[Edit: Updated thread title to reflect new info below]
When the SGP log notes that “guider reports that it is not guiding,” does that just mean that PHD2 had lost the star at the instant that it was polled by SGP? If so, what happens then? I was guessing that PHD2 keeps getting polled, and eventually SGP assumes guiding can’t be recovered, and aborts, but testing tonight suggests that SGP aborts almost immediately. Is that correct?
I had a marginal guide star at one point this morning - mag 11.5, best I could get on a target in Coma Berenices with my OAG - so it was being lost occasionally by PHD2, but was always recovered. If anyone wants to look, the SGP log and the PHD2 guiding and debug logs are zipped up here. The sequence was aborted around 4:07 am.
Edit: I checked the SGP and PHD2 debug logs in more detail, and found something interesting. At 04:07:25, SGP sends a dither request. At 04:07:32.037, PHD2 logs that it lost the star. At 04:07:32 SGP sends a status request, and notes that it got a 4 (not guiding) back. It immediately sends another status request (in fact, in the PHD2 debug log, these status requests show as being only 1 millisecond apart). Of course PHD2 hasn’t recovered the star yet, and reports another 4 back. SGP then aborts the sequence. Only 1 millisecond after the second status request, PHD2 recovers the guide star. 35 milliseconds later, SGP sends a third status request (I’m not sure why), and gets a 3 (guiding) back. But the sequence is already aborted. I saw very similar behavior in a guiding run early tonight as well.
Is this normal behavior, to give PHD2 effectively only one chance? I had understood that SGP waited for a bit to see if the star was recovered, and only then gave up and aborted.