I’m having a persist and strange mount tracking problem that I and others have been unable to resolve, so I’m seeking a bit of advice here. The mount is an iOptron CEM120EC in a remote location.
The problem is that at some point prior to the meridian the mount simply stops tracking. At that point PHD loses the guide star and SGP goes into recovery mode. The stars are streaking across the PHD2 screen. This has happened each of the last 4 nights, but it happens about 15-20min sooner each night. In other words, on night 1 it happened at 10:45pm, night 2 10:25pm, night 3 10:05pm, night 4 9:45pm. (On night 1 the object would have crossed the meridian at 10:55pm)
I have confirmed with others that the meridian limits are set correctly in the iOptron Commander driver, and I have not set any horizon limits in SGP.
As a daytime test, using only Commander and no other software running, I slewed the mount to about an hour before the meridian and close to the same position as the imaging target and enabled tracking. The meridian behavior in Commander was set to track to the meridian and automatically flip. The mount tracked correctly and flipped correctly. I repeated this test but had the mount track 2deg past the meridian before flipping, which it did again correctly.
That tells me the mount is operating correctly and that “something” else is telling the mount to stop tracking. The only software running is Commander, PHD2, SGP and the Pegasus UPB software.
I can’t see anything in the SGP log file (HERE) but I would appreciate if someone more proficient at reading these logs would take a look. The issue happens at 21:49:23.
Had a look at the logs but don’t see anything there.
SGP + the mount seem to think that the meridian limits are still set correctly and that you were over 12 degrees away from needing to perform a flip:
[01/25/22 21:49:19.935][DEBUG][Sequence Thread][SQ;] Checking if Meridian Flip is needed
[01/25/22 21:49:19.935][DEBUG][Sequence Thread][SQ;] Telescope is on the West side of the mount
[01/25/22 21:49:19.938][DEBUG][Sequence Thread][SQ;] Meridian Flip not needed, Hour Angle < Degrees Past To Flip: -12.8942583397701 < 0
Are you sure that at the moment the issue occurs the meridian settings in Commander are still set as expected? i.e. “something” hasn’t caused them to switch to “Stop at designated position” instead of “Flip at designated position”?
Yes, I’m sure about the Commander settings. I had the mount set to “Stop at designated position” and set it at 7deg past the meridian. Those settings didn’t change and that really is just a failsafe in case SGP doesn’t call for the mount to flip before hand.
Last night I changed the degrees past meridian to 2deg instead of 7, because that’s what I used for my daytime test, but that made no difference. The mount stopped tracking well before the meridian as you noted.
A couple of gotchas - is the location and time data correct?
Does the mount have an encoder? How does it know where it is pointing… is there a home sensor or something.
Are you connecting via a planetarium (like TSX), just trying to see if something else is getting in the way.
Lastly, is the mount physically stalling - does it says it is not tracking, or is just not moving!?
Steve,
I have only been using this mount for about a month and it took me a couple of nights to understand what was happening. To the best of my knowledge nothing has changed since I started using it. The mount firmware and Commander are the latest version, still using ASCOM 6.5 sp1. After the first couple of nights this happened I did update SGP from 4.0.0.683(?) to 4.0.0.700 but there was no change in behavior. I even created a new sequence from scratch last night, NOT using the equipment profile I had set up, but the mount bahavior and SGP behavior were exactly the same.
joel
Buzz,
The mount has an RA encoder. The driver allows the mount to automatically find the “zero” position (CWD, pointed at NCP), and also an automatic encoder calibration. I’ve done both of those. The mount correctly goes to the zero position and parks at the spot I have chosen.
I am not using a planetarium at all. The only software running is SGP, iOptron Commander (ASCOM driver), PHD2 and the Pegasus powerbox software.
The mount simply stops moving, but Commander reports that it is still tracking. When this happens I watch the stars streak/drift across the PHD2 looping screen.
joel
Correct, the mount tracks properly and handles the meridian properly when it’s just Commander in the mix. I’m not exactly sure how I would eliminate one of SGP or PHD and still be able to run the sequence, which is the only time the problem shows up.
You and me both LOL. The tracking rate is set to “Auto” Perhaps I should change that to “Custom” and 1.00x sidereal.
Eliminating PHD2 should be straight forward - just use a profile with no guider.
Agreed though that eliminating SGP probably won’t be useful - you could though run PHD2 standalone, having it guide while the mount approaches the meridian flip zone.
I have been using a CEM120EC2 for almost 4 years and I only experienced this in the very beginning. There was a ug in he code that was causing flip issues just like you describe. That was corrected in a code release some time ago. Just out of curiosity what ver are you running?
Also I see in your sequence it is set to wait for meridian. It appears that you were using a 10Min sub. How close were you to the 10 min window? I have seen that flips while waiting for meridian have caused this issue. I usually set my Commander to 12º past to stop ( as a safe guard) and SGP to 5 to 10 minutes past to flip. Never had an issue with these settings.
Do you see SGP plate solve, PHD stop, and then tracking stop prior to the flip? That is usually what I saw when it failed. But like I said that only ever happened when I was waiting for meridian. When the flip occurred after the mount tracked past meridian it worked every time.
- you could though run PHD2 standalone, having it guide while the mount approaches the meridian flip zone.