Jane C

Ultimately, I made a movie last night of Jupiter and Io. Eventually I propose to plot the position of Io against time. Local seeing was good, transparency was not so good. I eventually upped stumps because of cloud. Thinking about it, I am beginning to doubt the mirror movement hypothesis. First I focused and checked collimation on Artcurus, with scope east, counterweights west. I also then realigned the finder. Then I slewed to Albireo to get an image of the double to calibrate my photos for size in arcmin (the two parts of Albireo are about 35.3 arcmin apart). Here the scope was west, with counterweights east. The I went to Jupiter. The GOTO put the scope to the west and the counterweights to the east. Throughout all this the finder worked fine. Then I realised that I was going to hit the limits as Jupiter "moved" west, so I did a meridional flip. That's when the finder went out. Not slightly out. Miles out. By the time I had found Jupiter in my main scope, and checked the finder scope, Jupiter was right at the edge of the finder's field of view. So I think it's the finder. I also do some galaxy photography from time to time. I don't even try to find those in the finder. Instead I use the Celestron mount control software CPWI, and use a variant of star hopping. The software improves its "model" of the sky every time you tell it you have found your target. So I start with bright nearby stars and star-hop to less bright ones until I have calibrated the software on stars all around the galaxy. Then I slew to the galaxy. That usually works. Jupiter & Io 2021 09 04 B.avi

Interesting. Mirror flop is believable as I also had to refocus. Perhaps the answer is two finders, one for each side of the meridian?

Hi: I am losing patience with the inability of my Celestron 50mm finder scope to maintain its alignment during a meridional flip. I know all about the secret nut to tighten the finder once aligned, but this does not fix the problem. Therefore I want something more dependable. I'm thinking about a red dot finder, and would be interested to hear other users' experiences. My scope is a C11 XLT Schmidt Cassegrain. Thank you in advance, Jane.

Hi: I am really fond of Registax 6 and it does a great job, but for one really irksome problem: the backgrounds are too light for an imaging PC. The opening screen has a lot of white background, and when you are using it, there are too many parts of the screen with white & light grey backgrounds. They ruin the dark adjustment of your eyes, and illuminate the whole environment like the proverbial whorehouse on a Saturday night. That's not a good look when you are observing. So, either: Please can anyone tell me how to make these regions dark, preferably black? Or: Is there an alternative that's equally capable? Thank you. Jane.

This worked for me. I reset to defaults. Job done.