Odd guiding issues 1600

Mike Shade

Having odd guiding issues. PW 17CDK/AP1600GTO CP4/Optec Gemini/SBIG STL6303E. Win 7/Maxim 5.18/ACP V8, build 5/Focusmax 3.4.14/Sky6.63. The system will return round stars across the frame unguided for 382" (382" is the worm period) both sides of the meridian (PA=0), about 70 or so degree elevation (unbinned .63"/pixel). Telescope collimation is good. It will do the same, both sides of the meridian guided with both a 5" and 10" guide exposure (calibrating Maxim on each side). Maxim DEC compensation turned off (same in ACP), min move .02, max .15, correction delay .10, reverse X on meridian flip is on. Aggressiveness is 6.5, guider binned 3x3. Now here is the fun part. In ACP, will set PA=0 (rotater set to 0), run calibrate guider script pointed east (OTA on west side of pier). Guider calibrates nice "L" shape, movement is say 50. Will run a script, say NGC 5468, PA=145. It will run along nicely, flip the meridian and continue on the other side. All of the stars are elongated E/W, the images are useless (600" exposure). In looking at the guider log from Maxim, it seems that the system is making a lot of corrections in RA. Not big corrections (.02, .-03) but every few guider cycles. Do not see this in DEC, of course. I have checked everything I can think of. Plus the system will do unguided for 382" (suggesting that the PEC curve is good and the system is stable), and will guide through a worm cycle just fine on both sides of the meridian, calibrating prior to each. It seems that there is something with the rotator, Maxim, or ACP guiding. And there have been no updates or anything to software. This problem has been an issue for several weeks and I can't figure out what is going on here but dark time is being wasted. Anyone have any ideas or thoughts?

Mike J. Shade
Mike J. Shade Photography:

In War: Resolution
In Defeat: Defiance
In Victory: Magnanimity
In Peace: Goodwill
Sir Winston Churchill
Already, in the gathering dusk, a few of the stars are turning on their lights.
Vega, the brightest one, is now dropping towards the west. Can it be half
a year since I watched her April rising in the east? Low in the southwest
Antares blinks a sad farwell to fall...
Leslie Peltier, Starlight Nights

International Dark Sky Association: www.darksky.org

Join main@ap-gto.groups.io to automatically receive all group messages.