We were determined to get somewhere last night (Saturday). Unfortunately, the clouds rolled in late afternoon and things weren't looking good. I went outside a few times after tea to see the sky clouded over
Finally around 8 the sky was clear YAY! So I started setting up the mount and scope. I just bypassed the mount alignment procedure and swung around to suitable star, bright enough and away from the nearly full Moon.
I put the 24 Pan in to get the widest field possible and did a quick focus. The best I could obtain was a huge comet! So I defocussed the image. Instead of getting a donut, I got something more like a burger ring! The thickest part was about four times wider than the thinest...hence the problems. While I was waiting for my wife to come out to give me a hand, I thought I would give it a bit of a go on my own. So I chose a screw at random and turned it, anti clockwise seemed as good as any. When I looked it appeared the image was slightly less burger ring and more donut...so I turned a bit more and recentered. Eventually I could see it was about as close as I could get in one direction, so chose another screw. After a few more tweaks, it looked pretty good. Time to put in a shorter eyepiece. With the 10mm the image looked like a pretty good imitation of a donut.
Now I tried to focus the image, pretty damn good if I say so myself. By now my wife came out and I said I was nearly done. A couple more tweaks and I was happy
In total, I guess I had to move one screw nearly two full turns and half a turn or so on another (of course who knows how much of this was caused by the previous attempts).
So I decided to turn it onto something simple and move to Mimosa but as I tried to focus, I couldn't get it right. No matter what I did, I couldn't get it right.
I went back inside to try another eyepiece and on the way back I noticed the corrector was all frosted up!
You don't get problems like this with a Newt...
So next time I will put the dew shield on before I start to get serious. By now it was about time to come inside and warm up anyway.
So, morals of the story?
- If the alignment is REALLY bad and you can only see "comets" use the defocused method to get it into a ballpark. It works really well.
- When you are collimated, put the dew shield on (or turn on the heater).
Now I just need a clear night so I can reset the finder and laser centering and then I might even try aligning the computer for the first time....