This image rotates at the same rate as the earth (2.5 degrees counter clockwise over 10 minutes). Using a star tracker aligned with the X in this image will let you test the earths motion is being accurately subtracted.
This, as well as your manual barn door tracker video, are very, very helpful. The 'simplest' explanations on this type of astrophotography tools. Thanks a bunch! When I succeed in capturing the night's sky with my, yet to build, tracker, I will let you see the result. Thank you again!
thanks .... is this done with your motorised barn door tracker? I am better at math than physical engineering, so to program a motor with a raspberry pi to compensate for the barn door approximations is my expected route.
This is actually to help calibrate no matter what tech you use. So if you go your motorized math strong route, you can check if it works by photographing this video without waiting for a clear night to debug!