I used CCDAP at the Deep South Regional Star Gaze last week. We had 5 clear nights in a row, and the scope was collecting images of multiple targets from dusk to dawn. Thanks to CCDAP, I was able to visit and observe most of those nights and get some sleep for a change. Great software. The few tweaks I had to make were easy with the logs of each run.

I had a problem with plate solves on one object. The horsehead would not plate solve. I have read that nebula can cause problems. My threshold setting under CCDSoft is at 1.25. I think I had it as high 10 a year ago but moved it down upon reading some threads on the subject.

Does a higher threshold setting of 10 make it more likely that I will get a plate solve in all situations at the cost of a less accurate solution than at 1.25? If that is the case, since I am not using the plate solve for astrometric work, is the less accurate plate solve "close enough to get the guide star back on the chip?

Even with the failed plate solutions, the ME got the star back on the chip. My precision slew corrections when the plate solve works, which is most of the time are 1 to 3 arc minutes, but can go as high as 8 arc minutes. My sbig 402 guide chip is about 4.6 by 7.6 arc minutes, so sometimes not getting the slew correction may cause a problem.

Hi Kirk,

Glad things are working well mostly.

Generally increasing the detection threshold in the presence of nebulae to 2 - 3 should resolve the issue. Look at your log to see the file names of the failed sync images. They are saved by default. Then bring those files into CCDSoft and try plate solving with different detection thresholds. A setting of 10 is generally too high to get plate solves. Look for a range of 1.25 to 5 to experiment with.