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Observing ISS (and other satellites)
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Dear all,
I create a specific thread for observing satelittes by copying / pasting? some exchange that was done in /g/ServoCAT/topic/autocal_cable_length/106277132? My initial message : After having updated servocat to version 7 and ArgoNavis to version 3.04. I have for the first time succesfully? observed ISS with AN/servocat . Ssssooooo happy !
It was done with my 36" F3.5, with Ethos 21 => magnification x173,FOV 34' I have made some optimisation of the gear ratio but the follow up of ISS is average : I had to push the guide fast right button in continue when ISS was higher speed.
My answer to Gary :I think my gear ratios could be impoved (see above message) and Gary provided support on this. Gary answer : TIME is the very most important criterion. It has to be precise to the second. Alignment I believe is the next critical item. Gary Kopff from WCI can respond to this... the track of any object is going to be an approximate one with the error being directly related to issues of alignment. Mount error - i.e. the mount (the scope) is not made to a very high precision (in most ServoCAT systems it is a WOODEN telescope meant for visual use). So issues with bearing placement side to side forward/backward up/dwn... will come into play.? Hold on - I just re-read your note - you didn't REALLY 'see' the ISS ... in a 36" DOB!? Is there is a translation issue there? When I was working on the ServoCAT side of designing this - with my 12" out in the backyard - I knew that doing any type of fast-ish tracking for Earth orbit objects would be limited by the size of the scope and ESPECIALLY if there is a ladder involved... I can't imagine trying to follow with a ladder. I know I did a bunch of booster rocket tracking - and it was moving pretty darn fast. (and it is SO COOL to see this happening - one of the first times this was working I was looking and thought - "its not working, the stars are flying by in the view" ... then I looked again and BINGO - the object I was looking for, however, was DEAD CENTER STATIONARY in the filed. It was a weird sensation). Hi gary,
No translation issue, it is with a 36" dob. Enclosed a picture.
Yes, looking the star "flying" was amazing? ! and you see ISS enlarging little by little, see the solar panels as it comes closer then reducing size. All this was great.
For accurate time, I did the calibration of the internal clock of AN as indicated in manual using (NTP protocol), so I think it's OK
Regarding the ladder issue : in fact my 36" is e Fullum folded scope so it don't need tall ladder. I would say I don't use anything until maybe 40-50¡ã . At zenith 2 steps is enough for me (I'm not tall 1.73), 3 steps for small people, so I have only a 3 step ladder. When I watched ISS it was not a problem in first low alt passage. More an issue at 2nd?passage nearby zenith but the ladder was manageable. The main problem I have is certainly the pointing precision not enough on the 36". The pointing precision is not optimal and objects are classically not in the fov. 1 or 2¡ã away.?
Since few observation, I start to use more and more the wonderful TPAS of AN. But so far I limited to maximum 30 stars => the parameters are not accurate enough yet, and I hope I don't have a non persistent error.
This Is 1 of my goal in the next month or let's say automn goal to improve TPAS.
When I followed ISS, I had already calculate 2 parameters of TPAS so the pointing was better than usual but anyway, the ISS was just outside of fov. I could easily recentered it but it means the pointing was still not perfect.
I had to continuously push the az "CW" button in guide fast mode to keep ISS in the fov. The azimuth following was nearly perfect. |
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