John and others,

I am having a problem guiding with my SBIG Remote Guide Head and MOAG-A running under CCDAP and CCDSoft. I have never seen this issue before when running with my internal STL guide chip. Also, I am not able to repeat this problem when I isolate and test with CCDSoft alone. I have seen this across several nights and have re-initialized several times with the same ending outcome with second or third targets on my runs. You will note in the attached log file that I attempted to image three different targets. All targets started on the west side of the meridian. The first target guided as expected. However on the next two targets what appears to me is that the guider X axis (or something that looks very similar in symptoms) gets reversed and guide errors increase in magnitude as the guide star is pushed away from the center of the autoguide window. No other variables that I can see were introduced after the first target was guided successfully other than slewing to the next target and rotating. The guide star ADU is obvious in the CCDAP log as actually having the guide star on the guide chip, so that is not the issue.

I was able to observe this same problem in real-time at the beginining of one of my runs this week. I watched the start of a new CCDAP run and noticed that the guiding was failing. I flipped over to CCDSoft, guided there and it only worked correctly when I reversed the X axis. I went back to CCDAP and tried again and watched the guide star get pushed out of the window under CCDAP controlled CCDSoft as well. I re-intialized in CCDAP and changed nothing else, ran again, and that first target guided succesfully this time. Under that same run though, the second of two targets appeared to be doing the same thing when looking at the log later with the guide errors increasing in that same manner. I would be testing and diagnosing this a bit more before coming to the group if all I had was the logs to go by, but having seen this at the start of one of my runs and having watched the problem in real-time, I feel like it is something that is a real problem in the calibration/initialization or something else I cannot easily diagnose. Also, having this happen most of the time only after a first target succesfully guides is even harder to explain.

I have not been able to recreate this under CCDSoft alone, having calibrated there and tested guiding in isolation with success. Perhaps this is not a CCDAP-specific issue, but I cannot recreate it outside of CCDAP...

Any help would be appreciated in trying to solve this. I plan to use the RGH/MOAG-A combo much more for narrowband imaging and with my AO-L to increase my guide star selection guiding in front of my filters.

Also using this with the Sky6 and a Paramount.

Thanks,
David Plesko

ccdap20080314_213258.log (75 KB, 78 downloads) Example Log File

See the Equipment Topic under Guider. Have you tried SelfGuidedR? That is generally necessary when an OAG is used.

John--Thanks very much as always. I knew there was something unique about the OAG and CCDAP but could not recall what it was or where to look. Of course I did not go back and look at the help as I thought I was now an "expert" on CCDAP and like many users, read all the help when I first started using it and then forgot it existed. My OAG FOVI is below the imaging chip, so I suspect this will fix my problem. Thanks again and good luck on the next version. I am quite excited to see what you turn out. I have a hard time believing it could be better than what you have created in V3, so it must be pretty great!

Thanks,
David