Unexpected Recovery Mode after meridian flip

I had an incident last night where SGP went into recovery mode when resuming guiding after a meridian flip. According to the SGP log, SGP thought that PHD2 had lost the guide star:

[5/14/2015 12:53:35 AM] [DEBUG] [Sequence Thread] Recovering the sequence (and the auto guider lost the guide star)

but the PHD2 logs shows no indication of any loss of the guide star at that time, but they do show show phd2 sucessfully locating a star and guiding.

Here are the logs: http://adgsoftware.com/misc/sgp_2015-05-13.zip


Actually, your PHD logs seem to have quite a few star lost messages… most notably just before the flip.

00:51:25.552 00.000 5904 Status Line 0: Star lost - low SNR
00:51:25.552 00.000 5904 UpdateImageDisplay: Size=(752,559) min=930, max=1004, FiltMin=944, FiltMax=987
00:51:25.588 00.036 5904 UpdateGuideState exits: Star lost - low SNR

Not sure why that happened to your guider, but SGPro (per a conversation with you) considers a star lost if we receive a star lost message with a distance of greater than 100px. Once this happen, the recovery was just waiting to happen (unnecessarily). The next time SGPro could attempt to recover (after the flip), it did. I think, that we need to make sure the star lost indicator is set to (and stays) clear during any auto centering movement (this is essentially a sort of recovery anyhow).


If you were using SX Lodestar or Superstar, are you using latest SX driver? If so, I and several others have found latest SX driver a little bit unstable (timeout or disconnect) and reverted back to previous version which is still available from SX web site and the problem seems to be eliminated. Your case may not be a disconnect issue but could be caused by latest SX driver.

Or is it possible that clouds came by when guide star was lost? Happened to me a few times.


Hi Ken,

Thanks for looking at at. So I guess you are saying it was the star lost events before the meridian flip that triggered the recovery. It does seem a little odd to me that the successful flip and guiding after the flip were affected by what happened earlier, but I guess I can live with that :smile: Perhaps an opportunity for some improvement here, but certainly not a big deal in the scheme of things.


Hi Peter,

Thanks for the ideas. I am using a Lodestar (x2) but it has been quite stable–no disconnects ever in the time I have had it. I live in the Northeast where passing clouds can always be a problem so I’m certain that was the root cause here.


Well, no, that’s my point. If you enter any centering action we need to clear the recovery flag. The centering action is a recovery in and of itself. So the fix will be to do a recovery OR any centering action to get the sequence back on track.

well that’s even better, thanks!