Hello Ray,
I have discovered significant RA drift after loading my PE curve and turning on the PEC in the Gemini L4. You had answered on my post in the gemini user group that there is a way to remove this drift in pempro although it will be trial and error. I can't seem to find the method or anything about drift removal in the help files.

Looking at my data that I acquired for my current curve under the Analyze tab, my X drift (X is RA axis)shows -0.013092 the Y drift is 0.003159. When I created a curve I did not check ether box to adjust for drift as I thought this only effects the display on the graph. Am I correct, or does this just apply to the Acquire Data tab? If I'm wrong would creating a new curve with this box checked help with my RA drift?.. I'm Just confused..

Secondly, I have a feeling that the blue tab in the Curve Tweaking box has something to do with the trial and error method you talked about, but I cant find any info in the help files on this. If there isn't and it is trial and error, could you give me a starting point or a general outline so I can start making the errors!

I have used Pempro for years on all my mounts and love it. I never had to get into any advanced settings, I never needed to. My current mount is an MI 250 with a level 4 Gemini. 4.6 ptp pe that is down to 1.8 ptp (with drift!) with pempro. I guess I'm just getting really picky with it, but I would like to try to eliminate the drift.
Thanks
Paul

Hi Paul,

I posted a response on the Gemini forum but maybe you missed it. There is a toolbox item on the Gemini tab which allows you to adjust the tracking rate by altering the curve. Take a
look at the very bottom of the help file for Gemini in the section "PEC Drift Compensation":

http://www.siriusimaging.com/Help/PEMProV2/gemini.htm

-Ray

Ray, thanks for the quick reply on both! I didn't see the other.
I was playing around with the Drift compensation box. What would be a good starting point? I tried to copy the X drift displayed in the Analyze tab,to the drift compensation box, and my ptp in the curve goes from 4.5 to 31.9!
shouldn't this be close?
thanks, Paul

Ray, absolutely amazing!!!! I added the drift compensation to the curve, it only took about 6 tries to get it spot on. It removed all my drift, a test image of 4 min unguided produced amazing stars! My guider errors are now less than .4, and the guider RA graph is just about flat lined.
THANK YOU.. for the help on this,
Paul

Hi Paul,

Sorry, I missed your earlier post somehow. The drift compensation value is usually a very tiny value - I'm guessing it is some sort of software calculation residual. As you found out it is not related to the actual drift.

Anyway, I'm glad you were able to remove the drift! It would be great if you could post back on the Gemini list that you were successful removing the drift. I think a few people might be thinking it's harder to remove the drift than it actually is.

Thanks,

-Ray