The last two nights my sequence finished with the same thing happening. After successfully guiding and shooting 18x20 minute Ha photos of the Heart Nebula the last image of the night has done the same thing two nights in a row. For some reason there is this huge spike in DEC and RA in PHD and the sub ends up looking like this.
I have included a screen shot of PHD, the SUB in Question, and the last portion of the Log File from PHD. I cannot tell if SGP is sending a park command prematurely or if PHD is the culprit. I’m reading in the log that a move scope command is being sent and then it won’t do it because it says an IO device is preventing it from happening.
Either way it’s a pain in the backside. This has never happened with my NEQ6 and was wondering if anyone could take a look at this and tell me what you think.
This has happened to me on occasion. I figured it was due to my cables which hang off near the end of the camera and attach on the pier near the mount, creating a loop that hands out. Keeps them from binding on my AP900, but there may be a price to pay. (I cannot afford an AP1100.)
Posts with pictures showing cable solutions on mounts like the AP900 that do not cause such problems would be most welcome.
Yeah I thought about that but I don’t have any cables hanging down. My entire rig is cable managed. I have a video out on YouTube on how to do it.
So thats not it. I wish it was that then it would be easy to fix.
I cannot for the life of me figure out what caused that huge spike like that unless my mounts gears got caught up or something. I wonder if I’m balanced too heavy on RA and its got a tight point that it works through. hmmmmm
Looking at the image and the PHD screen shot it looks as if the offset increases very smoothly and consistently in both(?) axes and from what I can see when it recovers the stars in the sub frame have shifted. They show as a bright streak that becomes fainter and changes to a series of points, then shows another bright star. I’m interpreting that as a move in the right and down direction. It gives me the impression that PHD is getting star position data that has, for some reason become offset.
I wonder if there could be some external influence, were you imaging the same object on both nights and did the error happen at the same time?
Could there be something like an overhead cable that the guide star is passing behind?
I have experienced this with an AZ-EQ6 with careful cable management. I have guide logs that show RA running slowly, but not stopped during the devaition, and others showing RA running fast during the deviation, sometimes on the same night, on the sameside of the meridian.
I found I could work around the problem by driving the mount forward 90 degrees from the park position, and then releasing the clutch and manually parking the mount, and power cycling to ensure it realised it was indeed parked.
I found forum posts suggesting that various pieces of software caused this type of problem (Stellarium?), but could not confirm any culprits.
My diagnosis points to the mount controller board.
Good luck working through this frustrating problem.
Ed that setup is beautiful. My C11 and RC8 look like that but pretty much stop there because I don’t have that super mount you have!!!
I’ll post some photos of my 3 rigs when I get back in front of my computer.
Tom,
Thanks so much for your response. I had a lightbulb moment when I read it. The last two nights prior to last night when this happened I indeed had Stellarium open and connected during those two nights. Last night I did not have it connected. I normally don’t use it anymore but I had some time on my hands between targets those two nights and wanted to surf around so I connected to it. It did not take place last night when I was not connected to it.
The only other weird thing was that when it happened both times it happened on the last two images at 4am when I was imaging the Heart Nebula up towards the Zenith.
Good stuff. I’m hoping to get out tonight but the wind is picking up and some clouds from Hurricane Irma are finding their way here tonight. Stupid Hurricane.
I’ll keep you posted but please keep the thoughts coming. Pictures too.
