Crossing the Meridian
Have you ever stood by the window looking out at the sky and wondering if the sky conditions where worth going out and setting up your scope? I think this story just might help you decide why you should go out on a semi-good night, if for no other reason than to hone your skills for when that perfect observing/imaging night does appear.
I let several semi-clear nights go by because it was not completely clear. I could have done some fairly good imaging through the large holes that where floating overhead, but I am getting somewhat spoiled. I didn't want to spend the required 20 minutes to set-up my equipment. To bad... so sad.
A perfectly clear night came out of nowhere and it was a great opportunity to catch an asteroid (7 Iris) whizzing past M-104. I went through the usual routine, set the scope up before sunset, leveled, balanced, installed camera, booted laptop, tested remote shutter, set focus, checked cables. All good. I then went back inside and waited for dusk. As the first stars came out very crisp and clear I hurried to finish getting ready. Polar alignment, 2 star alignment - check and sync.
Well jumping the gun here I ended up polar aligning to the 'wrong' Polaris! Then I slewed to the 'wrong' Arcturus! It was still fairly light out, and lacking the dimmer stars, it didn't really occur to me that I was on the wrong track. I then slewed to what I thought was Dubhe, which was centered right in the middle of the field. Great! Everything was moving along very nice (I thought).
I tested the camera and saw a blue star, Dubhe is orange! Houston we have a problem! I then put the finder scope on to check position, and I discovered I was pointing at Alioth. Ok... start over with alignment. Put scope back in home position and run through it again, this time with the finder scope in place.
Hmmm... 1st alignment star was not in the finder. By this time quite a few stars where shinning. Put an eyeball on the polar axis and discovered I was way off! I reset polar alignment to the correct pole star. This time the 1st alignment star was in the finder field but still a bit off. Now what? Rechecked my setup. I had the wrong date entered in the Autostar. OK, powered down and reset with correct time and date. Now we were getting somewhere!
Alignment went like a snap! I then quickly centered on my target and starting shooting pictures. Elapsed time so far, 1 hour and 20 minutes, or 1 hour wasted of perfect sky.
I set the camera on auto to snap a shot every 10 minutes for the next hour and walked away. I then came back to look at my images just before the last shot. I had some good shots, until the last one. My stars looked like sea gulls flying through the screen! The drive motor was hitting against the mount. The scope had crossed the meridian and needed to be flipped to the other side. Just when I had everything working so well!
So why should you go through all of this on a semi clear night? So you can be ready for that great clear night. Practice makes perfect and just when you have everything working, be ready for that next problem, it could be just across the meridian!Published in the July 2008 issue of the NightTimes