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CRIRES User Manual

1. 27 1 i 2117 119 tbd 2093 081 2103 354 2106 193 2116 038 2118 626 2128 031 2130 467 2139 418 26 1 n 2149 345 tbd 2115 465 2127 131 2130 362 2141 597 2144 558 2155 349 2158 153 2168 484 26 1 i 2149 345 tbd 2122 287 2133 842 2137 041 2148 165 2151 095 2161 772 2164 546 2174 761 26 1 n 2198 514 tbd 2167 307 2178 088 2181 068 2191 407 2194 125 2204 008 2206 569 2215 981 26 1 i 2198 514 tbd 2173 553 2184 220 2187 168 2197 392 2200 079 2209 845 2212 375 2221 670 25 1 n 2235 357 tbd 2200 128 2212 258 2215 617 2227 301 2230 379 2241 600 2244 515 2255 257 25 1 i 2235 357 tbd 2207 221 2219 236 2222 563 2234 129 2237 176 2248 279 2251 162 2261 785 25 1 n 2286 416 tbd 2253 963 2265 175 2268 274 2279 026 2281 852 2292 130 2294 794 2304 582 25 1 i 2286 416 tbd 2260 458 2271 552 2274 617 2285 250 2288 044 2298 201 2300 832 2310 498 24 1 n 2328 540 tbd 2291 851 2304 484 2307 983 2320 150 2323 356 2335 043 2338 079 2349 266 24 1 i 2328 540 tbd 2299 238 2311 751 2315 216 2327 262 2330 435 2341 998 2345 002 2356 065 24 1 n 2381 640 tbd 2347 835 2359 514 2362 742 2373 941 2376 886 2387 591 2390 366 2400 562 24 1 i 2381 640 tbd 2354 601 2366 157 2369 349 2380 425 2383 335 2393 915 2
2. Figure 5 Top view of the warm optics of the MACAO CRIRES system From f 15 Nasmyth focus and after the optical derotator one notice the deformable mirror and tip tilt mount assembly Light enters from the dichroic to the cold and warm part of the instrument For the latter the wavefront sensor and some analysis tools are visible 11 Figure 6 Assembly of the deformable mirror and tip tilt mount left and of the gimbal mount right 3 2 1 The corrective optics The wavefront correction is performed by a 60 electrodes bi morph mirror developed by CILAS with a pupil diameter of 60mm The 60 electrodes sandwiched between two thin piezoelectric PZT layers with opposite polarization The outside surface of the PZT layers are grounded and covered with 0 1mm glass layers the mirror side being silver coated Applying a voltage to one electrode produces a constant curvature over its surface The geometry of the electrodes in the 4 central rings 40 electrodes matches that of the lenslet array sub apertures while the 20 re maining electrodes are located outside the pupil and constrain the edge of the pupil to correct O curvature aberrations tip tilt astigmatism etc The deformable mirror DM provides a stroke to compensate atmospheric aberrations up to a optical seeing of 1 In order to relax the use of the outer electrodes of the mirror the tip tilt error is slowly offloaded to a tip tilt mount designed and built by LESIA which p
3. Organisation Europ ene pour des Recherches Astronomiques dans l H misph re Austral Europaische Organisation f r astronomische Forschung in der s dlichen Hemisphare ES EUROPEAN SOUTHERN OBSERVATORY o A ESO European Southern Observatory Karl Schwarzschild Str 2 D 85748 Garching bei M nchen Instrumentation Division CRIRES User Manual Doc No VLT MAN ESO 14500 3486 Issue 1 Date 06 01 2006 Prepared for Review INTERNAL USE ONLY Ralf Siebenmorgen 06 01 2006 Prepared so cx anche ete a ee S T yen wis ho Rede hed CRIRES User Manual VLT MAN ESO 14500 3486 Change Record Issue Rev Date Section Parag affected Reason Initiation Documents Remarks Issue 0 5 06 12 04 RSI First draft CRIRES User Manual VLT MAN ESO 14500 3486 Abbreviations and Acronyms AO APD CRIRES DM DMD ESO ETC FC FoV FWHM NIR OB P2PP PSF QC RTC SM SR TIO USG VLT VM WF WFS Adaptive optics Avalanche photo diode High resolution infrared echelle spectrometer of the VLT Deformable mirror Data management division European Southern Observatory Exposure time calculator Finding chart Field of view Full width at half maximum Near infrared Observing block Phase ll proposal preparation Point spread function Quality control Real time computer Service mode Strehl ratio Telescope and instrument operator User support group Very large telescope V
4. 7 3 The influence of the Moon 7 4 Target Acquisition 7 5 Offset conventions and definitions 7 6 Overheads Il CRIRES data format 8 The CRIRES data reduction cookbook IV Reference Material 9 CRIRES scientific calibration 10 CRIRES template reference 10 3 Science Templates 10 3 1 CRIRES obs jitter 10 4 Nighttime Calibration Templates TBW 10 5 Daytime Calibration Templates TBW 11 CRIRES wavelength configuration vil 34 34 35 35 36 37 38 44 44 45 45 46 CRIRES User Manual VLT MAN ESO 14500 3486 1 1 Introduction The high resolution infrared echelle spectrometer of the VLT CRIRES is built by ESO CRIRES provides in the 1 Bum spectral range a resolving power of 10 with a 0 2 x 50 slit Signal to noise and spatial resolution is optimized with an adaptive optics AO system 1 1 CRIRES The cryogenic high resolution IR Echelle Spectrometer CRIRES has been conceived for the VLT in order to exploit the enormously enhanced sensitivity provided by a dispersive instrument with a large detector array at an 8m telescope The gain entails a quantitative and qualitative improvement of the observational capabilities It can boost all scientific applications aiming at fainter objects higher spatial extended sources spectral and temporal resolution The cryogenic echelle will provide e High resolution spectroscopy in the 1 5 um range at the VLT
5. 3417 787 3423 209 3442 081 3447 058 3465 218 3469 941 3487 360 16 1 i 3455 110 tbd 3409 708 3429 090 3434 461 3453 153 3458 082 3476 059 3480 733 3497 968 16 0 n 3532 635 tbd 3479 729 3497 974 3503 022 3520 560 3525 176 3541 983 3546 344 3562 395 16 0 i 3532 635 tbd 3490 351 3508 414 3513 411 3530 764 3535 331 3551 951 3556 263 3572 125 16 1 n 3610 160 tbd 3561 717 3578 486 3583 114 3599 154 3603 365 3618 656 3622 613 3637 132 16 1 i 3610 160 tbd 3571 378 3587 960 3592 536 3608 387 3612 548 3627 647 3631 554 3645 881 15 2 n 3644 994 tbd 3582 400 3603 897 3609 861 3630 635 3636 119 3656 143 3661 356 3680 599 157 2731 3644 994 tbd 3595 059 3616 370 3622 281 3642 866 3648 298 3668 130 3673 291 3692 340 15 1 n 3727 094 tbd 3668 500 3688 676 3694 264 3713 695 3718 816 3737 478 3742 326 3760 191 15 1 i 3727 094 tbd 3680 296 3700 280 3705 814 3725 052 3730 119 3748 585 3753 381 3771 046 15 1 n 3809 194 tbd 3755 050 3773 754 3778 924 3796 862 3801 579 3818 728 3823 173 3839 507 15 1 i 3809 194 tbd 3765 887 3784 395 3789 509 3807 249 3811 911 3828 859 3833 250 3849 382 15 2 n 3891 294 tbd 3842 193 3859 228 3863 923 3880 170 3884 429 3899 867 3903 855 3918 464 15 2 i 3891 294 tbd 3851 945 3868 779 3873 417 3889 461 3893 664 3908 897 3912 831 3927 235 14 2 n 3906 556 tbd 3839 546 3862 56
6. http www eso org paranal sciops The procedure for CRIRES does not deviate from the standard operations Visitors should be aware that about 30 minutes of their time will be taken for calibrations for each scientific target for which the users do not observe a telluric standard the observatory staff will do SO 71 3 The influence of the Moon Moonlight does not noticeably increase the background in any of the CRIRES modes so there is no need to request dark or gray time for this reason However it is recommended not to observe targets closer than 30 to the moon to avoid problems linked to the telescope guiding active optics system The effect is difficult to predict and to quantify as it depends on too many parameters Just changing the guide star often solves the problem Visitors are encouraged to carefully check their target positions with respect to the Moon at the time of their scheduled observations Backup targets are recommended whenever possible and users are encouraged to contact ESO in case of severe conflict i e when the distance to the Moon is smaller than 30 Visitors can use the tools that are available at http www eso org observing support html select the link airmass which is under User Support Tools to help determine the distance between targets and the moon for given dates However the moon may affect the quality of the adaptive optics correction if the source used for wavefront sensing is fainter than R
7. x50 field of view of the slit should be marked The OB names for PSF calibration stars should be prefixed with the string PSF 30 e The magnitude of the brightest object in all fields including standard stars should be ex plicitly given in the README file or otherwise indicated on the Finding Charts 31 1 Observing with CRIRES at the VLT 7 1 Overview As for all ESO VLT instruments users prepare their observations with the P2PP software Acqui sitions observations and calibrations are coded via templates Sec 10 and two or more templates make up an Observing Block OB OBs contain all the information necessary for the execution of an observing sequence CRIRES and the telescope are setup according to the contents of the OB They are executed by the instrument operator The CRIRES Real Time Display RTD is used to view the raw frame as well as the reconstructed images During acquisition sequences it is mostly used in slit viewer mode for proper centering of the targets in the slit Scientific exposures are typically checked in the raw frame display mode in order to view spectral features Beside an overview of the instrument set up the wavefront pupil as well as other information on the AO system can be displayed on a separate screen Daytime calibrations are executed the following morning by observatory staff 7 2 Visitor Mode Operations Information policy on the Visitor Mode operations at the VLT are described at
8. 5120 810 5127 526 5151 978 5158 324 5181 677 11 0 i 5138 378 tbd 5076 859 5103 139 5110 409 5135 657 5142 300 5166 481 5172 755 5195 833 11 1 n 5243 698 tbd 5172 764 5197 310 5204 088 5227 577 5233 745 5256 146 5261 945 5283 225 11 1 i 5243 698 tbd 5186 917 5211 194 5217 894 5241 109 5247 203 5269 327 5275 052 5296 053 11 2 n 5349 018 tbd 5284 944 5307 219 5313 351 5334 539 5340 085 5360 160 5365 340 5384 200 11 2 i 5349 018 tbd 5297 623 5319 621 5325 675 5346 582 5352 053 5371 847 5376 952 5395 628
9. The first step removes telluric features with what is commonly called a telluric standard the second step removes the spectral features of the telluric standard that are imprinted onto the science spectrum because of the first step and the third step sets the absolute scale with what one may call a spectroscopic flux standard In general the spectroscopic standard and the telluric standard are the same star but this does not need to be the case The most prominent features in IR spectra are the telluric lines of the Earth s Atmosphere Unfor tunately many of the telluric lines do not scale linearly with airmass so it is necessary to observe a standard at the same airmass and with the same instrument setup as that used for of the science target Furthermore the strength of the telluric lines varies with time so it is also necessary to observe the standard soon after or soon before the science target The spectrum of the telluric standard is divided directly into that of the science target Ideally the spectrum of the telluric standard should be known so that features belonging to it can be removed However this is not normally the case so one has to use standards in which the spectrum is approximately known In general we use either hot stars or solar analogs as telluric standards and generally these stars are selected from the Hipparchus Catalog The spectra of hot stars those hotter than B4 are relatively featureless and are well f
10. This instrument employs the largest available grating for a spectral resolving power of 10 for 2 pixel Nyquist sampling with a 0 2 slit e Spectral coverage maximized through four 1024 x 1024 pixel InSb detector arrays in the focal plane e Spectral imaging using a 50 long slit e Adaptive Optics to maximize SNR and spatial resolution Functionally the instrument can be divided into four units 1 The fore optics section provides for field de rotation cold pupil and field stops curvature sensing adaptive optics and slit viewing 2 The prism pre disperser isolates one echelle order and minimizes the total amount of light entering into the high resolution section 3 The high resolution section comprises the collimator the echelle which is tilt tuned for wave length selection the camera providing the 0 1 pixel scale and the detectors 4 Thecalibration unit outside the cryogenic environment contains light sources for flux wavelength calibration and detector flat fielding 1 2 Science drivers The IR spectrograph will make previously inaccessible phenomena and objects available for spec troscopic studies Some high lights are e Extra solar planets radial velocities spectroscopy of CO CH CRIRES User Manual VLT MAN ESO 14500 3486 2 e Solar system Giant planets Titan Hi CH4 CHs NH3 HCN Terrestrial planets CO HCL HDO H320 Mars imaging spectroscopy of CO depletion a
11. 0 i 1130 443 OH Lines 1116 833 1122 648 1124 256 1129 841 1131 311 1136 659 1138 047 1143 150 49 0 n 14534513 OH_Lines 1136 141 1142 133 1143 790 1149 549 1151 064 1156 582 1158 014 1163 283 49 0 i 1153 513 OH Lines 1139 630 1145 561 1147 202 1152 899 1154 398 1159 854 1161 270 1166 476 48 0 n 1177 545 OH Lines 1159 816 1165 930 1167 622 1173 499 1175 046 1180 677 1182 138 1187 516 48 0 i 1177 545 OH Lines 1163 377 1169 430 1171 104 1176 918 1178 448 1184 016 1185 461 1190 774 47 0 n 1202 599 OH Lines 1184 498 1190 741 1192 468 1198 468 1200 047 1205 797 1207 289 1212 779 47 0 i 1202 599 OH Lines 1188 134 1194 314 1196 023 1201 959 1203 521 1209 206 1210 681 1216 106 46 0 n 1228 743 OH Lines 1210 253 1216 630 1218 394 1224 523 1226 136 1232 009 1233 533 1239 141 46 0 i 1228 743 OH Lines 1213 967 1220 279 1222 025 1228 089 1229 684 1235 491 1236 998 1242 539 45 0 n 1256 048 OH_Lines 1237 153 1243 670 1245 473 1251 736 1253 384 1259 386 1260 943 1266 675 45 0 i 1256 048 OH Lines 1240 948 1247 399 1249 183 1255 380 1257 011 1262 945 1264 484 1270 148 44 0 n 1284 595 OH_Lines 1265 275 1271 938 1273 782 1280 186 1281 871 1288 007 1289 600 1295 460 44 0 i 1284 595 OH Lines 1269 155 1275 751 1277 576 1283 912 1285 579 1291 646 1293 221 1299 011 43 1 n 1299 404 OH_Lines 1278 837 1285 919 1287 881 1294 701
