I found it worthwhile to tweak the gain and offset on the guide camera to optimize guiding SNR. For the ASI290mm mini with an IR pass filter a gain of 300 seemed to work well. Once the gain and offset are tweaked then doing darks helped further improve although if the offset was set too low dark subtraction gave poor results. With optimized gain, offset, and dark subtraction I get fairly robust tracking of stars.

Read More...