OK, so a few days back I posted about a couple clips I made so I could attach a red dot finder to both my camera and my Astra tracker.
See that entry for how I thought it should go, but how it actually went was I could not calibrate the scope. No matter how much I tried I got star trails even at 30 sec exposures, and the other night, just using an iPhone compass and level I was able to do 1 minute exposures with no trails.
So back to the drawing board. A person on thingiverse.com posted a shoe to attach the same red dot finder that I bought to the Astra. It has a lower profile and it looks like it will be far less wobbly than the one I made.
I do still need to adapt it to attach to my camera hot shoe, because I have no other way I can think about to calibrate the finder. It has 2 thumb screws one for fine adjust up/down and one for left/right.
To adjust to adjust those on the mount alone seems impossible.. You’d have to use the iphone to get a rough alignment, dial the scope to the north star, take a photo, see if it trails and then… what?… guess which way to move the mount and trial and error hunt for no trails?
No I figure if I attach it to the camera on a tripod, center a bright star in the camera view, which seems easy since there is a red box to center it in, dial in the finder, move the finder to the Astra mount, and well it should now be easy to point that at the north star.
It will take another sleepless, but clear, night to try again… I got up at 3:30am today, and clouds rolled in by 4:45, so also there’s not a lot of time to experiment in a cloudy region.
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