12. 017 893 56 0 i 009 324 OH_Lines 997 148 002 350 003 789 1008 786 010 100 014 885 1016 126 020 692 55 0 n 027 676 OH_Lines 1012 167 017 516 018 996 1024 137 025 490 030 415 1031 693 036 397 55 0 i 027 676 OH_Lines 1015 282 020 577 022 042 1027 127 028 466 033 336 1034 599 039 246 54 0 n 046 707 OH_Lines 1030 917 036 363 037 869 1043 103 044 481 049 496 1050 797 055 586 54 0 i 046 707 OH_Lines 1034 088 039 479 040 970 1046 149 047 511 052 470 053 756 058 488 53 0 n 066 456 OH_Lines 1050 373 055 920 057 455 1062 786 064 189 069 297 070 622 075 500 53 0 i 066 456 OH_Lines 1053 604 059 095 060 613 1065 887 067 275 072 325 073 636 078 455 52 0 n 086 965 OH_Lines 1070 579 076 230 077 794 1083 225 084 655 089 859 091 210 096 179 52 0 i 086 965 OH_Lines 1073 870 079 464 081 012 1086 385 087 799 092 945 094 280 099 191 51 0 n 108 278 OH_Lines 1091 576 097 336 098 930 1104 466 05 923 11 228 12 605 17 670 51 0 i 108 278 OH_Lines 1094 931 100 633 102 210 1107 687 09 128 14 374 15 734 20 739 50 0 n 130 443 OH_Lines 1113 413 119 286 120 912 1126 557 28 042 33 452 34 855 40 021 50 0 i 130 443 OH_Lines 1116 833 122 648 124 256 1129 841 31 311 36 659 38 047 43 150 49 0 n 153 513 OH Lines 1136 141 142 133 143 790 1149 549 51 064 56 582 58 014 63 283 49 0 i 153 513 OH_Lines 1139 630 145 561 147 202 1152 899 54 398 59 854 61 270 66 476 48 0 n 177 545 OH_Lines 1159 816 165 930 167 622 1173 499 75 046 80 677 82 138 87 516 48 0 i 177 545 OH_L
13. 15 mag In these cases reducing the lunar illumination FLI constraint to approximately 0 7 and increasing the distance to the Moon to approximately 50 degrees is generally adequate Even here it is important not to over specify the constraints as this reduces the chances of the Observing Block to be executed 32 7 4 Target Acquisition Schematic description of the sequence of events occurring during the target acquisition The acquisition sequence for observation with AO is the following Preset the telescope to the target coordinates offset the telescope to the AO guide star Interactively allow to re center the AO guide star Close the loop and offset the telescope back to the target Interactively allow to re center the target in the slit The acquisition sequence for observation without AO is the following Preset the telescope to the target coordinates Flatten the Deformable Mirror using the calibration fiber Interactively allow to re center the target in the slit If requested offset from the centered object e g to point to a faint target 7 5 Offset conventions and definitions CRIRES follows the standard astronomical offset conventions and definitions All offsets are given in arc seconds but the reference system can be chosen to be the sky Alpha Delta or the Detector X Y For a position angle of 0 the reconstructed image on the RTD will show North up and East left The positive position angl
14. 1864 185 1873 445 1875 851 1884 711 30 1 n 1905 477 tbd 1878 424 1887 770 1890 354 1899 317 1901 673 1910 240 1912 460 1920 619 30 1 i 1905 477 tbd 1883 838 1893 086 1895 642 1904 505 1906 834 1915 300 1917 494 1925 551 29 1 n 1926 919 tbd 1896 527 1906 991 1909 890 1919 969 1922 625 1932 305 1934 820 1944 087 29 1 i 1926 919 tbd 1902 646 1913 011 1915 882 1925 860 1928 489 1938 067 1940 555 1949 719 29 1 n 1971 161 tbd 1943 177 1952 845 1955 517 1964 788 1967 226 1976 088 1978 384 1986 824 29 1 i 1971 161 tbd 1948 778 1958 344 1960 987 1970 155 1972 564 1981 322 1983 591 1991 925 28 1 n 1995 763 tbd 1964 291 1975 127 1978 128 1988 566 1991 316 2001 340 2003 945 2013 541 28 1 i 1995 763 tbd 1970 628 1981 361 1984 333 1994 666 1997 388 2007 307 2009 883 2019 372 28 1 n 2041 535 tbd 2012 554 2022 566 2025 333 2034 935 2037 459 2046 637 2049 015 2057 756 28 1 i 2041 535 tbd 2018 354 2028 261 2030 998 2040 493 2042 988 2052 058 2054 407 2063 039 27 1 n 2069 708 tbd 2037 077 2048 312 2051 424 2062 246 2065 098 2075 491 2078 192 2088 141 27 1 i 2069 708 tbd 2043 647 2054 776 2057 858 2068 571 2071 394 2081 678 2084 349 2094 188 27 1 n 2117 119 tbd 2087 066 2097 449 2100 318 2110 275 2112 892 2122 409 2124 876 2133 940 48
15. 684 1680 508 1682 564 1690 037 1691 974 1699 086 33 1 n 1693 283 tbd 1666 552 1675 756 1678 305 1687 170 1689 506 1698 020 1700 232 1708 383 33 1 i 1693 283 tbd 1671 935 1681 051 1683 576 1692 352 1694 664 1703 088 1705 276 1713 336 33 1 n 1732 302 tbd 1707 700 1716 200 1718 549 1726 700 1728 843 1736 634 1738 653 1746 072 33 1 i 1732 302 tbd 1712 624 1721 035 1723 358 1731 418 1733 536 1741 235 1743 230 1750 556 32 1 n 1746 214 tbd 1718 654 1728 144 1730 772 1739 912 1742 320 1751 098 1753 379 1761 783 32 1 i 1746 214 tbd 1724 204 1733 603 1736 206 1745 254 1747 638 1756 323 1758 579 1766 889 32 1 n 1786 421 tbd 1761 053 1769 817 1772 240 1780 644 1782 853 1790 887 1792 969 1800 619 32 1 i 1786 421 tbd 1766 130 1774 802 1777 198 1785 509 1787 693 1795 631 1797 688 1805 243 31 1 n 1802 562 tbd 1774 118 1783 912 1786 624 1796 057 1798 543 1807 602 1809 956 1818 629 31 1 i 1802 562 tbd 1779 846 1789 546 1792 232 1801 571 1804 031 1812 995 1815 323 1823 899 31 1 n 1844 029 tbd 1817 846 1826 892 1829 392 1838 067 1840 347 1848 639 1850 788 1858 685 31 1 i 1844 029 tbd 1823 086 1832 037 1834 510 1843 088 1845 342 1853 536 1855 659 1863 457 30 1 n 1862 667 tbd 1833 282 1843 399 1846 202 1855 947 1858 515 1867 874 1870 306 1879 266 30 1 i 1862 667 tbd 1839 199 1849 220 1851 995 1861 643
16. CRIRES corrects a turbulent wavefront and provides diffraction limited images at the focal plane The overall sensitivity thereby is improved by about a factor two for point sources To highlight the advantage of combining MACAO and CRIRES a PSF is shown in Fig 3 in AO open loop uncorrected and closed loop where the PSF is reconstructed from wavefront measurements The non circular PSF in open loop is due to the very short integration time used Figure 3 PSF without left and with right AO correction for a short integration time 3 1 Introduction The following section provides only a introduction in the field of adaptive optics and atmospheric turbulences and essentially taken from the NACO user manual For further reading see for example Adaptive optics in astronomy Rodier 1999 Cambridge University Press or Introduction to adaptive optics Tyson 2000 Bellingham SPIE 3 1 1 Atmospheric turbulence The VLT has a diffraction limited resolution of 1 22 A D 0 07 arcsec at A 2 2um But the resolution is severely limited by atmospheric turbulence to A ro 1 arcsec where ro is the Fried parameter It is directly linked to the strength of the turbulence and depends on the wavelength as A For average observing conditions ro is typically 60cm at 2 2 jum Temperature inhomogeneities in the atmosphere induce temporal and spatial fluctuations in the air refractive index and therefore cause fluctuations in the optical p
17. H K H K gt gt 15 Please note The coordinates of the telescope guide star the target and the natural guide star of the AO system should be measured in the same consistent coordinate system with an accuracy of a small fraction of the CRIRES field of view For bright natural guide stars NGS the AO system will detect in closed loop the small offsets of the NGS and correct it with a tip tilt movement of the deformable mirror NGS parameters The parameters for the AO guide star are a logical flag Science Target AO Guide Star and the coordinates of the AO guide star in RA and DEC for the equinox we 40 presume the value given for the target coordinates Furthermore the approximate size of the AO guide star 0 for point sources only specify the size if you expect it to contributed significantly with respect to the seeing and the approximate color of the AO guide star are to be selected These parameters are required to properly setup the AO system with respect to aperture size of the WFS and differential atmospheric refraction between the visual light WFS and the IR spectrograph For any NGS fainter than 11 or 12 magnitudes it is mandatory that the telescope guide star coordinates are given by the user and aligned defined in the same reference system as the AO guide star Telescope Guide Star Selection SETUPFILE The reason for this is that slight inaccuracies 2 in the telescope and or AO guide star coordinates could not b
18. LJ TORGI 3HR 30 Figure 11 Expected CRIRES sensitivity S N versus magnitude have been calculated for 1 hour integration time on a point source conservatively based on the acceptance measurements of com ponents and the expected detector performances The graphs for H and K nearly overlap During comissioningl we reached for mx 13 a S N of 25 19 Figure 12 First light Begin End Begin End Begin End Begin End NAME Reference File name Detector Detector Detector Detector Detector Detector Detector Detector wave Wavelength spectral 1 1 2 2 3 3 A 4 4 length nanometer reference ID nm 59 0 n 958 003 OH Lines 943 523 948 517 949 899 954 698 955 962 960 560 961 754 966 145 59 0 i 958 003 OH Lines 946 432 951 375 952 743 957 491 958 740 963 287 964 466 968 805 58 0 n 974 520 OH Lines 959 796 964 875 966 280 971 160 972 445 977 121 978 334 982 799 58 0 i 974 520 OH Lines 962 754 967 781 969 171 974 000 975 270 979 893 981 093 985 504 57 0 n 991 617 OH Lines 976 641 981 806 983 235 988 199 989 506 994 262 995 496 000 038 57 0 i 991 617 OH Lines 979 649 984 762 986 177 991 088 992 380 997 082 998 302 002 789 56 0 n 009 324 OH Lines 994 087 999 342 000 796 1005 847 007 176 012 016 1013 272
19. celestial target coordinates The position angle on the sky is given in the standard astronomical convention N 0 NE 45 E 90 in degrees Note that for PA 0 North up East left the slitlets are oriented East West i e you will coarsely sample the field in the North South direction 250 100 25 mas per spaxel and obtain a finer sampling of the field in East West direction 125 50 12 5 mas per spaxel Also for PA 0 the slitlet number 1 will lie at the top of the detector high y Differential tracking is only available for the telescope There is no differential tracking between the natural guide star and the target Accordingly the adaptive optics loop can be only closed on the moving target and not on background stars The value is to be given in units of arcseconds s For service mode observations an ephemerides file needs to be provided Please consult the P2PP manual concerning the format and submission procedure Telescope guide stars are either selected from the CATALOG s available at the telescope or selected by the users if the option SETUPFILE was selected Telescope offset RA DEC to sky These keywords define the position where the sky field is to be observed if set to values 0 The sky exposure is taken before starting the interactive target identification If the value is set to 0 the step is skipped and the overhead time is shortened It may not be the best choice to skip the sky for faint targets of J
20. given in the following table acquisition templates functionality comment CRIRES ifs acq NGS Interactive Natural Guide Star Ac recommended quisition science templates CRIRES ifs obs GenericOffset IFS with user defined offsets night calibration templates CRIRES ifs cal StandardStar Standard star calibration observa calibration plan tion day time calibration templates CRIRES ifs cal Darks Darks calibration calibration plan Most users can prepare the complete observation runs with templates marked as recommended The calibration templates marked as calibration plan are executed by the observatory staff without being specifically requested during the phase 2 observation preparation The observatory will guarantee that these basic calibration observations are taken within the framework of the calibration plan A typical observation block with natural guide star adaptive optics in a normal field would consist of the following templates CRIRES ifs acq NGS natural guide star acquisition CRIRES ifs obs xxx staring nodding along perpendicular to the slit Calibration templates could be of interest in the case that special night time standards or calibrations are requested Night time arcs and flats are typically not needed even though they are offered for the time being The usual rules for OBs apply you can include only 1 acquisition template it can be followed by several science templates changes to set u
21. guide star V 10 guide star V 13 ER V 13 V 16 x NS V 16 S y s ost no AO o B 2 7807 o 0 6l 3 0 6 ES 300 5 a gt a m 0 4 D u 8 E Us o 8 a 02r E di 0 1 0 1 0 L L L 1 L 1 1 0 L 1 1 1 1 1 L 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 1 1 12 02 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 1 1 1 2 seeing seeing M band 0 2 slitwidth 09r J fraction of energy available for the spectrograph 0 4 0 3 foo RA 1 0 2 V 10 guide star 1 V 13 01r sac VS 16 sl no AO 0 1 1 1 l f 1 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 1 1 1 2 seeing Figure 9 The fraction of energy available for the spectrograph in the 0 2 slit as a function of seeing is shown for the J top left K top right and M bottom band for guide star magnitudes V 10 12 16 and without AO correction CRIRES can be used without adaptive optics guide star in which case the AO module just acts as relay optics and the spatial resolution is given by the natural seeing The full power of the instrument is achieved when an adaptive optics guide star is available For best correction the star should be brighter than R 11 mag However the AO can work and will provide a moderate image quality improvement with stars as faint as R 16 17 mag in the best seeing conditions Ideally the AO guide star should be as close as possible to the scientific target if not the science target itself
