Thursday, September 13, 2012

Testing the tracking mount

Finally there was a bright enough night to test EQ3-2. I needed to learn how to adjust it for this latitude and how to align it to Polaris. I have a polarscope but using that turned out to be more difficult than I thought. I got started with crude aligning to north without a compass. The idea was to take some photos with long exposures so I could see how long exposures I'm able to take.

First a test image without tracking:

The photo is taken with 300mm lens and 30s exposure and it looks like the lens was out of focus and the mount wasn't stationary all the time. However it gives an idea how much the stars trail with 30s exposures.

Another one with the tracking on:

Its about the same direction with 300mm lens (now with better focus!) and 30s exposure. Stars still trail a bit too much. Maybe 10s exposure is short enough?

Couple nights later I was able to photograph some more. And succeeded to align the mount better. This time I looked from a map where north is. :) 30s exposure looks like this:

Otherwise everything might be worse than the picture before, but I see no trailing at all. I wish I'd learn to align the mount like this every time.