Squaring a focuser

[KathyNS]

About a month ago, I installed a new FeatherTouch focuser. Evidence in recent images suggests that I need to tweak the focuser tilt. The FT has adjustment screws for this purpose.

How do I go about doing the adjustment? Test images or eyepiece viewing? Long or short focal length eyepieces? Use a collimation cap? An suggestions or procedures welcome.

Oh, it's an f/4 Newtonian.

[DEnc]

CCDInspector can help you evaluate any adjustments you make. There's a 30 day free trial--maybe you'll get lucky with the weather. (I wasn't!)

[turboscrew]

I just did something I learned somewhere in the web: I used a wide paper band around the telescope for finding out the exact opposite of the focuser hole, and I drilled a 1.5 mm hole there. Then I put a piece of isolation tape on it. When the secondary mirror is out, it's easy to check the focuser with a laser - if the beam hits the hole.

I used baking paper cut in half height. Wide enough to not tolerate much bending if the ends are connected with good overlap. I used the "factory edge", because I'm not so handy with scissors.