22. n 3070 481 tbd 3019 879 3037 278 3042 101 3058 890 3063 317 3079 472 3083 674 3099 171 18 1 i 3070 481 tbd 3030 092 3047 333 3052 112 3068 740 3073 125 3089 118 3093 276 3108 609 18 0 n 3140 120 tbd 3093 090 3109 308 3113 796 3129 386 3133 489 3148 429 3152 307 3166 575 18 0 i 3140 120 tbd 3102 532 3118 589 3123 031 3138 457 3142 516 3157 291 3161 124 3175 224 18 1 n 3209 760 tbd 3166 742 3181 633 3185 744 3199 987 3203 726 3217 303 3220 817 3233 708 18 1 i 3209 760 tbd 3175 321 3190 046 3194 110 3208 185 3211 879 3225 286 3228 755 3241 475 17 1 n 3251 445 tbd 3197 887 3216 303 3221 408 3239 177 3243 864 3260 962 3265 409 3281 812 17 1 i 3251 445 tbd 3208 696 3226 945 3232 003 3249 603 3254 244 3271 171 3275 572 3291 801 17 0 n 3324 833 tbd 3275 038 3292 210 3296 962 3313 468 3317 812 3333 631 3337 736 3352 843 17 0 i 3324 833 tbd 3285 035 3302 037 3306 740 3323 072 3327 370 3343 013 3347 071 3362 001 17 1 n 3398 221 tbd 3352 653 3368 427 3372 781 3387 869 3391 830 3406 212 3409 934 3423 591 49 17 11 3398 221 tbd 3361 740 3377 339 3381 643 3396 553 3400 466 3414 669 3418 343 3431 819 16 1 n 3455 110 tbd 3398 229
23. not have IR magnitudes which means that IR magnitudes have to be taken from 2MASS DENIS or even inferred from the spectral type Such an extrapolation leads to an uncertainty of 5 20 in the absolute flux calibration If users wish to have a more certain absolute flux calibration they should provide their own standards and should have included these observations in their requested time in Phase 1 Alternatively if the broad band magnitudes of the object are known the absolute flux calibration can be derived by convolving the measured spectrum with the broad band filter curves In this case the IR magnitude of the standard is irrelevant only the spectral type is important 5 Performance Compared with most infrared astronomy programs so far at the VLT a larger fraction of the CRIRES science is likely to depend less on detection limit and more on the achievement of high signal to noise ratios on relatively bright objects stars and or accurate radial velocities e g for detecting exo planets Sensitivity expectations before first light for CRIRES are given in figure 11 Note that K band performance and off course L and M are more or less limited by the thermal background whereas in J and H the detector performance is setting the limits This means that J and H band could profit from technical development in the field of detectors whereas for A gt 2um the performance is no longer strongly affected by the detector characteristics On the
24. of CRIRES and by nodding with an amplitude smaller than the slit length 50 the object is still in the slit while the sky is measured Otherwise sky measurements have to be obtained from offset fields and the acquisition templates allow for several option see Sec 10 The frequency of sky measurements depend on the band more frequent in J H less in K and on the accuracy on which one wants to subtract them Sky variations are of order a few minutes Thus sky measurements could vary from 120s to 600s It is recommended to choose the same DIT and vary NDIT only if noise characteristics are not important for your subtraction 6 2 OBs and P2PP CRIRES follows very closely the template design set by other VLT instruments such as ISAAC SINFONI and NACO see also Sect 10 28 6 2 1 Templates Here we give an overview of the CRIRES templates A more detailed description can be found in Sec 10 Acquisition Two acquisition templates allow to distinguish between the cases of observing without AO acq noA0 and with a Natural Guide Star NGS for AO corrections acq NGS The former resembles other VLT acquisition templates except for two particularities e It allows to flag whether the Deformable Mirror DM should be flatten after the telescope preset before the observations this is highly recommended in order to obtain the best image quality e lt allows an end offset to be made i e to acquire a bright star and perform
25. resolving power of 50000 In case the highest possible resolution of nominally 100000 is important to reach for a particular observing proposal a slit width of 0 2 can be used only at the expense of drastically reduced efficiency and therefore much longer exposure times This issue is subject to further instrument characterisations in future comissioning runs but can also not propserly considered in the ETC for the time being Efficiency of CRIRES versus slit width Efficiency of CRIRES measured with HIP102497 0 20 e a 0 10 Efficiency e photon 2 12 2 13 2 14 2 16 2 17 2 18 2 15 1 Wavelength micron Slit width oresec Figure 16 Overall system efficiency The wavelength dependence of the efficiency for a particular wavelength setting is shown left for different slit widths The peak efficiency as a function of slit widths is given on the right 5 5 Stabillity For wavelength calibration the stabillity and reproducibillity of the different mechanical functions of CRIRES are important The positioning reproducibillity of the prism as a function of read out of the encoder shows a peak to peak variation of 1 5pixels This reproducibility can be reduced to an rms of 0 44 pixels by introducing the stabilisation times of 10s In Fig 17 the positioning reproducibility of the prism is shown as a function of mean values of the encoder reads which are averaged over a period of 10s Similar figures are found for the positionin
26. size 404 pixels Communicating Sky Flat file to the Slit viewer DCS and RTD Starting CRIRES Interactive Acquisition Done TCS offset 0 000 5 000 Check that a new image is displayed on RTD Figure 18 BOB window interface of acquisition template 41 42 Step 1 Center NGS Open Loop 1 Adjust DIT INT and FILTER for the Slit Viewer Detector Check with the Slit Viewer RTD 2 If needed repeat sky flat and 1 3 Center object via RTD Click on the object via the Slit Viewer RTD 1 Slit Viewer Detector 2 Slit viewer Sky Flat 3 Center Object via RTD DIT 5 000 OFFA 0 0 Click to center object NDIT 3 opp 11 0 SV Filter Take Sky Flat Action Next step AO loop will be closed SETUP SV RTD Next Step gt Step 2 Fine Center NGS Closed Loop 1 Adjust DIT INT and FILTER for the Slit Viewer Detector Check with the Slit Viewer RTD 2 If needed repeat sky flat and 1 3 Center object via RTD Click on the object via the Slit Viewer RTD 1 Slit Viewer Detector 2 Slit viewer Sky Flat 3 Center Object via RTD DIT 5 000 OFFAJ 0 0 Click to center object NDIT 1 OFFD 11 0 SV Filter lf Take Sky Flat Action Next step Offset to Target and Center Target SETUP SWERTE lt Step Back Next Step gt Figure 19 Pop of window of step 1 and 2 durin
27. those for staring observations The offsets are along the slit positions and are randomly distributed around a fixed offset position and defined by the parameter INS NODTHROW from the original target telescope position The dimension of the random positions are along the slit and set by the parameter Jitter box width around the initial sky position and therefore identical to those of the target jitter box The following two items are already defined by the acquisition task i Derotation can be done in sky or elevation mode and is given by INS DROT MODE ii The positon angle of the slit is given by TEL ROT OFFANGLE and is defined as the negative of the astronomical position angle P A on the sky TEL ROT OFFANGLE P A and is measured counter clockwise from North to East CRIRES obs _jitter IFS with jitter and nodding Parameters to be specified Parameter Range Default P2PP Label INS WLEN ID isf NODEFAULT Wavelength ID 58 1 n SEQ NDIT 1 10000 NODEFAULT NDIT read outs SEQ JITTER WIDTH 0 8 0 Jitter box width in arcsec SEQ NABCYCLES 0 100 0 Number of AB cycles 0 for staring on source INS NODTHROW 0 60 0 Nodding offset along the slit Hidden parameters SEQ POISSON 1 100 10 SEQ RETURN TF T Return to Origin T F DPR CATG SCIENCE SCIENCE Data product category DPR TECH IFU NODDING IFU NODDING Data product technique DPR TYPE OBJECT OBJECT Data product type 45 10 4 Nig
28. to the number of lenslet in the lenslet array the number of actuators behind the DM and the rate at which WF errors can be measured processed and corrected the server loop bandwidth The performance of an AO system is also linked to the observing conditions The most important parameters are the seeing the brightness of the reference source used for WFS and the distance between the reference source and the object of interest In case of good conditions and a bright nearby reference source the correction is good and the resulting point spread function PSF is very close to the diffraction limit A good correction in the K band typically corresponds to a SR larger than 30 At shorter wavelengths particularly in the J band or in the case of poor conditions or a faint distant reference source the correction is only partial the Strehl ratio may only be a few percent 3 2 Hardware description The MACAO system for CRIRES is based on a 60 actuator deformable mirror inserted in a so called relay optics These optics and the wavefront sensor optics are mounted on a breadboard which is located between the Nasmyth focus and the spectrometer It is about 1 5m wide and a top view of the warm optics overlayed by the optical path is shown in Fig 5 the assembly of the deformable mirror is displayed in Fig 6 yy oa Set se y ia LES Nasmyth focus _ Y pip ta nyt F TR en gt Optical derotator E d Dichroic Analysis tool
29. 0 3868 944 3891 184 3897 055 3918 490 3924 070 3944 669 14 2 i 3906 556 tbd 3853 098 3875 912 3882 239 3904 276 3910 092 3931 321 3936 846 3957 236 14 1 n 3993717 tbd 3930 957 3952 567 3958 553 3979 366 3984 850 4004 838 4010 031 4029 165 14 1 i 3993 717 tbd 3943 591 3964 996 3970 924 3991 529 3996 957 4016 734 4021 871 4040 792 14 1 n 4080 878 tbd 4022 843 4042 890 4048 432 4067 660 4072 715 4091 097 4095 862 4113 371 14 1 i 4080 878 tbd 4034 459 4054 297 4059 778 4078 793 4083 791 4101 957 4106 664 4123 956 14 2 n 4168 039 tbd 4115 350 4133 628 4138 667 4156 101 4160 671 4177 239 4181 520 4197 200 14 2 i 4168 039 tbd 4125 816 4143 879 4148 857 4166 073 4170 584 4186 932 4191 154 4206 614 13 2 n 4208 742 tbd 4136 654 4161 413 4168 282 4192 207 4198 522 4221 580 4227 583 4249 740 13 2 i 4208 742 tbd 4151 231 4175 775 4182 583 4206 289 4212 545 4235 382 4241 325 4263 257 13 1 n 4301 487 tbd 4233 926 4257 189 4263 632 4286 038 4291 941 4313 458 4319 049 4339 645 13 1 i 4301 487 tbd 4247 526 4270 569 4276 949 4299 131 4304 974 4326 264 4331 794 4352 160 13 1 n 4394 231 tbd 4331 696 4353 298 4359 269 4379 987 4385 435 4405 243 4410 377 4429 245 13 1 i 4394 231 tbd 4344 213 4365 589 4371 496 4391 985 4397 370 4416 946 4422 018 4440 652 13 2 n 4486 975 tbd 4430 120 4449 842
30. 00 600 and 900s may be used 5 4 System efficiency and throughput The overall efficiency of CRIRES is measured on spectrophotometric calibration standard stars The photometric flux of such a star in Jy F is converted to the flux in photons s pixel Fy It holds usnig SI units that 1 26 Cp A ue RA F LE DU E where is the photon energy Are is the telescope are and AA A R is the dispersion in units of um pixel The conversion gain after multiplication by the interpixel capacitance of 0 9 yields 7 73 e ADU The overall efficiencyis defined as the ratio of e s pixel as measured on the detector divided by the theoretical expected photon flux photons s pixel arrivnig above the Earth s atmosphere 24 In Fig 16 the overall efficiency as a function of slit width for order 26 at 2150nm is shown together with the peak efficiency versus slit width Below a slit width of 0 3 the efficiency in this measurement is below 3 One of the main reason is that for short coherence times 2ms the AO does not work effectively and most of the energy of the star is in the seeing disk not entering the spectrograph Opening the slit to 0 7 increases the throughput to 12 and for widely opened slit it reaches 17 Repeatnig this measurement with better seeing conditions was not possible during the first comissionnig run For this period we therefroe strongly encourage observers to use a slit width of 0 4 at the expense of a reduced
31. 1 format with a spacing between arrays of only 264 pixels To do this each array was removed from its original LCC package by Raytheon and glued on the ESO mount consisting of a multilayer Aluminum nitride ceramic carrier On the mount are a copper block for the cooling braid connections a 3 point kinematic mount a temperature sensor and a heating resistor Also there is a connector to the two layer Manganin boards which interface each detector to a preamplifier board equipped with 64 cryogenic operational amplifiers As the slit is only 512 pixels long there is no need to require 4 usable quadrants per array The actual arrays selected will be optimally oriented as shown in Fig 2 The array on the right is one remaining from the first ESO funded foundry run in the 90th and exhibits the lowest dark current measured so far in any array at ESO 14 electrons hour with drift correction using dead pixels with open indium bumps despite or maybe due to the presence of several pronounced cracks This array has been included specifically to ensure the best possible noise performance at the shortest wavelengths The arrays will be read out using standard ESO IRACE controllers 4 having 64 channels 4 x 16 for the science arrays and 32 channels for the slit viewing camera 3 Adaptive optics system The adaptive optics system of CRIRES is discussed by Paufique et al 2004 SPIE 5490 15 The multi applications curvature adaptive optics system MACAO for
32. 1296 498 1303 049 1304 751 1311 021 43 1 i 1299 404 OH Lines 1282 980 1289 994 1291 936 1298 688 1300 466 1306 947 1308 631 1314 831 43 1 n 1329 534 OH Lines 1310 622 1317 156 1318 962 1325 227 1326 874 1332 863 1334 415 1340 117 43 1 i 1329 534 OH_Lines 1314 407 1320 872 1322 658 1328 854 1330 482 1336 399 1337 932 1343 563 42 1 n 1330 350 OH_Lines 1309 300 1316 548 1318 556 1325 537 1327 376 1334 081 1335 823 1342 241 42 1 i 1330 350 OH_Lines 1313 540 1320 719 1322 706 1329 617 1331 438 1338 071 1339 794 1346 140 42 1 n 1361 181 OH Lines 1341 823 1348 511 1350 360 1356 773 1358 459 1364 589 1366 177 1372 015 42 1 i 1361 181 OH Lines 1345 698 1352 315 1354 144 1360 485 1362 152 1368 209 1369 778 1375 542 41 1 n 1362 806 OH Lines 1341 249 1348 672 1350 728 1357 877 1359 761 1366 627 1368 411 1374 983 41 1 i 1362 806 OH_Lines 1345 590 1352 942 1354 978 1362 056 1363 920 1370 713 1372 478 1378 977 41 1 n 1394 372 OH_Lines 1374 546 1381 396 1383 289 1389 857 1391 584 1397 862 1399 489 1405 468 41 1 i 1394 372 OH_Lines 1378 514 1385 292 1387 164 1393 659 1395 366 1401 570 1403 177 1409 081 40 1 n 1396 885 OH Lines 1374 795 1382 401 1384 508 1391 834 1393 764 1400 800 1402 628 1409 363 40 1 i 1396 885 OH Lines 1379 244 1386 777 1388 864 1396 116 1398 026 1404 988 1406 796 1413 456 40 1 n 1
