Focus on the moon? - Forums

Topic starter

Jul 4, 2023

What is the best way of focusing when imaging the moon (and planets)? How do I know when I have the best focus?
When I image DSO-objects I use a Bathinov-mask or some focus software to help get the best FWHM/HFR-value.
But on the moon and planets?

++Håkan Wahlberg ++

Well Written Engaging

andrea tasselli

Frequent contributor

Jul 4, 2023 · Edited: Jul 4, 2023

Eyeball mk.I usually does the trick. If it looks sharp then it is in focus.

Well Written

Ed Dixon

Jul 4, 2023 · Edited: Jul 4, 2023

The focus setting for the Moon vs other stars is perhaps ever so slightly different, it is unlikely to matter in any AP efforts. The Bat mask focus will likely work fine. That said, focus can change over time as temperature and scope gear change somewhat. So one needs to check focus more often to be sure.

It's also the case that larger scopes may vary more as just the action of slewing from a bat mask focus on a star may change things a bit. I usually start with a bat focus and then, stay on the Moon and eye ball it from then on.

Helpful

Hwahlberg

Topic starter

Jul 5, 2023

Thanks. Well this is more or less the way I focus today, so I guess there is no better way than use my eyeballs.
And as a complement, I change focus slightly in and out to get different focus and pick the "best" video.

++Håkan W++

Robert Gillette

Dec 5, 2023

For me, nothing does better than using a B-Mask to focus on the brightest star I can find. And the result is essentially perfect. Eyeballing the moon doesn’t come close, at least for my eyeballs.

CS, Bob

Oscar

Dec 5, 2023 · Edited: Dec 5, 2023

What I would do in this situation is just focus in and out multiple times, because the first time you eyeball it, you'll probably overdo it, then just start slowing down and lessening the in-and-out focusing thing until you get closer to complete focus, and when you think you cant get any closer, just stop right there.

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Comic twist (ignore if you aren't interested):

Random guy (not you, of course) with his telescope in the backyard:
Instructions unclear, eyeball was engaged, did the in-and-out focusing thing, moon turned out unrecognizable, telescope is in pieces, currently cross-eyed.

Engaging