CCDAP3 properly positions our telescope from the target list. However, when it does either a position realignment or a re-focus it positions the telescope ~7 arc min to the east of the target. I have attached the log file, but I copied a portion below.
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03:26:18 Telescope RA: 17 07 06.0, Dec: +07 46 00
03:26:20 Realigning scope to Target...
03:26:21 Slewing scope...
03:26:24 Slewed to RA: 17 07 31.1, Dec: +07 45 04
03:26:24 Mount settling for 50 sec. after slew.
03:27:14 Plate solving...
03:27:14 Telescope RA: 17 07 36.0, Dec: +07 45 00
03:27:41 C:\RK-Data\Mar-20-21-2008\CCDAutoPilot_SyncImages\SyncImage_WZ-Oph_032741.fit
03:27:43 Solved RA: 17 07 11.1, Dec: +07 45 52 PA: .0
03:27:48 Sync'd to RA: 17 07 36.2, Dec: +07 44 56
03:27:48 Telescope RA: 17 07 30.0, Dec: +07 45 00
03:27:48 Telescope reports RA: 17 07 30.0, Dec: +07 45 00
03:27:48 Pointing error (arcmin): RA 1.3; Dec -0.1
03:27:48 Slewing scope...
03:27:50 Slewed to RA: 17 07 31.1, Dec: +07 45 04
03:27:50 Mount settling for 50 sec. after slew.
03:28:40 Sync'd
03:28:40 Realignment complete

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At 03:26:18 the telescope is very near the target (a realignment really wasn't needed).
At 3:26:24 It slews the scope to the east. I have no idea where these coordinates come from.
CCADP3 then determines a pointing correction and
at 3:27:50 slews the scope to those bogus coordinates.
It did this repeatedly all night.

Does any one know what is going on?

Ron Kaitchuck

ccdap20080406_022300.log (88 KB, 112 downloads)

Hi Ron,

I notice you have correcting slew with sync checked. If you have a Tpoint model in TheSky, you should either uncheck "with sync" or disable the Tpoint model. They will fight each other.

We are not using T-Point.

Any other ideas?

Ron

I need to do some local testing, weather permitting. Should be able to test tomorrow night.

So further info:
T-Point IS installed on our computer, but never used. And it is "unchecked" in the Sky.

The telescope points well enough that the CCDAP3 sych option could be skipped. I just thought it was a good idea to use it.

Ron

Hi Ron,

Well, if you have a Tpoint model, why not use that and turn off the sync option? You will still get correcting slews but without the sync complexity. Most CCDAP users operate that way quite successfully.

Ron,

I just ran 6 unguided exposures with precision slew w/sync specified to occur after every exposure. The max error over 6 exposures was under 4 arc-sec. I don't know what is going on with your system but CCDAP seems to be operating properly. I used a 14.5" RC with a U16M camera at an image scale of .56 asp.

There may be some hysteresis in your optical system (mirror movement for example) or in your drive mechanics that exacerbate any sync-and-slew movements. As I suggested above though, if you have a Tpoint model, I would use that and not use the "with sync" option.