33. 1528 078 37 1 n 1545 075 OH_Lines 1523 120 1530 705 1532 802 1540 075 1541 987 1548 940 1550 742 1557 362 37 1 i 1545 075 OH Lines 1527 514 1535 020 1537 093 1544 286 1546 176 1553 046 1554 826 1561 363 36 1 n 1552 138 OH Lines 1527 618 1536 061 1538 399 1546 531 1548 674 1556 483 1558 513 1565 989 36 1 i 1552 138 OH_Lines 1532 556 1540 918 1543 234 1551 284 1553 405 1561 132 1563 139 1570 532 36 1 n 1587 982 OH_Lines 1565 421 1573 216 1575 370 1582 844 1584 809 1591 954 1593 805 1600 609 36 1 i 1587 982 OH_Lines 1569 937 1577 649 1579 780 1587 171 1589 113 1596 173 1598 002 1604 721 35 1 n 1596 497 OH_Lines 1571 283 1579 964 1582 369 1590 731 1592 935 1600 966 1603 052 1610 740 35 1 i 1596 497 OH_Lines 1576 360 1584 959 1587 341 1595 619 1597 800 1605 746 1607 810 1615 412 35 1 n 1633 341 OH Lines 1610 138 1618 155 1620 370 1628 057 1630 078 1637 425 1639 329 1646 327 35 1 i 1633 341 OH_Lines 1614 782 1622 714 1624 905 1632 506 1634 504 1641 765 1643 646 1650 555 34 1 n 1643 466 OH Lines 1617 516 1626 451 1628 926 1637 532 1639 800 1648 065 1650 213 1658 125 34 1 i 1643 466 OH_Lines 1622 742 1631 592 1634 043 1642 562 1644 807 1652 985 1655 109 1662 933 34 1 n 1681 367 OH Lines 1657 485 1665 736 1668 016 1675 928 1678 008 1685 571 1687 531 1694 733 34 1 i 1681 367 OH Lines 1662 265 1670 429 1672
34. 21 626 21 1 n 2751 827 tbd 2714 987 2727 741 2731 261 2743 459 2746 661 2758 287 2761 296 2772 335 21 1 i 2751 827 tbd 2722 333 2734 945 2738 425 2750 478 2753 642 2765 123 2768 093 2778 984 20 1 n 2762 976 tbd 2717 406 2733 075 2737 418 2752 538 2756 525 2771 074 2774 858 2788 815 20 1 i 2762 976 tbd 2726 604 2742 131 2746 434 2761 409 2765 358 2779 761 2783 506 2797 315 20 0 n 2826 108 tbd 2783 776 2798 374 2802 414 2816 446 2820 140 2833 587 2837 077 2849 920 20 0 i 2826 108 tbd 2792 275 2806 728 2810 726 2824 611 2828 265 2841 563 2845 013 2857 705 20 1 n 2889 240 tbd 2850 549 2863 943 2867 640 2880 451 2883 814 2896 025 2899 185 2910 778 20 1 i 2889 240 tbd 2858 264 2871 509 2875 164 2887 823 2891 146 2903 204 2906 323 2917 762 19 1 n 2908 616 tbd 2860 662 2877 151 2881 722 2897 631 2901 828 2917 138 2921 120 2935 806 19 1 i 2908 616 tbd 2870 341 2886 680 2891 209 2906 967 2911 122 2926 279 2930 220 2944 751 19 0 n 2974 851 tbd 2930 293 2945 659 2949 911 2964 681 2968 569 2982 723 2986 396 2999 914 19 0 i 2974 851 tbd 2939 239 2954 452 2958 660 2973 275 2977 121 2991 118 2994 750 3008 109 19 1 n 3041 085 tbd 3000 346 3014 449 3018 342 3031 830 3035 372 3048 229 3051 556 3063 764 19 1 i 3041 085 tbd 3008 470 3022 416 3026 264 3039 594 3043 092 3055 789 3059 073 3071 119 18 1
35. 396 656 2406 725 23 1 n 2429 833 tbd 2391 555 2404 735 2408 385 2421 080 2424 424 2436 617 2439 784 2451 456 23 1 i 2429 833 tbd 2399 262 2412 317 2415 932 2428 499 2431 810 2443 873 2447 007 2458 549 23 1 n 2485 138 tbd 2449 863 2462 050 2465 418 2477 104 2480 177 2491 348 2494 243 2504 883 23 1 i 2485 138 tbd 2456 923 2468 981 2472 313 2483 870 2486 907 2497 947 2500 807 2511 314 22 1 n 2511 493 tbd 2470 043 2484 295 2488 246 2501 998 2505 625 2518 859 2522 301 2534 997 22 1 i 2511 493 tbd 2478 409 2492 532 2496 447 2510 068 2513 660 2526 761 2530 168 2542 729 22 0 n 2569 189 tbd 2530 699 2543 973 2547 645 2560 404 2563 763 2575 990 2579 163 2590 840 22 0 i 2569 189 tbd 2538 427 2551 568 2555 204 2567 828 2571 150 2583 241 2586 378 2597 918 22 1 n 2626 885 tbd 2591 726 2603 897 2607 257 2618 898 2621 954 2633 050 2635 922 2646 456 22 1 i 2626 885 tbd 2598 736 2610 772 2614 094 2625 597 2628 616 2639 573 2642 408 2652 802 21 1 n 2631 236 tbd 2587 823 2602 750 2606 888 2621 291 2625 090 2638 950 2642 555 2655 852 21 171 2631 236 tbd 2596 585 2611 377 2615 477 2629 743 2633 505 2647 226 2650 794 2663 949 21 0 n 2691 531 tbd 2651 212 2665 116 2668 964 2682 329 2685 847 2698 655 2701 979 2714 211 21 0 i 2691 531 tbd 2659 307 2673 073 2676 881 2690 106 2693 586 2706 252 2709 538 27
36. 429 223 OH Lines 1408 904 1415 924 1417 864 1424 596 1426 365 1432 799 1434 467 1440 594 47 40 1 i 1429 223 OH_Lines 1412 971 1419 917 1421 836 1428 492 1430 241 1436 599 1438 246 1444 297 39 1 n 1432 712 OH Lines 1410 061 1417 861 1420 021 1427 533 1429 512 1436 726 1438 601 1445 507 39 1 i 1432 712 OH_Lines 1414 623 1422 348 1424 487 1431 923 1433 882 1441 020 1442 874 1449 703 39 1 n 1465 860 OH_Lines 1445 024 1452 223 1454 213 1461 115 1462 930 1469 528 1471 238 1477 521 39 1 i 1465 860 OH_Lines 1449 195 1456 317 1458 285 1465 111 1466 905 1473 425 1475 114 1481 318 38 1 n 1470 425 OH Lines 1447 184 1455 187 1457 403 1465 111 1467 142 1474 544 1476 467 1483 553 38 1 i 1470 425 OH_Lines 1451 865 1459 791 1461 986 1469 616 1471 626 1478 950 1480 852 1487 859 38 1 n 1504 425 OH Lines 1483 045 1490 432 1492 473 1499 557 1501 419 1508 189 1509 944 1516 391 38 1 i 1504 425 OH_Lines 1487 324 1494 633 1496 653 1503 657 1505 497 1512 188 1513 921 1520 288 37 1 n 1510 177 OH Lines 1486 314 1494 531 1496 806 1504 720 1506 806 1514 406 1516 381 1523 657 37 1 i 1510 177 OH_Lines 1491 120 1499 258 1501 512 1509 346 1511 410 1518 930 1520 883
37. 4455 279 4474 092 4479 024 4496 905 4501 525 4518 449 13 2 i 4486 975 tbd 4441 415 4460 905 4466 276 4484 855 4489 723 4507 367 4511 924 4528 612 12 2 n 4561 918 tbd 4483 930 4510 717 4518 148 4544 030 4550 861 4575 805 4582 297 4606 263 12 2 i 4561 918 tbd 4499 699 4526 252 4533 617 4559 262 4566 030 4590 732 4597 160 4620 883 12 1 n 4660 759 tbd 4587 605 4612 795 4619 772 4644 032 4650 424 4673 722 4679 775 4702 075 12 1 i 4660 759 tbd 4602 330 4627 282 4634 190 4658 208 4664 535 4687 586 4693 574 4715 625 12 1 n 4759 601 tbd 4691 804 4715 223 4721 696 4744 158 4750 064 4771 541 4777 107 4797 566 12 1 i 4759 601 tbd 4705 375 4728 549 4734 953 4757 167 4763 005 4784 230 4789 730 4809 934 12 2 n 4858 442 tbd 4796 685 4818 105 4824 011 4844 447 4849 805 4869 231 4874 251 4892 642 12 2 i 4858 442 tbd 4808 957 4830 126 4835 960 4856 142 4861 431 4880 601 4885 553 4903 687 11 2 n 4927 739 tbd 4840 417 4870 379 4878 696 4907 686 4915 342 4943 318 4950 605 4977 525 11 2 i 4927 739 tbd 4858 104 4887 815 4896 061 4924 794 4932 381 4960 097 4967 315 4993 972 11 1 n 5033 059 tbd 4950 666 4979 001 4986 856 5014 190 5021 398 5047 694 5054 532 5079 751 11 1 i 5033 059 tbd 4967 289 4995 366 5003 147 5030 219 5037 357 5063 387 5070 155 5095 104 11 0 n 5138 378 tbd 5061 406 5087 950 5095 295
38. 77 372 015 42 1 i 361 181 OH_Lines 1345 698 352 315 354 144 1360 485 362 152 368 209 1369 778 375 542 41 1 n 362 806 OH Lines 1341 249 348 672 350 728 1357 877 359 761 366 627 1368 411 374 983 41 1 i 362 806 OH_Lines 1345 590 352 942 354 978 1362 056 363 920 370 713 1372 478 378 977 41 1 n 394 372 OH_Lines 1374 546 381 396 383 289 1389 857 391 584 397 862 1399 489 405 468 41 1 i 394 372 OH_Lines 1378 514 385 292 387 164 1393 659 395 366 401 570 1403 177 409 081 20 Figure 13 First light image of the sky The OH doubled at 1708 6nm is resolved at the resolution of CRIRES Two field selectors allow to pick the AO guide star within a 2 x1 field centered on the spec trograph field However only under good atmospheric conditions a star at a distance gt 10 will provide a significant image quality improvement Under Excellent conditions bright stars as far as 20 30 can still be used to provide a mild improvement of the image quality The brightness of the AO guide star The intra and extra focal pupil of the AO guide star is imaged on a lens let array and each lens let fed to an Avalanche Photo Diode APD that ultimately forward its signal to the Real Time Computer RTC The Flux on the APD is limited to 1 million counts in order not to damage the devices and thus stars brighter than R 11 mag are dimmed by a set of neutral density filters for up to 9 mag Hence stars brighter than R 2 m
39. Lines 979 649 984 762 986 177 991 088 992 380 997 082 998 302 1002 789 56 0 n 1009 324 OH_Lines 994 087 999 342 1000 796 1005 847 1007 176 1012 016 1013 272 1017 893 56 0 i 1009 324 OH Lines 997 148 1002 350 1003 789 1008 786 1010 100 1014 885 1016 126 1020 692 55 0 n 1027 676 OH Lines 1012 167 1017 516 1018 996 1024 137 1025 490 1030 415 1031 693 1036 397 55 0 i 1027 676 OH Lines 1015 282 1020 577 1022 042 1027 127 1028 466 1033 336 1034 599 1039 246 54 0 n 1046 707 OH Lines 1030 917 1036 363 1037 869 1043 103 1044 481 1049 496 1050 797 1055 586 54 0 i 1046 707 OH Lines 1034 088 1039 479 1040 970 1046 149 1047 511 1052 470 1053 756 1058 488 53 0 n 1066 456 OH_Lines 1050 373 1055 920 10577455 1062 786 1064 189 1069 297 1070 622 1075 500 53 0 i 1066 456 OH_Lines 1053 604 1059 095 1060 613 1065 887 1067 275 1072 325 1073 636 1078 455 52 0 n 1086 965 OH Lines 1070 579 1076 230 1077 794 1083 225 1084 655 1089 859 1091 210 1096 179 52 0 i 1086 965 OH_Lines 1073 870 1079 464 1081 012 1086 385 1087 799 1092 945 1094 280 1099 191 51 0 n 1108 278 OH_Lines 1091 576 1097 336 1098 930 1104 466 1105 923 1111 228 1112 605 1117 670 51 0 i 1108 278 OH Lines 1094 931 1100 633 1102 210 1107 687 1109 128 1114 374 1115 734 1120 739 50 0 n 1130 443 OH Lines 1113 413 1119 286 1120 912 1126 557 1128 042 1133 452 1134 855 1140 021 50
40. The pre disperser collimator mirror is also equipped with piezos to allow fine active control of the spectrum position using atmospheric spectral lines for programs requiring the highest spectral resolution In order to meet the stringent thermal and stray light requirements the entire optical system is enclosed within a light shield plus two AlMg radiation shields with mirror finish quality Care is also being taken e g by using an intermediate connector to avoid light leaks at the penetrations of cables Essentially the only light path into the high resolution section of the instrument is through the narrow order isolation slit at the exit of the prism pre disperser light sensitive length of the array 133 542 mm 4946 pixel gap of 7 15 mm 1024 pixel 27 um 0 5 mm for mounting Ape ver um f i ims E 27 648 mm 0 5 mm for mounting 283 pixel e ALADDIN III ALADDIN II Assy 411731 ALIRD04 low dark current 4x10 e s ALADDIN III ALADDIN III Slit Assy 411730 Assy 415477 Figure 2 Layout of the 4 Aladdin detector mosaic of the spectrometer array The fifth Aladdin detector of the slit viewer camera is not shown 2 3 Detectors CRIRES uses 5 Raytheon 1024x1024 pixel InSb Aladdin arrays one for the slit viewer and 4 in the spectrograph focal plane which provides a useful optical field of 135 x 21mm The four science arrays are packed in a 4x
41. Uncorrected image Deformable mirror Real Time Computer 4 i Wavefront Beam splitter Serv f Y AO corrected image Tip tilt mirror 2 Corrected wavefront el 44 Camera high resolution image Figure 4 Principle of Adaptive Optics Note that in practice and contrary to this schematic design CRIRES has no dedicated Tip Tilt mirror but performs low and high order corrections with a single deformable mirror mounted on a tip tilt stage An AO system is a servo loop system working in closed loop The DM flattens the incoming WF and the WFS measures the residual WF error A commonly used WFS is the Shack Hartmann WFS cf NACO However CRIRES as well as the other ESO MACAO systems relies on a Curvature WFS The curvature sensor is designed to measure the WF curvature as opposed to the WF slope This is achieved by comparing the plane irradiance distributions of two planes placed behind and before the focal plane In practice a variable curvature mirror membrane is placed in the telescope focus By vibrating inside and outside focus blurred pupil images can be imaged on a detector array for CRIRES a lenslet array feeding avalanche photo diodes APDs The modulation frequency of the membrane corresponds to the temporal sampling frequency of the WFS The difference between the inside and outside pupil image measures the local WF curvature 10 The performance of an AO system is related
42. a known offset to the real target The acquisition for AO using a natural guide star has also a few particularities concerning infor mation on the AO guide star e It requires the absolute coordinates of the AO guide star Unless you tick the box Target AO Guide Star in which case it will use the target coordinates as the one for the AO guide star e It also asks for the B R color of the AO guide star This is used to compute the guiding wavelength for the field selector holding the AO guide star Which in turn is used to correct for atmospheric refraction effects Roughly speaking the field selector takes over the function of the telescope guiding in AO mode by locking on the AO star for longer observations at high airmass or during acquisition the offset due to atmospheric refraction at the different wavelength visible on the AO system vs NIR on the spectrograph needs to be taken into account e Finally it requires the FWHM of the AO Guide star in order to optimize a diaphragm in the AO system This diaphragm is set as a function of the seeing such as to optimize the amount of light received from the object with respect to the amount of background light from the sky If your object is a point source leave this to zero only the seeing will be taken into account Only if your AO guide star is significantly extended with respect to the seeing i e comparable to the seeing value this optimization parameter will have a noticeable e
