STT Self Guide Filter Wheel and Guide Star Faded [merged threads]

[Bill McLaughlin]

I think I have fixed this and it may be a MaxIm DL question but wondered if anyone has seen this. I was running a sequence tonite and everything went smoothly for the first 5 or 6 300 second exposures. Suddenly when ACP had finished it's guide star dither and commanded an exposure, the guide star became only a bright pixel and I started to get a guide star faded message in MaxIm. The guiding also went to the dogs.

I then tried guiding just in MaxIm and got the same thing. It was fixed when I changed the guide exposure time (which forces a new dark frame when you have it set to the default, which is "simple dark"). It appears that somehow MaxIm is misapplying the dark or maybe applying it twice since disabling the simple auto dark seems to have fixed the problem.

Anyone seen this?

[John Batts]

I've been unable to calibrate my off-axis guider since upgrading ACP v7 and MaxIm to 5.23. Like Bill, I'm also using a SBIG ST-8300M with their off-axis guider (with an ST-i camera) ahead of the filters. The guider successfully calibrates in MaxIm, and guides on both sides of the meridian with MaxIm. If the guider is calibrated on the East side in MaxIm, ACP can image on the East side, but not the West, just as expected.

What's suprising though, is that when CalibrateGuider was run from the console (before I read this thread), ACP just reported "Calibrating guider ... Done" and didn't make any attempt to calibrate. But after reading this thread, and selecting the External Guide Scope preference, the scope now slews to a mag 6 star, then reports "Calibrating guider ... Done" again without calibrating. Has anyone else had similar issues, or have any suggestions? Thank you!

[Bob Denny]

Do you have a rotator?

[John Batts]

Not sure how to answer ... The telescope is an FSQ-106EDX, so both the camera and OAG can be rotated manually. What surprises me is that (a) CalibrateGuider doesn't even take an initial image, let alone the 5 needed for calibration, and (b) it successfully calibrated in v6 regardless of the rotation of either the camera/OAG or the guide camera (the red cylinder) in the OAG. Maybe the attached photo will help.

8300+OAG.JPG

[Bob Denny]

OK, no rotator. So set it up as an external guide scope. I did make changes to CalibrateGuider but just to refuse to calibrate if the telescope is looking west. ACP's convention requires it to be looking east. Maybe when you did it in ACP 6 it was looking east?

If it is looking east and it won't calibrate, then calibrate it in MaxIm manually. That should be fine. You will have to do this each time you rotate it manually. Just so you know, adding a rotator (Optec?) will make your life vastly easier

[John Batts]

I did accidentally try to calibrate in v7 looking west once, got the error message and the script terminated. But with that exception, every other attempt has been looking east, and no error message. Just "Calibrating...", "...done", "Starting slew to Cal return..." without taking any calibration images.

From now on I'll calibrate in MaxIm. I just didn't know if ACP used MaxIm's vanilla calibration, or whether ACP performed an uber-algorithm like it does with guiding. And thank you for the rotator advice ... will do!

[Bob Denny]

ACP just calls MaxIm's calibration function as though you clicked the cal button. I would like to see this though, and report a bug if it exists. Mu evening schedule is uncertain for several days but can you give me some times that would work?

[John Batts]

I can be available any evening through Wed 6/5, although at present, Sat - Mon nights look clear. It snowed last night here - John

[Rick Stevenson]

I have seen exactly the same problems that others have mentioned with ACP7 and OAG without a rotater. Calibration often fails silently and without taking all the usual calibration images (seems to happen when there isn't a bright star in the guider field?) Also, I can get guiding working perfectly to the East but corrections rapidly push the scope in the wrong direction when guiding to the West. Messing around with guide angles, etc. doesn't help. I'm in the southern hemisphere BTW.

Guiding works fine with calibration in Maxim so that's a good workaround. Just thought I'd mention in case it helps find a problem/fix.

Cheers,
Rick.

[dennishohman]

Hi John,

I normally position a guide star on the guide chip before starting the calibration run. This has worked for me for version 7. Also, if you you use the OFF-AXIS setting make sure to put the Position Angle derived during calibration (From MAximDL guider settings) into the PA box in the ACP guider settings or guiding directions may drive the star off the guide chip. In the ADVANCED guider settings in Maxim I keep the X-Y reversed when crossing the meridian checked.

Dennis