Friday evening was clear with some haze low in the sky, but, with Ursa Major high in the sky, presented an opportunity to try imaging M81 again. The CG-5 mount had some problems with intermittent tracking resulting in a lot of trailed images which had to be discarded and the corrector plate of the Celestron 9.25″ was fogging on the inside due to the high humidity. None of the images obtained were of good quality and I suspect the secondary mirror had fogged as well.
Despite the problems, 19 2 minute images were stacked and processed for this image:
Much more detail is apparent than in my earlier attempt. The Celestron is now drying out in a room with a de-humidifier running so hopefully the fogging problems won’t be repeated next time out.