43. able on performance and observing templates The manual reflects knowledge gathered during laboratory tests and is in this respect to be considered in some aspects to be preliminary Therefore we strongly recommend to consult http www eso org instruments crires for additional information and updates Further support during proposal preparation and OB submission please contact ESO s User Support Group usg help eso org 1 4 Glossary Active optics is the active control of the primary and secondary mirror of the telescope It is performed using a telescope guide star Adaptive optics is the correction of wavefront errors induced by atmospheric turbulence The wave front is measured from the AO guide star and the corrections are sent to the deformable mirror within the instrument Although the instrument can run in closed loop without the active optics system controlling the primary and secondary mirror However one gets better adaptive optics performance if the active optics system of the telescope is running Part CRIRES hard ware 2 Instrument design The CRIRES instrument design is presented by Moorwood et al 2003 SPIE 4841 1592 a summary is presented in the following subsections 2 1 Optics The optical layout of CRIRES is shown in Fig 1 Light enters from the direction of the telescope Nasmyth focus either via the telescope or from a calibration unit consisting of an integrating sphere illuminated by continuum or line la
44. ag cannot be used as AO guide star Stars brighter than R 17 mag will not improve further the performance of the AO system Good correction under average seeing are still obtained with stars as faint as R 14 mag Any star fainter than this will require good to excellent atmospheric conditions to provide an image quality improvement Service mode we do not recommend to prepare observations with an AO guide star fainter than R 14 mag unless you provide a very restricted constraint set that forces the observatory staff to observe your target under the very best atmospheric conditions which in turn reduces dramatically your chances of seeing this observation ever performed Visitor mode the above recommendation is also valid but for cases in which you have selected a very faint AO guide star you could in parallel prepare OBs with no AO acquisition i e if the atmospheric conditions are not sufficient to close the AO loop on your guide star you would fall back on the same observation without AO The color of the AO guide star The color of the guide star is important for two reasons 1 The APD response curve extends from 450nm to 900nm and peaks around 650nm Thus the R band magnitude provides only a crude estimate of the number of photons that the wave front sensor WFS will collect The B R color provides a color term with which we can correct the R band magnitude to get a better estimate of this number Very crudely the magnitude co
45. and usually closer than 10 Depending on the atmospheric conditions atmospheric coherence length the AO guide star could be chosen as far as 30 for the AO system to still provide a mild improvement of the encircled energy 15 Part ll Observing with CRIRES 4 Introduction 4 1 Atmospheric Transmission The transmission of the Earth s atmosphere in the J H K L and M bands is shown in Fig 10 The amount of telluric absorption varies with zenith distance and precipitable water vapor Lu Y L L L 11500 12000 12500 13000 13500 Wavelength angstroms E WWW a L L 1 1 20000 21000 22000 23000 24000 Wavelength angstroms Figure 10 Atmospheric transmission in the J H K L and M bands These graphs are based on FTS data at the McMath Pierce Solar Telescope on Kitt Peak produced by NSF NOAO 4 2 Background Emission There are two regimes in the sky background emission Below 2 2 jum the sky emission is dom inated by OH emission taking place at an altitude of 80 km Detailed sky spectra with OH line identifications are available on the ISAAC web page Beyond 2 2 um the thermal background dominates The thermal background consists of atmospheric and telescope emission 16 4 3 Spectrophotometric Calibration Calibration of spectroscopic data in the IR is a complicated procedure that requires care It is generally done in three steps
46. ath This leads to random phase delays that corrugate the wavefront WF The path differences are to a good approximation achromatic Only the phase of the WF is chromatic The correlation time of WF distortions is related to the average wind speed V in the atmosphere and is typically of the order of ro V 60ms at 2 2 um for V 10m s 3 1 2 Adaptive Optics A technique to overcome the degrading effects of atmospheric turbulence is real time compensation of the deformation of the WF by adaptive optics AO Figure 4 The wavefront sensor WFS measures WF distortions which are processed by a real time computer RTC The RTC controls a deformable mirror DM to compensate the WF distortions The DM is a continuous thin plate mirror mounted on a set of piezoelectric actuators that push and pull on the back of the mirror Because of the significant reduction in the WF distortions by continuous AO correction it is possible to record near diffraction limited images with exposure times that are significantly longer than the turbulence correlation time The residual error from the WF compensation WF error directly determines the quality of the formed image One of the main parameters characterizing this image quality is the Strehl ratio SR which corresponds to the amount of light contained in the diffraction limited core relative to the total flux Observed object Plane wavetront E Atmospheric turbulence Corrugated wavefront Y
47. dwarfs are commonly used Given the expected sensitivity for CRIRES see below we have scanned the Hipparchus Main Catalog to select potential spectroscopic standards using the following selection criteria lt 30 stars B8 or earlier with V lt 4 09 and stars with spectral types B8 GO with V lt 4 8 9 This left us with a list of 466 stars bright enough to be used up to A 5jum for wavelengths up to the L band there are about 900 stars earlier then A1 which can be used In some critical areas it will be necessary to measure stellar spectral templates and this is another good reason to restrict the number of grating settings supported by the observatory Please decide carefully about which star is best suited for your program Although the observatory will automatically observe a telluric standard for service programs we cannot guarantee that we will make the best choice as this depends on the science users wish to do If you think that a specific spectral type suits your program better than others we recommend that you submit calibration 17 OBs The observatory selects telluric standards from four catalogs the IRIS Photometric Standards the MSSSO photometric standards a composite list of bright spectroscopic standards and the Hipparchus Catalog The majority of the standards come from the Hipparchus Catalog Although the Hipparchus Catalog is an excellent source of telluric standards for ISAAC most of the stars in the catalog do
48. e corrected for by the field selector for brighter magnitudes the field selector drags back and centers the AO guide star For normal field not for globular clusters not for the galactic center the coordinates of the UCAC2 catalog should be accurate enough The coordinates of the science target and NGS should be also known in the absolute celestial coordinate system in case of a UCAC2 telescope guide star Blind Offsets In case of blind offset acquisitions the coordinates of the reference star must be entered into the target package of p2pp The offsets are defined from the reference star to the target positive offsets for targets North East of the reference stars The relative offset between reference star and target should be accurately known to about a small fraction of the field of view File Configure Interface Errors OBs file gt bob gt CRIRES Next observation blocks m CRIRES TEST 0 A Moorwood 17 F CRIRES spec acq NGS CRIRES NGS acquisition DETI PIESO NDIT 1 DPR CATG ACQUISITION TECH SPEC TYPE OBJECT INS DROT MODE ELEV DROT POSANG 0 0 SLIT WIDTH 10 AUT RAT ITS KAMNIT IEEE Ej Template log messages Done Slit Viewer detector RTD initialised Sending Instrument Data Sending setup Checking guiding state Checking Active Optics started Correction reached Sky flat file Setting Slit viewer DCS guiding parameters
49. e is defined from North to East Note that the templates use cumulative offsets That is your position at a given time is derived from the sum of all offsets specified so far in the template For example the series of offsets 0 10 0 10 brings you back to the original position for the last exposure This could have been the definition of a series in which we define an exposure on object followed by two sky exposures at 10 of the original position before pointing back on the object for the fourth exposure 7 6 Overheads The telescope and instrument overheads are summarized below 33 Hardware Item Action Time minutes Paranal telescopes Preset 6 Paranal telescopes Offset 0 25 CRIRES Acquisition without AO 3 CRIRES CRIRES CRIRES CRIRES Acquisition with AO Acquisition target with without AO Instrument setup grating change Science exposure read out per DIT gt 1min 2 Aa DIT NDIT 4 Aa DIT a NDIT 2 5 1 Note table needs to be updated For acquisition with AO DIT and NDIT refer to the ones requested for the AO natural guide star NGS Instrument set up is usually absorbed in the telescope preset Changing grating within an OB is very slow 2 5 min on average Acquisition without AO takes 3 minutes mostly used to drive in the calibration fiber close the AO loop once in order to flatten the deformable mirror and drive out the fiber In this way the optimal image q
50. e optimal setting In Fig 15 the noise histogram and map of detector 2 is shown as a function of operating temperature Best compromise is found operating detectors at at 27 5K Summary of mean detector parameters Dark current 0 04 eis Gain 8 e ADU Read out noise 10e rms Saturation level 120000e Operating Temperature 27 5K Read out settings There are only two detector read out parameters to be adjusted by the observer DIT and NDIT As the dark depend on DIT setting we recommend to use e In general if there are no starvation or saturation risk on medium bright stars use DIT 30s 23 Noise Histogram of CRIRES science detector Aladdin 2 10 Number of Pixels a ot A ka Ei L 10 150 o s 8 Reodout noise erms Figure 15 For science detector 2 we show on the left the noise histogram for different operating temperatures left and on the right the noise map at detector temperature of 32 top 30 middle and 26K bottom Note that the cosmetic qualitv improves bv lowering the temperature while the read out noise increases Best compromise is found operating the detectors at 27 5K e For short exposures on standard stars brighter than J H K 8 10 mag DITs of 1s and NDIT between 2 and many gt 10 e for long exposures on faint targets in which no saturation risk is given DIT depending on the frequency on which the sky is obtained so for faint targets DIT of 120 3
51. e plate scale on binary stars Measure transmission profile of the prism 36 10 CRIRES template reference All scientific and calibration observations with ESO instruments are prepared as observing blocks OBs with the phase 2 proposal preparation tool P2PP The scheduling of these OBs is then done on the site with the broker of observing block BOB and p2pp in visitor mode and with bob and the observation tool OT during service mode observation runs Observing blocks consist of the target information a small number of user selected templates the constraints sets and the scheduling informations The observing templates which are described below are lists of keywords parameters of the respective templates to define the configuration and setup to be used for the respective observations Parameters are user defined or hidden to the user to simplify the appearance of the parameter lists Hidden parameters cannot be changed by the users but by the instrument operators Since the hidden parameters will be rarely changed during science observation runs we do not provide an explanation here in the template reference section Unlike for other instruments there are only a few templates available for CRIRES There exists only one acquisition template which however is a rather complex tool box operated by the instrument operator The user has only to specify input parameters A summary of supported templates together with the short description is
52. e reviewed the IOP can execute them by clicking on SETUP The window include a short message of the action describing the next acquisition step The interface is coded so that the IOP is able to go to the next step but it also able to return back to the previous step without aborting the sequence The four main acquisition steps are e Center NGS in open AO loop Fig 19 e Fine center NGS and close AO loop Fig 19 e Center target in closed loop Fig 20 e Adjust slit viewer guiding Fig 20 The main function of the acquisition template is to preset the telescope to setup the instrument and to move the target to the center of the field of view Furthermore the acquisition sequence will start in case it is requested the adaptive optics in closed loop mode or flatten the deformable mirror which is required to achieve good image quality in open loop no AO Optionally a sky subtraction frame can be taken in an offset field for faint targets Finally some adjustment to the SV camera can be performed In the following the acquisition template keywords are described 38 10 2 Parameter description CRIRES 0 01 CRIRES_acq tsf To be specified Parameter Range Default Label SEQ TIME 60 3600 NODEFAULT Total integration time sec TEL TARG ALPHA ra TEL TARG DELTA dec TEL TARG EQUINOX 2000 0 TEL TARG ADDVELALPHA 0 0 RA additional tracking velocity TEL TARG ADDVELDELTA 0 0 DEC additional trackin
53. e wavefront which provides the wavefront error The fibers drive the signal from the fiber feed module to the APD cabinet mounted to the instrument The APD counts are recorded by the APD counter module synchronously with the membrane signal The front end assembly of the fibre bundle is shown in Fig 8 3 2 3 Control loop The oscillating membrane produces a signal modulated proportional to the local wavefront curva ture This signal collected by avalanche photo diodes APD is sent to the real time computer 13 Figure 8 Front end assembly of the 60 fibre bundle which guide the light to the sensors The RTC computes this modulation and retrieves the voltages to be applied to the mirror and tip tilt mount to optimally compensate for the local curvature measured For this an precise cal ibration of the system is required membrane mirror synchronisation membrane curvature pupil alignment interaction matrices being the main ones 3 2 4 Limitations The membrane mirror curvature represents an optical gain for the aberrations measurements A way to increase the performance of the system is therefore to increase the curvature of this mirror But increasing this requires increasing as well the field of view of the wavefront sensor optics and some other non linear effects can degrade the estimate of the curvature For the same reason extended sources will affect the quality of curvature measurement and lead to a different optimal gai
