Solar Scintillation Monitor User manual
Contents
1. AiryLab Solar Scintillation Monitor User manual Special thanks to M Edward Joseph Seykora for his authorization to use his initial design and his kind wish of success and both Jean Pierre Brahic and Christian Viladrich for their extensive testing SSM 2015 by Airylab Reproduction restricted Quick start Presentation Thank you for buying Airylab s Solar Scintillation Monitor SSM This device will allow you to determine instantaneously the seeing value in ArcSec at your specific location by daylight for solar observation and imaging The SSM has been designed for three main applications Help you to find the best observation site for solar visual observation and imaging The small handheld form factor makes it very easy to bring to potential locations for a quick survey Determine the best seeing time for your observation location Used with its data acquisition software you may collect data over the day to see the general seeing evolution over time Directly command image acquisition when used with Genika Astro In that case Genika Astro connects to the SSM directly and trigs acquisition from the camera when the seeing goes below a predefined value For more information about this topic please refer to Genika Astro user manual Operating the SSM SSM location Be very careful about the location of the SSM during measurement It should always be located near the telescope entrance pupil or its projected location2. If positioned too far from the telescope the readings reflect only the seeing at the SSM actual position rather at the telescope aperture Both may be very different depending on the environment Example when the SSM is placed upon a metallic or plastic table top the seeing is deeply affected by the very local turbulence caused by the table surface heating When connected to a PC you can use an USB cable up to 5m to optimize the SSM position near the telescope entrance It is also possible to remove the photodiode from the SSM and connect it through a shielded extension cable Kindly pull up the photodetector it is connected to a low insertion force connector The cable shield shouldn t be in electrical contact with the telescope or the mount The shield must be connected only to the ground pin at the SSM end not the photodiode the ground is on the pin on the side of the small metallic rectangle on the photodiode Use a two wires connector shield foil For short distances you may use an unshielded double conductor cable Use the JP1 on the PCB to connect the photodiode It is accessible through the photodiode hole Power supply The SSM standalone can be powered from its jack plug It accepts 6 to 12V input Note that if powered from a car battery the SSM should not be used for an extended period of time as the battery delivers about 13 8V unloaded and the module may overheat You may use a rechargeable battery pack or a LIPO battery as
3. 730 me be LB P7 pwa 08 00 52 on 1009 091911 2821 0937 1 The SSM create a new COM port on your PC If you don t have any other Arduino based system you may try the autodetect option You may also manually select the COM port Then press the connect button After a few moments the readings from the SSM are display on the charts The upper right chart displays the input level evolution The lower large chart shows the instant seeing value evolution Three scales and three chart type are available from the button above the chart The upper center chart resumes the long term evolution from the average value on a full minute You can log the seeing values in a text file by checking the result in log file checkbox The file is automatically created in the folder that may be selected with the button Select directory A new file is created if you uncheck recheck this box You may also reset the main chart at anytime this does not stop the data logging in the file General solar observation guidelines As a general guideline your solar telescope should be used at a position that minimizes the first meters turbulence sources Avoid concret choose if possible grass covered ground Water surrounded locations shows minimal low layers turbulence Higher is better If you have an elevated terrace it could be a good location Mountain site are usually better but avoid mid slope positions as they present ascending ai
4. iography JACQUES M BECKERS 2009 USING THE SCINTILLATION OF EXTENDED OBJECTS TO PROBE THE LOWER ATMOSPHERE Optical Turbulence pp 23 25 Solar Scintillation and the Monitoring Of Solar Seeing E J Seykora Solar Physics 145 389 397 1993 Using Scintillation Measurements to Achieve High Spatial Resolution in Photometric Solar Observations R Coulter J R Kuhn and T Rimmele Solar Physics 163 7 19 1996 SSM 2015 by Airylab Reproduction restricted
