Focusing for lunar photography.

Hi all.
I'm going to try a few lunar shots in the coming months.
I'd like to mount my DSLR in prime focus setup onto my scope.
I've got the T-ring & adapter on the way to me via eBay.

So I hear focusing can be an issue.
Simply put, what is the best method?

I've seen a few sites that advocate using a Hartmann mask which looks
quite easy to make. Although I'm still a little at odds as to how when you have focused on a star it means you will be focused for the moon also.

I'm guessing focusing using this technique is done through the eyepiece, then the mirror is flipped back for the shot.

Are electric focusers worth the money or is a flexi-mate extension nearly as good?

Plus, can people please stop buying new scopes.....
this constant cloud is getting out of hand.

Hi frank, the Hartmann mask is a great method. And easy to self-assemble (read - cheap!).

I used one with three non-aligned traingles cut into the face of a cardboard bought from Easons for 6 quid (the kind you use to mount picures on).

As regards focusing, you rack the focuser in and out until the three triangles (others use circles) merge into one. Well, the representation of the star you are looking at will look like three traingles - the idea is to merge them by focusing if you get my drift...

If you focus on a bright star, you will be focused for the moon.

You can do you focusing woth the dslr attached and not worry about flipping a mirror. Just take a picture, see the result, then refocus, then take a picture.... etc until you get a razor sharp image. then take off the mask and hey presto....

HTH

Dave

Hi ,
The hartman mask works well and is simple to make.
The flexi extension for the focuser is also handy as it stops things vibrating when focusing.I personally wouldnt bother getting an electronidc focuser for the etx, especially if there is backlash in the focusing mechanism (movement of the focuser without movement in focus)
At the start I'd try focusing by eye, especially with the moon as it is bright and easy to see, if you wear glasses make sure you wear them if doing this by eye, otherwise you'll never got a good focus.
Your focus is only as good as your eyesight if doing it this way.