54. ens Ewe e B 212 Adaptive OPUES lt s sda saadi inata haya 3484408455 3 2 Hardware description ENT EN ee RR AE 4 B RACE d 321 The corrective optics 2 2 oos REG RE ERE RS Sea The Wavefront Sensors 2426242642 mu VOY Y Re ee eRe eG 3 23 Control IGBD sse es s eek EEE E eS a Be ee HE 324 Limitations egen Gece ee wae Se OER RR ESR REE 4S 3 3 AO performance uuu aa debated SES X RRR xo Re SEEDER eR Rm CA SWUM ce a 6 6 Bob ESE ASAD SHRED BREEDS SEE EARS EH Il Observing with CRIRES 4 Introduction 4 1 Atmospheric Transmission 2 ceso bere Gees ree GO eee he 4 2 Background Emission i 424546544 asta OE a EE SCA 4 3 Spectrophotometric Calibration 5 Performance BI AO G de SaS oc PEER b A ana AAA AA e 5 2 Spectrograph modes y ias e belek woe Ges A 5 3 Detector characteristics does soe dad B dom b ER de Re X SR RO RUE OS 5 4 System efficiency and throughput 2 2 2 00 2 ee ee BS NEN uuu unde E Se ae ES ees x3 ems Na 5 6 Limiting magnitudes vi Q M Lo I Ooo a co oco oo CO CRIRES User Manual VLT MAN ESO 14500 3486 5 7 The Exposure Time Calculator 5 8 Proposal form 246 estaa 6 Preparation of observing blocks 6 1 Information required 52 Obs and P2PP xx xs 6 21 Templates 6 2 2 Observing Blocks OBs DAS P2PP 2 644 94433 563 Finding Charts cs kaw ki eas 7 Observing with CRIRES at the VLT 7 1 Overview 0 7 2 Visitor Mode Operations
55. ffect Finally both acquisition templates will usually acquire during the acquisition sequence a sky image to be subtracted from the object image to enhance the contrast If your object is bright in the NIR e g K lt 10 mag this is not needed and you can save a bit of time by setting the Alpha and Delta offset to sky to 0 this will force the template to skip the sky measurement Observing The observing templates are standard if you have observed with other NIR instruments at the VLT or NTT They allow variations in the strategy of obtaining sky measurements Calibration Darks arc wavelength calibration and lamp flat field exposures are taken during daytime as part of the calibration plan see sect 9 If for a particular reason you wish to obtain arcs or lamps immediately after your exposure you can attach the template cal Nightcalib at the end of your OB However any kind of instrument 29 flexure in the spectral direction are very small If you wish to estimate exactly the image quality obtained on your AO guide star you can insert in your OB the template cal NGS immediately after your acquisition This will set back the AO guide star into the spectrograph field of view and obtain an image of the NGS which can later be used for performance PSF analysis Note that such an image is not taken by default during the acquisition unlike for NACO for ex ample Telluric standard stars are part of the calibrati
56. ffsets between images taken at the selected object and sky positions or offer the possibillity to perform staring observations The template will automatically take exposures in an ABBA sequence with the respective A object and B sky positions randomly jittered with respect to each other The common parameters of science templates are DIT and NDIT are the user defined integration time for the exposures of the target and the number of DITs to be integrated before writing the data to disk Number of AB or BA cycles defines how often the AB cycle is repeated Set to zero the template will just take exposures on source position A set to one will perform take a sequence AB and set to two will do ABBA object sky sky object For best sky subtraction the parameter should be set to values of one or larger 10 3 1 CRIRES_obs_jitter The science template CRIRES_obs_jitter follows the one of SINFONI called SINFONI_ifs obs FixedSkvOffset It moves the telescope alternatively between object and sky positions nodding but in one dimension which is along the slit The object positions are randomly distributed jittered around the object initial telescope position and within a box whose dimensions are set by the parameter Jitter box width in arcsec The jitter is only performed along the slit The size of the jitter box should be typically a few arcsec If set to zero no jitter will be performed The default parameters are
57. g execution of acquisition template 43 Step 3 Center Target Closed Loop 1 Adjust DIT INT and FILTER for the Slit Viewer Detector Check with the Slit Viewer RTD 2 If needed repeat sky flat and 1 3 Center object via RTD Click on the object via the Slit Viewer RTD 1 Slit Viewer Detector 2 Slit viewer Sky Flat 3 Center Object via RTD DIT 5 000 OFFA 0 0 NDITJ i OFFD 11 0 SV Filter Take Sky Flat Click to center object Action Next step Adjust guiding window size on RID SETUP DI lt Step Back Next Step gt Step 4 Slit viewer guiding 1 Adjust DIT INT and FILTER for the Slit Viewer Detector Check with the Slit Viewer RTD 2 If needed repeat sky flat and 1 3 Center object via RTD Click on the object via the Slit Viewer RTD 1 Slit Viewer Detector 2 Slit viewer Sky Flat 3 Center Object via RTD DIT 5 000 OFFAJ 0 0 NAT JS Click to center object NDIT i OFFD 11 0 SY Filter Il Take Sky Flat Action Adjust guiding window size on RTD when needed Next step Continue with template SETUP Sve lt Step Back OK gt Continue Figure 20 Pop of window of step 3 and 4 during execution of acquisition template 44 10 3 Science Templates Science observing templates provide various strategies for nodding between object and sky positions for jitter o
58. g reproducibility of the grating which shows a peak to peak variation of 2 5pixels and by introducing stabilisation times a rms reproducibility of 1 1pixels A FFT analysis classifies thsoe oscillations to have white noise characteristics also we will analyse this performance in more detail in the future The rms reproducibility of the positioning of the slit is 0 07 pixels and that of the piezo is 0 035pixels Demonstarting the superb stability of the piezo The good point is also that the oscillations noted by inspecting encoder values of the prism and grating are not directly coupled to the wavelength stabillity For example if one analysis the stabillity of lines one find a rms fluctuation of 0 33 pixels In general the calibration strategy is that the absolut wavelength calibration is performed by cross correlation of the observered sky lines with information provided by catalogs such as HITRAN or OH 25 line lists So wavelength calibration is aimed to be done from the data of a particular observations In the moment we cannot granty that this strategy is working for all offered wavelengths settings Reproducibility of Prism ofter waiting 10 s line postion pixel 4 2 0 2 4 meon encoder position steps Figure 17 Positioning reproducibility of a line centered on a specific detector pixel is shown as a function of mean values of the encoder reads Mean values are computed by averaging over a period of 10s The computed rms is 0 44
59. g veloc It TEL TARG WCONJY 0 300000 1 Sota ju flux in Jy or Jy arcsec at observing wave length TEL TARG HMAG 2 10 0 Source magnitude in H TEL TARG KMAG 2 10 0 Source magnitude in K TEL TARG VMAG 2 15 0 Source magnitude in V TEL ROT OFFANGLE 235 235 0 PA on sky deg TEL AG GUIDESTAR CATALOGUE SETUPFILE Get Guide Star from NONE CATALOGUE TEL GS1 ALPHA ra Guide star RA TEL GS1 DELTA dec Guide star DEC TEL SKY OFFALPHA 120 120 0 Tel offset RA to sky deg TEL SKY OFFDELTA 120 120 30 Tel offset Dec to sky deg SEQ NGS ISTARGET T F T Target is AO GS SEO NGS ALPHA ra RA of AO GS SEQ NGS DELTA dec Dec of AO GS SEQ NGS MAG 2 25 12 AO GS magnitude in R SEQ NGS COLOR 1 5 AO GS B R SEQ NGS FWHM 0 10 0 AO GS FWHM arcsec DET DIT isf Detector integration time s DET NDIT isf Number of integrations INS WLEN CATALOGUE SETUPFILE Order Sub order Nominal NONE CATALOGUE Interlaced e g interlaced 19 2 17 INS DROT MODE ELEV SKY STAT ELEV Mode of de rotation INS DROT POSANG 0 359 0 0 Position Angle on sky Hidden parameters SEQ PRESET T F T Telescope preset flag DPR CATG ACQUISITION Data product category DPR TYPE OBJECT Data product type l North 0 East 90 Parameter ranges for H K magnitudes needs to be determined according to slit viewer detector starvation or saturation limits respectively Parameter ranges fo
60. g web pages http www eso org observing observing html and http www eso org observing p2pp and http www eso org paranal sciops These web pages set the phase 2 policy and its information overrules this manual Unlike other VLT instruments OB preparation for CRIRES does not require specific software preparation tools 6 1 Information required The following information is required for a successful creation of CRIRES observing blocks e Target coordinates Also CRIRES has a slit viewer target coordinates should be as precise as possible e Observations with AO guide star target coordinates are offset from the AO guide star coordinates i e it is strongly recommended to obtain the AO guide star and target coordinates from the same catalog reference system Further the AO guide star coordinate should be accurate enough such that it is visible during the acquisition performed VLT absolute pointing accuracy is 1 2 e Observations without AO guide star there are two possibilities i to specify the telescope guide star in the acquisition template and provide target coordinates in the same reference system this will guarantee a pointing accuracy of typically 0 1 0 2 Or ii to point to a bright nearby star and perform an offset from this star at the end of your acquisition In this case coordinates of science target and bright star shall be from the same reference system e Sky measurements Using the long slit
61. httime Calibration Templates TBW There are xxxx templates available to calibrate during the night The StandardStar template is used to observe telluric standards of known JHK magnitudes to allow the removal of telluric features and to derive an estimate of the instrument response function for the flux calibration of the science data This template would be typically used by the observatory staff spart of the calibration plan unless there is a special request for a user selected standard In that case the user has to supply his her own standard using this template The PSF template is available to obtain an estimate of the instrument PSF by observing a user selected typically bright PSF reference star The StandardStar and PSF templates are identical to the GenericOffset template in keyword content and function There is furthermore an NGS template offered which will center the natural guide star NGS to the center of the image slicer to estimate the PSF by on axis observations of the NGS There are no parameters to be set in the template except the DIT NDIT and a fixed sky offset The template is only useful if target and NGS are not identical Attached lamp calibrations are also provided These templates will read the exposure times and lamp setups from a local data base Accordingly there is only one parameter left over the spectral dither flag which defines whether spectrally dithered calibration should be taken or not 10 5 Daytime Ca
62. ines 1163 377 169 430 171 104 1176 918 78 448 84 016 85 461 90 774 47 0 n 202 599 OH_Lines 1184 498 190 741 192 468 1198 468 200 047 205 797 1207 289 212 779 47 0 i 202 599 OH Lines 1188 134 194 314 196 023 1201 959 203 521 209 206 1210 681 216 106 46 0 n 228 743 OH Lines 1210 253 216 630 218 394 1224 523 226 136 232 009 1233 533 239 141 46 0 i 228 743 OH Lines 1213 967 220 279 222 025 1228 089 229 684 235 491 1236 998 242 539 45 0 n 256 048 OH_Lines 1237 153 243 670 245 473 1251 736 253 384 259 386 1260 943 266 675 45 0 i 256 048 OH_Lines 1240 948 247 399 249 183 1255 380 257 011 262 945 1264 484 270 148 44 0 n 284 595 OH Lines 1265 275 271 938 273 782 1280 186 281 871 288 007 1289 600 295 460 44 0 i 284 595 OH_Lines 1269 155 275 751 277 576 1283 912 285 579 291 646 1293 221 299 011 43 1 n 299 404 OH Lines 1278 837 285 919 287 881 1294 701 296 498 303 049 1304 751 311 021 43 1 i 299 404 OH_Lines 1282 980 289 994 291 936 1298 688 300 466 306 947 1308 631 314 831 43 1 n 329 534 OH_Lines 1310 622 317 156 318 962 1325 227 326 874 332 863 1334 415 340 117 43 1 i 329 534 OH_Lines 1314 407 320 872 322 658 1328 854 330 482 336 399 1337 932 343 563 42 1 n 330 350 OH Lines 1309 300 316 548 318 556 1325 537 327 376 334 081 1335 823 342 241 42 1 i 330 350 OH_Lines 1313 540 320 719 322 706 1329 617 331 438 338 071 1339 794 346 140 42 1 n 361 181 OH_Lines 1341 823 348 511 350 360 1356 773 358 459 364 589 1366 1
63. isitor mode Wave front Wave front sensor CRIRES User Manual VLT MAN ESO 14500 3486 iv telescope CRIIRIES de rotator integrating sphere e i Aw wavefront slit viewer sensor L pre disperser echelle gratin _ 3 mirror TMA 8 5 collimator camera Wavelength range Resolving power 2 pixels 10 Slit width Slit length Pixel scale Adaptive optics Calibration system Slit viewer Pre disperser Echele grating Polarimetry Detector science array 1 5um 0 2 pa 1 50 0 1 60 actuator curvature sensing NACAO system 2 balckbodies 2 spectral lamps gas cells 1k Aladdin III array filters 0 05 pixel scale ZnSe prism 40 x 20cm 31 6 lines mm 63 5 blaze circular using Fresnel rhomb and Wollaston prism 4096 x 512 pixels using 4 Aladdin III detectors CRIRES User Manual VLT MAN ESO 14500 3486 This page was intentionally left almost blank CRIRES User Manual VLT MAN ESO 14500 3486 Contents 1 Introduction CES 0 PCT 1 2 Seience v nuu Roo BE vox de se EEO 3 UE gos s 1 3 Structure and scope of the User Manual ln FOE o oaa poe ce chee mea beeen pea EES HEE SS CRIRES hard ware 2 Instrument design MI eee BS he eee we GRASS EE BES AS eG AS en LS E aw IOS os agoi eado ee BES WARS bee EE eed e A C Detectors o sa d ose eee a AA EE EEE Ee A oS ee A erg A 3 Adaptive optics system ely a EENEG 3 1 1 Atmospheric turbulence lt lt lt
