Plate solve moves to wrong location

[yomamma]

My sequence ran the first plate solve fine and I imaged for a few hours. Then I moved the mount and plate solve got lost.

I moved from the Helix Nebula to the Cocoon Nebula at about 1 AM on 9/6 and the move seemed to work correctly but the plate solve moved the scope off of the target. The Sequencer states that

Info 01:03:02.967767 #1 Before Sync mount is at RA=21:53:25,Dec=+47:16:09

This is the correct location RA 21 53 25 DEC 47 16 09 this is what was entered in the location to move the mount. Then the next Sequencer event

Info 01:03:03.996182 #1 After Sync mount is at RA=22:01:30,Dec=+46:58:39

Focus was great and I always wait (70 seconds on a 30 second frame exposure for plate solve purposes)until an entire frame is processed before calling platesolve so no streaks.

Why would plate solve move me so far off of the target and think it was correct? Could my mount clutch have slipped?

Lol I have 3 hours of deep space. Pretty stars.

Thanks for your help

[admin]

Hi,

could you send me the full log please - the results from the plate solver and the relative times might help me track down something of interest.

SharpCap should wait for the mount to stop moving and for a frame to be captured before plate solving, but I will check from the log whether it is likely to be bypassing that somehow. There is also an option in 4.1 to specify the mount settle time to allow more time for the mount to reach its final position before moving on to plate solving in case the ASCOM driver reports the slew as being over too early.

cheers,

Robin

[admin]

Hi,

thanks for sharing the full log with me. Looking at the plate solve operation in question in the log, which you mentioned was the first after the mount had moved to the other side of the meridian, I noticed a couple of things

1) The operation requested was to plate solve and sync only (MOUNT SOLVESYNCONLY) - I don't see a re-goto after the sync to re-center the target, so it's expected that the plate solving does not correct the object location in view

2) Since this target required a move to the other side of the meridian, it's not a surprise that the pointing was considerably off (particularly likely if you have cone error as the cone error acts in opposite directions on opposite sides of the meridian). It looks like the offset was about 1.4 degrees from the plate solving information.

Overall, my guess is that you meant to have 'MOUNT SOLVESYNC' for the second target GOTO, as you have that for the first target

cheers,

Robin

[yomamma]

DOH!

Thanks Robin.