5. lue Seeing varies on a high frequency that explains de constant reading fluctuations For short run high speed imaging the fast refresh rate of the SSM allows to trig image acquisition at the proper time when coupled with Genika Astro Using the SSM with its Windows application Installation The SSM uses an Arduino module as a main CPU The drivers are provided with the SSM application in the drivers folder Depending on your operating system x86 or x64 execute the dpinst amd64 exe Windows 64 bits or the dpinst x86 exe Windows 32 bits emeen EP EUF WEEE Ee Ei eS Ce di FTOI USB Drivers 26 11 2014 14 31 Dossier de fichiers arduino cat 16 09 2014 15 46 Catalogue de s cu 10 Ko 4 arduino inf 16 09 2014 15 46 Informations de c T Ko Z dpinst amd 4 exe 16 09 2014 15 46 Application 1024 Ko ZE dpinst x86 exe 16 09 2014 15 46 Application 901 Ko 4 drivers_Arduino zip 04 03 2015 09 49 Dossier compress 1 883 Ko 4 Old_Arduino_Drivers zip 16 09 2014 15 46 Dossier compress 14 Ko H README tet 16 09 2014 15 46 Document texte 1 Ko Then install the SSM software You may connect the SSM to the USB port and launch the SSM software SSM 2015 by Airylab Reproduction restricted son ane pana ppg me ne 1 mn average Input level keep gt 0 5 and lt 1 Fant r log te 3 ns une wee Carre 5 T Soio D D4 haaat rach Aso E Gaai lz rod Input 0 800 J e Mna cae app 375 CE 5 1 3837 69 01 57 09125 092756 34 Seeing 1
6. r currents Avoid concrete or stone walls close to the telescope The seeing also varies deeply during the day Except on specific location such as high mountains top the best seeing is usually during the morning and second part of the afternoon SSM 2015 by Airylab Reproduction restricted Understanding what the SSM measures Scintillation from an extended object such as the Moon or the Sun is mainly caused by low layers up as shown below This is the exact opposite situation when considering stellar object For those scintillation is rather due to higher atmospheric layers at the jetstream level SCINTILLATION INDEX ar FOR VARIOUS OBJECTS FOR 1 ARCSEC SEEING LAYER AT HEIGHT H STARS URANUS MARS JUPITER SCINTILLATION INDEX SUN amp MOON HEIGHT H meters NOTE FULL DRAWN LINES ARE FOR OUTER SCALE L INFINITE CIRCLES ARE FOR OUTER SCALE L 20 METERS From USING THE SCINTILLATION OF EXTENDED OBJECTS TO PROBE THE LOWER ATMOSPHERE JACQUES M BECKERS For the sun the scintillation level is about 7E 7 of the total light in the first ten meters 1E 7 at 100m and 5E 8 at 10km On the other hand according to the Hufnagel valley model that is widely accepted atmospheric turbulence originates mostly from both the jet streams at the tropopause altitude 7 12km and the lower layers below 5 km E lt O 40 distant rarefied tropopause E high velocity turbulence 2 G 5 proximate dense bo
7. the power consumption is below 100mA You may also power the SSM through its USB port when connected to a PC or to a generic USB power supply SSM 2015 by Airylab Reproduction restricted Readings The internal LCD screen gives two values updated twice per second Input The input gives the level incoming light on an arbitrary scale The photodiode sensor has an effective operating angle of 180 Depending on the SSM orientation and sun elevation this value would change along time The input value should be kept between 0 5 and 1 at all time If the value goes below 0 5 the SSM stops to calculate the seeing value That can be the case when clouds pass by If the value goes over 1 seeing values are calculated but with less accuracy as the input amplifier chain may clip some data You may adjust the input back to less than 1 either changing the SSM orientation or using the internal rotating trimmer located next to the photosensor with a small flat screwdriver Note that it is possible to set the trimmer in a position that allows to run a full sun cycle with input between 0 5 and 1 Seeing This value gives the seeing in ArcSec The value is calculated from the sun light high frequency scintillation Very small variations of the light reflect the actual low altitude turbulence that is preponderant during daylight Seykora 1993 Beckers 1993 2009 The SSM measures the incoming light 1400 times twice per second and calculate the seeing va
8. undary layer low velocity turbulence 10718 10 17 10 16 10 79 turbulence structure C The Hufnagel Valley model Hufnagel Valley 1979 SSM 2015 by Airylab Reproduction restricted That is even truer when considering daytime turbulence If you consider the integral of the turbulence on both graphs below you can see that most of it in due to the first kilometer by day Observatory height 2630 meters 001 0 01 0 1 10 10 0 100 001 001 01 10 10 0 100 Height km Dotted line is daytime Beckers 1993 105 min al 4 10 km Dotted line is daytime Roddier 1981 Scintillation analysis with a dynamic better than 10 as used in the SSM allows to measure contribution to the turbulence from the lower layers that are the main contributor to daytime seeing Professional observatories are using photodetectors linear arrays SHABAR systems that can spread out the contribution to the turbulence of the different layers of the atmosphere The SSM is a simplified low cost version for amateur solar astronomers using a single photodiode Its dynamic is able to show turbulence of the first couple of kilometers at least It is important to remember that this measurement is less sensitive to higher layers induced turbulence i e jetstrams With the same seeing readings on two different days the actual turbulence may differ due to different jetstreams speeds SSM 2015 by Airylab Reproduction restricted Shortened bibl
Download Pdf Manuals
Related Search