64. it by blackbody curves So by knowing the spectral type of the star one uses a blackbody curve with the appropriate temperature to fit the continuum of the standard The spectra of stars that are cooler than AO start to have many more features and cannot be fit with a blackbody curve for wavelengths below 1 6 microns Unfortunately hot stars do contain some features usually lines of hydrogen and helium that can be difficult to remove If the region around the hydrogen and helium lines are of interest then one can also observe a late type star which should have weak hydrogen and helium lines This star is then used to correct for the helium and hydrogen absorption in the spectrum of the hot star Some hot stars also have emission lines or are in dusty regions These stars should be avoided The V I color of the star can be used as an indicator of dust For stars hotter than AO it should be negative And lastly hot stars tend to lie near the galactic plane so there may be situations where there are no nearby hot stars Solar analogs for the purpose of removing telluric features are stars with spectral type GOV to G4V These standards have many absorption lines in the IR particularly in the J band The features can be removed by dividing by the solar spectrum that has been degraded to the resolution of the observations In addition to hot stars and solar analogs IR astronomers have used other stellar types as telluric standards For example F
65. libration Templates TBW The day time calibration observations are typically prepared by the staff astronomers with an automatic tool calobBuild which will scan the headers of the frames taken during the nights Based on this data it will then define and sort the required sequence of calibration exposures according to the CRIRES calibration plan It is not foreseen that users will use any of the day time calibration templates below We only present these templates to provide a reference between the data files and the respective templates 11 CRIRES wavelength configuration 46 Begin End Begin End Begin End Begin End NAME Reference File name Detector Detector Detector Detector Detector Detector Detector Detector wave Wavelength spectral 1 1 2 2 3 3 4 4 length nanometer reference ID nm 59 0 n 958 003 OH Lines 943 523 948 517 949 899 954 698 955 962 960 560 961 754 966 145 59 0 i 958 003 OH_Lines 946 432 951 375 952 743 957 491 958 740 963 287 964 466 968 805 58 0 n 974 520 OH_Lines 959 796 964 875 966 280 971 160 972 445 977 121 978 334 982 799 58 0 i 974 520 OH_Lines 962 754 967 781 969 171 974 000 975 270 979 893 981 093 985 504 57 0 n 991 617 OH_Lines 976 641 981 806 983 235 988 199 989 506 994 262 995 496 1000 038 57 0 i 991 617 OH
66. mps for flat fielding and wavelength calibration There are four lamps 3200 K Halogen and 1000 K blackbody and spectral lamps with Neon and Krypton The integrating sphere provides uniform illumination of the entrance slit of the spectrometer and its flux can be adjusted by a moving baffle Higher accuracy wavelength calibration is achieved using sky lines or narrow absorption lines in the gas cells which can be inserted in the beam as shown The gas cell turret also contains a Fresnel rhombus or quarter wave plate whose insertion can be combined with that of a Wollaston prism for measuring circular polarisation The Fresnel rhombus is a two mirrors and a prism device which can be rotated to transform circular into linear polarisation however at the expense of a reduced filed of view from nominal 50 to 5 Following the calibration unit there is a 3 mirror de rotator which is used to counteract the telescope field rotation when making long slit observations In this way offsets of the source position due to different atmospheric diffraction in the optical and IR can be compensated and small mechanical instabilities can be corrected The de rotator allows to perform the nodding in the slit observing strategy Then comes the adaptive optics system used to concentrate the light at the 0 2 wide spectrograph slit The AO system comprises a 60 element deformable mirror mounted on a tip tilt stage on which is formed a pupil image by the two mirr
67. mputed by the RTC scales as RTCmag Rmag 2 8 1 65 B R l e Blue stars will provide more photons to the WFS The RTC estimates magnitudes for 21 stars with B R 1 7 e g K2V star 2 The color is also essential for atmospheric refraction compensation The WFS corrects the telescope guiding for the atmospheric refraction difference between its optical guiding wave length and the near infrared central wavelength of the spectrograph set up Once the response curve of the WFS is taken into account the optical guiding wavelength can be derived from the B R color as follows Guiding wavelength nm 590 40 B R 5 2 Spectrograph modes At the nominal spectral resolution of CRIRES typically 50 grating settings will be sufficient to cover the entire infrared spectrum accessible from the ground in the range of 0 95 lt A lt 5 2m Offered instrument wavelengths settings wavelength wavelengths ID However for this period only a subset of discrete settings will be supported by the observatory for science observations e allowed instrument wavelengths settings which could be commissioned for this period are given in Tab e Set ups will be done by using the instrument model to position the spectrum with the precision of typically a few pixels e In case that sky lines can be detected in starring frames they will be used to improve the absolute wavelength calibration by the pipeline However no
68. n In some extreme cases the system can be unable to close the loop extended 6 planetary nebula with a faint blue white dwarf in the middle or a faint star close to the Moon for example There is a trade off to do and an optimal optical gain to apply This optimal gain will depend mainly on the seeing size and marginally on the star magnitude and other factors This optimal gain is tabulated in the configuration of the software and is transparent for the user 3 3 AO performance The performance achieved by the MACAO system of CRIRES has been evaluated by laboratory simulations Two cases are distinguished i in closed loop with guide stars of various magnitudes and ii in open loop so without AO corrections The optimization was done over the encircled energy on a 0 2 slit representative of the available energy for the spectrograph The lab results demonstrate a weak gain in J and a strong factor 2 increase of the fraction of the energy available for the spectrometer in the K and M band respectively Fig 9 3 4 Summary The high resolution infrared echelle spectrometer of the VLT CRIRES provides in the 1 5um spectral range a resolving power of 10 for 2 pixel Nyquist sampling with a 0 2 x 50 slit Signal to noise and spatial resolution is optimized with an adaptive optics AO system 14 J band 0 2 slitwidth K band 0 2 slitwidth fa T Ir SE e E T 7 T E beg i
69. nstrument mounted turbomolecular pump connector flanges pressure gauges overpressure safety valve and the small temperature controlled cabinets housing the two sets of front end electronics for the detectors Underneath is the support the pre vacuum pump and alignment structure which also provides access to a port in the lower lid of the vacuum vessel through which the grating unit can be accessed and removed Inside the mirror optics and most of the mechanical structure is made of Aluminum alloy The TMA mirrors have a thin 30m nickel coating on the reflective surface which is diamond turned then conventionally polished and finally ion beam polished before gold coating Although nickel coating is usually applied on both sides we have found by modeling that although reducing bending this increases the total wavefront aberration compared with plating a single surface The remaining mirrors are being nickel plated diamond turned and hand post polished The only non reflecting optics in the system apart from the window is the ZnSe prism using for order sorting The thermal stability is stable within 0 1K and limit any variations of temperature gradients to lt 50 mK m hr To counter drifts due e g to the external diurnal temperature variations however active temperature control is also foreseen using heaters mounted on a ring whose temperature will be controlled to 0 1K and is connected to various points in the instrument by conducting braids
70. o input a typical DIT which for long exposures will probably be anything between 300 and 900s typically The output from the ETC summarize your input values and provides some output for which you should remember the following e The integration time is given on source depending on your technique to obtain sky measurements and accounting for overheads the total observing time will be much larger e The S N is given per spectral pixel not per resolution element i e to compute your S N for a resolution element make sure that you sum the right number of pixels typically 2 For more detailed information on ETC see online help provides as links from the ETC page 5 8 Proposal form For CRIRES proposals no specific input to the ESO proposal form is needed In particular as CRIRES can be used with and without AO guide star your target list will not be checked for valid AO guide stars as it is done e g for NACO However you are requested to state whether you will or will not use AO Choices of set ups are given below INSconfig CRIRES NGS provide HERE list of setting s J H K H K 7777 27 6 Preparation of observing blocks This sections guides through some details in preparing CRIRES observing blocks during ESO pro posal submission phase 2 Observations may either be submitted for service or visitor mode Familiarize yourself with some general information about phase 2 and submission of OBs by con sulting the followin
71. on plan for all your observations PSF standard stars are not If you wish to observe a PSF standard star prepare a corresponding OB with the template cal PSF 6 2 2 Observing Blocks OBs Any CRIRES science OB should contain one and only one acquisition template followed by a num ber of science templates CRIRES foresees two cases in which calibration templates can be attached to such science OBs The special nighttime calibrations cal Nightcalib that can be attached after every set up in the OB or preferably the OB should contain only one instrument set up and the Nightcalib template be attached to the end of the OB And _acq_NGS to be attached typically right after the acquisition template in order to record an image of the AO Natural Guide Star 6 2 3 P2PP Using P2PP to prepare CRIRES observations does not require any special functions Also no file has to be attached except for the finding chart all other entries are standard 6 3 Finding Charts In addition to the general instructions on finding charts and README files that are available at http www eso org observing p2pp the following is recommended e Ideallv the finding chart should show the filed in the NIR or at least in the red and the wavelength of the image should be specified in the FC or the README file The AO guide star if used should be clearly marked The bright star from which to offset if used should be clearlv marked The 0 2
72. or relay optics the dichroic window which transmits infrared light to the cryogenically cooled spectrograph while reflecting visible light to the wavefront sensor WFS which uses an avalanche photodiode APD detector and can be translated in x y at 0 5Hz to maintain object centering as determined by the slit viewer As far as possible the design of the AO system and its individual components have been copied from the MACAO system developed by ESO for VLTI and the SINFONI instrument Further details of the AO system can be found in Sect 3 of this manual The spectrograph itself is housed in a vacuum vessel Following the input window a pupil image is formed at the position of a cold stop which limits parasitic background and where the Wollaston prism can be inserted Light then either passes through the slit or is reflected to the slit viewing camera Light passing through the slit enters the prism spectrometer where it is dispersed and then exits through an output slit sized to limit the wavelength range passing into the high resolution section to a single order The high resolution spectrograph consists of a 40 x 20 cm 31 6 lines mm 63 5 blaze echelle grating plus a TMA three mirror anastigmat which acts first as a collimator and then as a camera to image the spectrum on the four Aladdin detectors which are used to make a 4096 x 512 pixel image of the spectrum telescope CRIRES de rotator integrating sphere Aw wavefront sli
73. other hand in this field the point source sensitivity approaches that of the lower resolution spectrograph ISAAC In this wavelength regime some projects which do not necessarily need the spectral resolution of CRIRES may still profit from the high spectral resolution as this allows for a better discrimination against telluric interferences In order to be able to realize these high sensitivity values in practice however possible sources of fringing e g interference filters have had to be avoided and the requirement on the grating reproducibility is set to 0 05 pixel in order to avoid limitations by flat field artifacts If the wavelength reproducibility cannot be achieved blind it will be obtained by active spectrum control using sky lines as the reference This means that the nominal velocity accuracy corresponds to this or 70m s Even higher accuracy is possible using the absorption gas cells although the actual gain depends strongly on the actual line density of the selected gas in the wavelength region of interest First light image of the sky is shown in Fig 13 The OH doubled at 1708 6nm is resolved at the resolution of CRIRES This doubled still appears as a single line in the high resolution mode of ISAAC demonstrating the resolving power of CRIRES In dispersion direction the FWHM is 2 8pixels 5 1 AO Guide Stars In CRIRES the wavefront sensing occurs with the optical light lt 1jm The distance of the AO guide star 18
