Recovery and meridian flips


I have a major problem with SGP. I have captured so much unattended data in the last few months, that I have not got the time to process it :laughing:. That being said, I got caught out last night and it prompted an idea:

I had a band of cloud come over around the time of the meridian flip. I only slew (not center) and I discovered this morning that my system had gone to bed. It occurred that if you have cloud, one cannot center after a flip, but there is nothing stopping the slew-only command, which would allow the recovery to continue to try and work on the other side of the meridian?

Would that be safe and reasonable?


Sure. It just depends on if your slew is accurate enough to start imaging.


within 4" RMS :slight_smile:


Just like buzz, I have encountered many similar problems: Meridian failed to flip, slew/center solve failed, recovery failed, and I use my SGPro very carefully, pray it could run stably.

If the existing features could run stably, SGPro would be a very good automatic astro photography software!

I have just installed v2.5.2.1, and hope it can solve these problems.


sshyang - I think you missunderstand me. I have extremely good reliability with SGP (V2.5.1.17), so much so that I have too much data to process! I have no issues with meridian flip and when I’m using slew/center with the PMX it works perfectly. In my other post, I was prematurely trying out the new beta program with its sync offset feature.

At the moment I have a TPoint model - so I do not use ‘center’ Currently the recovery process aborts at the meridian. It is clearly documented that it does. Obviously, if the system is in recovery mode, it is normally the case that there is cloud cover and so any centering process would not work, My suggestion was that, in the case of recovery mode, if it gets to the meridian, rather than aborting the sequence, it executes the meridian flip but does not do any centering. (In fact if centering had been enabled, it could be executed just before the sequence resumed.)

The existing features are stable. There are a few minor concerns, but what software is perfect? The software is, however, part of a complex system, which includes the user, which is not under their control !



It’s almost always your settings that are causing it to fail. My best advice is to try different times. Most mounts require you to be in a ‘window’ around the meridian or it won’t flip. These are set by your GOTO limits usually. You can test meridian flips during the day. In addition, plate solves around meridian flips often fail if you don’t have an adequate delay for settling the mount after a flip. If your stars trail, you can’t expect the plate solve to work. Recovery mode won’t save you because it is commanding a slew, which requires settling… you can see how that can snow ball.

Without logs and understanding your particular setup, it is very difficult to help you.


Oh, I’m sorry, I missunderstand buzz.
In, I reported the bugs, and Ken suggested that I could upgrade the SGPro to v2.5.2.
A few days ago, I upgraded my software, and improved configuration of the PHD, hope these changes can take the successful photography. There are many users with the same problems I have encountered in China, if I solve the problems, I will communicate with them.
Oh, Buzz, envy you can shoot a lot of photos. :stuck_out_tongue_winking_eye:
Apologize for my misunderstanding again, my English needs to be improved.



Meridian flips failed again, please help me
Thank you very much!




It’s hard to tell why, but the call to stop and restart your guider failed. I think it is a timing issue related to using the onboard SBIG guide chip through PHD2. I have made the fragile parts of this method a bit more robust by adding retry attempts when this situation is encountered.

Meridian flips failed again, please help me

Ken, thank you very much. :slight_smile:

I suspect this problem may be caused by a combination of factors:


Yes, set the Ioptron mount to a larger number of degrees than what you set in SGP. You want SGP to initiate the flip not Ioptron hand controller.


Thank you~!