Using a Bahtinov mask

[JamesF]

Let's say I want to get Saturn in good focus and with the webcam and barlow (perhaps even an extension as well) in the scope, use a mask to set up the focus on a bright star. So far, so good.

Without GOTO, and as I really don't want to disturb anything I've got connected up, are there any handy tricks for finding Saturn again? The margin of error with an RDF seems sufficient that I'd never be certain of getting it in the field of view. Would it make more sense to use a finder scope, or are there any other cunning methods I'm unaware of?

James

[Peter Reader]

I've had a good results at finding objects with my green laser pointer. You can pick them up on ebay for under £15.

[Dave]

For me, a well aligned finder cannot be beaten.

But it's still a challenge at times though.

[Psychobilly]

I used to use a cheap 8-24mm zoom which was parafocal with the webcam... I wouldnt adjust focus as it was only being used for finding the target... the FOV of the webcam is similar to a 6mm EP ...

[cgarry]

Even with GOTO it can be a challenging, as you will be more that aware the webcam sensors are very small.

I usually get close using my Telrad, then briefly swap out the webcam for an EP with a much wider FOV. Centre Saturn in the EP (well the unfocused blob that is Saturn) and then swap back to the webcam. So long as the focus is not touched then the webcam will still be focused.

Something like this http://www.firstlightoptics.com makes /proddetail.php?prod=vixen_flip_mirror makes the whole swapping process much easier.

Cheers,

Chris