74. p are possible between the science templates offsets of more than typically 1 arcmin will imply the re acquisition of the telescope guide star i e produce a large overhead unless you specify smartly your telescope guide star in the template 37 10 1 Acquisition Templates The purpose of an acquisition template is to point the telescope preset to a given celestial position Four different CRIRES acquisition tasks are distinguished 1 science target used for AO and SV This should be the default option 2 AO and SV adjusted on bright compact object outside the slit and where science target e g nebulosity position is given as offsets from bright compact object 3 no AO calibration star is used and the slit is wide open gt 0 5 1 4 no AO on extended science object without bright compact object in the field The slit is at the moment mechanically frozen to a fixed slit width of 0 2 so that it cannot be moved as foreseen in task 3 above and is therefore omitted All acquisition tasks required for CRIRES are implemented using a single interface which is driven by pop up windows Starting from the usual BOB interface which is shown in Fig 18 there are four additional interactive windows as for the four main steps during the acquisition tasks For each step the pop up window gives a short description followed by a parameter section with default parameters They can be overwritten by the IOP After parameters ar
75. pixels 5 6 Limiting magnitudes Limiting magnitudes S N 10 per spectral pixel for a point source in 1h on source integration are Band Limiting Magnitudes continuum For more detailed exposure time calculation we encourage to use the exposure time calculator 5 7 The Exposure Time Calculator The CRIRES exposure time calculator can be found at http www eso org observing etc it returns a good estimation of the on source integration time necessarv to achieve a given S N as a function of atmospheric conditions A few notes on input parameters e the parameters to be provided for the input target are standard The input magnitude can be specified for a point source for an extended source in which case we compute an integration over 26 the surface defined by the input diameter or as surface brightness in which case we compute values per square arcseconds e if an AO guide star is used do not forget to tick the box AO under instrument set up and provide the values for AO guide star distance its R mag and B R color The two latter can be obtained from many of the online star catalogs e g GSC Il USNO UCAC and are used to compute how much photons will be available to the wavefront sensor whose response curve ranges from 450nm to 900nm and peaks around 650nm e Results can be given as exposure time to achieve a given S N or as S N achieved in a given exposure time In both cases you are requested t
76. r V magnitude needs to be determined according to AO requirements 39 INS WLEN ID defines the optical configuration of the instrument and set up DIT and the detector read out mode INS WLEN ID is given by three parameters order number scanning number and mode Higher order numbers are at short wavelengths where it is not necessary to scan the order to get its full wavelength range However at larger wavelengths respectively small order numbers the detector cannot cover the full wavelength range of the order In this case and to be able to measure the complete order one needs to apply a scanning strategy For the highest wavelengths up to 5 scans are necessary They are labeled by an interger number which is lt 2 Finally INS WLEN ID includes the mode which can be l for interlaced or n for normal In normal mode there are gaps in spectral regions which coincide with physical gaps between the four individual detectors To fill those gaps the inerlaced mode is applied One example of INS WLEN ID is 59 0 n The observer is restricted to enter values of INS WLEN ID as described in Appendix X DIT and NDIT are Detector Integration Time and the number of DITs to be integrated before writing the data to the disk NDIT is a user defined parameter and controls the total nitegration time but DIT is not DIT is specified by the optical configuration which is given by INS WLEN ID RA DEC Equinox and Position angle on the sky define the respective
77. ristics are summarized in the following Table and Figures RIR M i E PTF of CRIRES science detector 2 goin 7 664 0 082 e ADU Signel e Voroionce ADU 2 dork current 3 174E 001 3 5 003 e s La re L a a D A 0 5 0x10 1 0x10 1 5x10 2 0x10 2 5x10 o 1000 2000 3000 4000 5000 6000 Integrotion time s Signo ADU Figure 14 Dark current left and conversion gain right of one of the four science detectors In Fig 14 dark current and conversion gain of detector 2 is shown The dark current is estimated from the slope of the signal in ADU or e as a function of integration time s for the linear region Dark current of the four detectors 1 2 3 and 4 is 0 0527 0 0317 0 0369 and 0 0344 Je s respectively The conversion gain is measured by taking flat fields at different flux levels One estimates the noise in a good cosmetically clean part of the individual detector arrays and plots the variance versus mean signal The inverse slope is the conversion gain Je ADUJ The conversion gain of the four detectors 1 2 3 and 4 is 7 737 7 664 7 689 and 8 077 e ADU respectively Saturation levels for the science detector 1 and 2 is 16000ADU corresponding to a storage capacity of 120000e The cosmetic performance of the detectors is improving by lowering the detector temperatures On the other hand as readout noise is lower for higher detector operating temperatures one needs to search for th
78. ror depends on the position of the guiding star in the field In order to keep the pupil image obtained when the membrane mirror is flat centered on the lenslet array the membrane mirror is mounted on a 2 axis gimbal which is co ordinated with the field selector For each x y positions of the field selector the gimbal mount is moved so that the light is reflected to the same focus A diaphragm in front of the membrane enables the field to be adjusted to the observing conditions seeing and guiding reference size The assembly of the gimbal mount is shown in Fig 6 The wavefront sensor box consists of 4 mirrors which provide parallel beam to image the pupil on the lenslet array First the beam is collimated by a spherical mirror It is then folded by a flat mirror and injected in the beam expander which adapts its diameter to the lenslet array 14mm The optical path of the wavefront sensor box is shown in Fig 7 Figure 7 The optical path of the wavefront sensor box The lenslet array intercepts the beam and divides the flux in 60 sub aperture Each sub pupil is imaged on a fiber with a 100 um core diameter When the membrane mirror vibrates the pupil image is projected on both sides of the lenslet array plane The normalized difference between the intra and extra pupil flux collected by each sub aperture is proportional to the local curvature of th
79. rovides a 240 mechanical stroke i e 3 6 on the sky with a 100Hz 3dB internal closed loop bandwidth The assembly of the DM and tip tilt mount is shown in Fig 6 3 2 2 The Wavefront Sensor The following functions are sequentially implemented in the wavefront analyzer e Extraction of the reference star beam field selector e Projection of the reference star image on the membrane mirror imaging lens Scan of the intra and extra pupil regions by modulation of the membrane mirror curvature Creation of a pupil image centered on the lenslet array e Reduction of the flux for bright reference stars within the linear range of the APDs by means of neutral density filters 12 e Re imaging of the 60 sub pupils on the 60 fiber cores by the lenslet array unit e Injection of the collected beams in the 60 APDs The scanning lens of the field selector is mounted on an XYZ table the XY axes enable the guiding star to be selected in the 50 x 50 field of view while the Z stage compensates for the VLT field curvature The position of the field selector defines the reference for the pointing The imaging lens is creating an image of the guiding star on the membrane mirror which is mounted to an acoustic cavity A voice coil is mounted to the other end of the cavity and driven at 2 1kHz by the APD counter module to force an oscillation of the focus mode of the membrane mirror The incidence angle of the beam on the membrane mir
80. t 40km resolution lo volcanic activity SO Pluto Charon Triton CO CH search Comets H20 abundance temperatures velocities e Stars stellar evolution and nucleosynthesis CNO abundance stellar mass stellar radii stellar winds and mass loss atmospheric structure and oscillations magnetic field structure e Star formation and ISM accretion and outflows ISM chemistry and cloud structures Hi H20 CHa e Extragalactic astronomy AGN velocity structure of the broad and narrow line region Fell H5 lines in low extinction regions H recombination fine structure lines 1 3 Structure and scope of the User Manual The CRIRES user manual is structured as follows e A technical description of CRIRES and its adaptive optics system AO is summarized in Sect 2 and Sect 3 e Observing modes offered for this period and performance of the instrument are given in Part Il e A guide through phase and phase Il observation preparation is given in Sect 6 An overview on how to observe with CRIRES at the VLT can be found in Sect 7 e Acquisition observing and calibration templates are explained in Sect 10 CRIRES User Manual VLT MAN ESO 14500 3486 3 This is the first issue of the CRIRES User Manual It provides information required for the proposal preparation phase l The manual will be up dated for the proposal phase Il when more compre hensive information is avail
81. t for each setting one can expect to have sufficient sky lines Therefore in general the absolute wavelength calibration is not better than given by the present instrument model see item before It is a goal of future commissioning runs to improve the absolute wavelength calibration e The field of view of the spectrograph is slit width x50 The nominal slit width is 0 4arcsec giving a resolving power of about 50 000 Using the smallest slit width of 0 2 and hence higher spectral resolving power is not recommended for the moment because of large slit losses of as much as a factor 3 compared to the nominal slit width e Caused by some bad detector characteristics we recommend to apply as observing strategy nodding of one or more AB cycles Starring observation on one nodding position A is possible but shall be avoided because of detector glow effects which is strong for bright targets At the price of vignetting the resolving power can be ramped up to more than 10 Such an operation is not excluded but not part of the baseline considerations for instrument calibration and operation 22 5 3 Detector characteristics CRIRES is equipped with four 1024 x 1024 pixel InSb detector arrays in the focal plane of the spectrograph Observers shall use the ETC to optimize DIT NDIT values All other detector settings voltages best read out scheme etc are calculated for each setting automatically by the system Some detector characte
82. t viewer sensor echelle gratin _ 3 mirror TMA 8 E collimator camera Figure 1 Layout of the CRIRES optical design 2 2 Mechanics CRIRES is stationary at Nasmyth A focus of VLT Antu UT1 The instrument is mounted in a vessel of 3m diameter and 1m height Including support structure the total weight of the instrument is 6 2t The warm part of the instrument is 2t and the cold parts 4 2t respectively The optics inside the cryo vessel is cooled to 65K and the detectors to 25K A main design feature of CRIRES are its cryogenic mechanisms which are required for scanning the prism 1 and echelle grating 67 the two slits plus the slit viewer filter and Wollaston wheels The scanning functions are driven by cryogenic stepper motors baseline Phytron and high precision screws and encoders The main elements are the cryogenically cooled spectrograph in its vacuum vessel the table mounted un cooled pre optics calibration unit field de rotator adaptive optics system between it and the telescope Nasmyth adapter rotator and the electronics racks The instrument is mounted stationary on the platform primarily to ensure achievement of the high wavelength stability requirements by minimizing flexure and temperature variations The vacuum vessel is made of austenitic stainless steel with a high internal reflectivity achieved by manual polishing followed by electro polishing Attached to it are two Leybold closed cycle coolers the i
83. uality at the telescope preset is obtained 34 Part Ill CRIRES data format 8 The CRIRES data reduction cookbook The CRIRES pipeline has been will be developed by ESO DMD and uses the ESO CPL library The main observation templates are supported by the pipeline reductions Raw images are recom bined spectra extracted and calibrated in wavelength Sensitivity estimates based on standard star observations are provided More information will be found at http www eso org observing dfo qc once the pipeline will be readv for distribution Part IV Reference Material 9 CRIRES scientific calibration The calibration plan defines the default calibrations obtained and archived for you by the Paranal Science Operations This is what you can rely on without asking for any special calibrations CRIRES science calibrations plan includes the following measurements AO calibration tasks are not mentioned Calibration Purpose CRIRES spc cal Darks CRIRES pc cal Detec Trans CRIRES spc cal Flats CRIRES spc cal Emis CRIRES spc cal Abs CRIRES spc cal Dist CRIRES spc cal StandardStar CRIRES spc cal scale CRIRES spec cal prism Darks and bad pixel map instrumental background RON gain bad pixel Pixel to pixel gain variation flats Pixel to wavelength relation using emission lines Pixel to wavelength relation using absorption lines Fit parameters for distortion map Photometric conversion sensitivities Measur

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