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Old 25-09-2012, 02:44 PM
mbaddah (Mohammed)
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mbaddah is offline
Join Date: Aug 2007
Location: Sydney
Posts: 803
Will this method of polar alignment with telephoto lens work?

I've been doing a bit of reading on polar alignment for my astrotrac and was thinking would the following method work.

1. Align tripod true south and set tripod head 34deg (Sydney) longitude
2. Mount SLR onto tripod head, and take a 30 second exposure shot using something like a 50mm lens
3. Playback screenshot, and home in little more using longer telephoto lens then previous focal length (say 70mm). Take another screenshot.
4. Repeat steps #3 until you have a reasonable focal length (say ~200mm) with the SCP always appearing in the centre of the playback shot without it drifting to the side of the lcd playback screen.
5. Remove DSLR, attach astrotrac, ball head, remount astrotrac on ball head and away you go!

Does this make sense ? Or is it total gibberish ?
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