of the FEROS on line DRS The algorithm works as follows The program crosscorrelates the calibration spect
79. t and a set of CCDTest test data using the Red LEDs 4 2 The FEROS calibration unit As described in section 2 2 5 the FEROS Calibration Unit FCU provides internal flatfield and wavelength calibration sources The FCU is installed in the FEROS Room not mounted on the telescope Light from the 25 26 FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 Table 4 1 FEROS Science Data Calibration Plan Note that same calibrations are applicable for both OBJSKY and OBJCAL mode Calibration number frequency 1 days purpose Internal Flatfields creation of master flats attached Flatfields high precision flatfielding Dome Flatfields Fringe correction in red orders Internal Wavelength dispersion solution resolving power attached Wavelength high precision wavelength calibration Bias creation of master biases Dark creation of master darks Flux Standard response correction flux calibration Telluric Standard removal of telluric spectrum Radial Velocity Std absolute radial velocity calibration o r on request only corresponding OBs to be provided by user n n 6 n 5 1 2 n n number to be defi ned by user Table 4 2 Exposure times for Calibration Lamps unbinned high gain fawst readout mode CCD pixel saturation occurs at 65000 ADU but the response is linear only to 150 000 e or 40000 ADU Exposure times have to be scaled down by a factor of 1 4 for the 2x2 binning and by the ratio of the Conversion facto
80. ters A summary of the properties of the scientific CCD is given in Tab 2 1 The detector consists of one EEV CCD EEV 44 82 Windowing of the CCD is not allowed Two read out modes of the CCD can be selected 1 Low gain fast read out VM SM 2 High gain slow read out VM SM Both 1x1 and 2x2 binning are possible in both read out modes The second digit in binning applies to the direction of the spectral dispersion The characteristics of these modes are given in Tab 2 1 The linearity of the CCDs is measured to be better than 1 over the range from 200 e to the saturation limit Note that counts per pixel above 40000 ADU should be avoided in the low gain readout mode because of non linearity The CCD parameters are periodically remeasured as part of the FEROS calibration plan 2 The updated values are entered in the instrument database and are recorded in the FITS headers for use in the data reduction The cosmetic quality of the scientific CCD is good Details are given in section 2 5 1 The CCD cryostat is not attached to the dioptric camera but is mounted independently of the camera directly onto the optical bench A rubber seal between the shutter and the CCD provides light protection The CCD is operated at a temperature of 139 K 120L liquid nitrogen tanks ensure continuous operation without manual intervention for 2 weeks The shutter is located between the cryostat window and the camera It is actuated by a metali
81. the telescope adapter is possible in the rare case that a field star by chance falls on the sky fibre The resolving power is 48 000 achieved with a two slice image slicer over the spectral range of 350 920 nm spread over 39 e chelle orders The detector is an EEV 2kx4k CCD The instrument is built for maximum mechanical stability and for accurate calibration of the wavelength scale down to an accuracy of at least 50 m s Wavelength calibration spectra can be obtained simultaneous with the science exposure for observations requiring higher accuracy FEROS was first installed at the ESO 1 52m telescope in late 1998 In October of 2002 FEROS was transferred from the ESO 1 52 m telescope to the MPG ESO 2 2 m telescope In October November of 2003 it was upgraded to full VLT compliance i e OB controlled observing The main capabilities of FEROS are summarized in Table 1 1 Echelle Grating Transfer Collimator Figure 1 1 FEROS optical system from fibre exits to detector 1 4 FEROS within ESO A detailed overview of the different ESO instruments is given on the ESO homepage under Instrumentation http www eso org instruments In the choice of the best instrument for a given observing program the following trade offs have to be taken into consideration FEROS II User Manual 1 4 LSO MAN ESO 22200 0001 1 4 1 La Silla Spectroscopy in the UV Visual Red regions 300 1100 nm EMMI at the NTT TBD See http www 1s eso org
