Quote:
Originally Posted by DavidTrap
I'm wondering whether it's worth the effort - I would need to add a modified dual axis drive to my mount, and an Autoguider, so it's not an insignificant cost. I've used a fairly simple technique for polar aligning my EQ3 for widefield work, with pretty good results. I'm hoping to do some stuff around 350mm, so autoguiding might be appropriate.
Basically, using a longish (200mm) lens, you take a 30 second photo pointing at a bright star near the zenith. For the first 15 seconds you slew one way at ~8x siderial rate (this is what the single axis drive on my mount does) and then slew back the other way for the final 15 seconds of the exposure. This produces a V shaped star trail. You then adjust the azimuth of the mount and repeat. If the V gets wider, you went the wrong way. When you have a straight line, you can swing out towards the horizon and adjust the altitude in a similar fashion. Probably best to repeat for both adjustments again before declaring it "polar aligned".
DT
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That works surprisingly well and is quite quick to implement. I set up my mount initially after the first solar\declinometer adjustments and then refined it using this method.