82. tter 0 001 Time taken to open shutter IRIS type of shutter FEROS II User Manual 1 4 HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH HIERARCH ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO ESO DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DET DPR DPR DPR INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS INS SOFW MODE TELE INT TELE NO TLM1 END TLMi ID TLM1 NAME TLM1 START TLM2 END TLM2 ID TLM2 NAME TLM2 START WIN1 BINX WIN1 BINY WIN1 DIT1 WIN1 DKTM WIN1 NDIT WIN1 NX WIN1 NY WIN1 ST WIN1 STRX WIN1 STRY WIN1 UIT1 WINDOWS CATG TECH TYPE ADC1 DEC ADC1 END ADC1 MODE ADC1 RA ADC1 SWSIM ADC2 DEC ADC2 END ADC2 MODE ADC2 RA ADC2 SWSIM ADCA NAME
83. ttp www 1s eso org lasilla sciops 2p2 E2p2M FEROS Documentation fdr ps gz 2 2 3 The Fibrehead Viewer CCD FEROS includes two CCD systems the FEROS FibreHead Viewer FFHV technical CCD and the scientific CCD detector The fibrehead viewer unit incorporate Peltier cooled 288 x 385 224m pixel frame transfer front illuminated CCDs on which an image of the fibrehead plane is focussed with a scale of approximately 0 5 arcsec pixel The unvignetted field is approximately 4 x 6 arcmin square NS EW A Johnson V filter is permanently mounted between the fibrehead and the TCCD The objective is focussed on the surface of the fibrehead It is used to identify the target to center it on the fibre aperture and for guiding both on the object on the fibre default or on a field star when not possible to guide on the object on the fibre e g due to a close i e within 5 arcsec field star The limiting magnitudes of the FFHV cameras for target acquisition are a function of seeing color of the target and sky brightness As an example with a 5 sec integration 1 arcsec FWHM seeing and dark sky an object with m V 17 is detected with adequate S N for acquisition and guiding The FFHV camera is generally able to acquire all objects for which spectroscopic observations can be made If the target is too faint to be visible on the FFHV blind offset procedures from a nearby star are provided cf Ref 1 2 2 4 The Scientific CCDs and the associated shut
84. used in the pipeline reduction are available in the FITS table ThAr50000 mt contained in all guess session archives a selection of which are available from La Silla FEROS DRS web page http www 1s eso org lasilla sciops 2p2 E2p2M FEROS DRS 7 3 Pointers to FEROS sample observations TBD Provided the name of the standard is entered in the target name field of the acquisition template exactly as it is correspnding filename in the MIDAS calib data spec ctio directory 33 Appendix A Using the DRS pipeline at the telescope Note the following is now somewhat out of date at least in some of the details though most of the general information is still correct The FEROS on line data reduction software DRS gives the possibilty for a complete standard reduction of the science spectra which arrive during the night from the CCD system The on line DRS is based on the MIDAS context feros which will be distributed from MIDAS version 98NOV on A short intoduction to the MIDAS context feros is found here To install the on line DRS after the DRS is installed all MIDAS programs of the directory midas lt MIDASVERSION gt contrib feros locproc have to be copied to the local midwork directory After CCD readout the BIAS program e includes the status informations from the CCD the Telescope Control System TCS and the Instrument Control System ICS in the FITS header e transfers the 2D spectra are to the instrument wor
85. wer FEROS WFI Adapter Image Slicer La Silla Observatory Observation Block Observation Software Observation Template for a scientific target Phase II Proposal Preparation Real Time Display Sliding Calibration Selection Mirror Standard star Service Mode Template Signature File Very Large Telescope Visitor Mode Chapter 2 Instrument Characteristics 2 1 Opto mechanical layout Figure 1 1 gives the optical layout of FEROS The complete instrument consists of three main parts e The FEROS WFI Adapter e The Spectrograph e The FEROS Calibration Unit The FEROS WFI Adapter FWA is mounted at the cassegrain focus of the MPG ESO 2 20 m telescope It includes an mirror M3 mounted on an arm which moves in and out of the beam to select between FEROS mirror IN beam and WFI mirror OUT of beam With M3 in the telescope beam is reflected onto the downward facing fibrehead which is a polished solid aluminium block The SCIENCE fibres are mounted into the back of the fibrehead and are illuminated via the fibrehead apertures holes 2 0 arcsec in diameter on the sky separated by 2 9 arcmins oriented EW of each other in the default orientation of the telescope rotator The FWA also includes the Sliding Calibration Selector Mirror SCSM which is used to control which of the SCIENCE fibres is illuminated by light from the CALIBRATION fibres whose exit is also mounted in the Adapter An Atmospheric Dispersion Corrector is cuurently bein

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