off-axis guiders?

[Sammyb]

Hello - are these any good? I can imagine they might not be good for serious astrophotography but what about for beginners?

Can you get them to fit a Skywatcher 200P reflector?

Cheers,

Sam

[Revs]

I asked the same question and was told that they're good, just more fiddly. Why not use your finderscope?

[Merlin66]

I used off axis guiders for almost 15 years...they work.

On a newtonian you need a low profile type ie Lumicon.

Fiddly to set-up but when aligned and focused they do what they say on the box.

[steppenwolf]

Can you get them to fit a Skywatcher 200P reflector?

You'd have to choose wisely to get a very low profile one ideally with a low profile focuser on your Newtonian as these can be awkward with regard to back focus.

The concept of an OAG is a good one, the practicality of using them, less so! The cruncher here is what is known as 'differential flexure' (where there is unwanted movement between the guide camera and the imaging camera). OAGs help to resolve this issue as both cameras look through the same optics but it can be a pain to find suitable guide stars with an OAG as the FOV is somewhat challenged.

[Sammyb]

Hello - thanks for the feedback on these.

Following the suggestion above I'm interested in how it is possible to use your finderscope as an autoguider? The eye piece on this is very small.

Cheers,

Sam

[Revs]

Hi Sam. I'm using a QHY5 guidecam attached to the finderscope using one on these adapters..

Accessories @ Modern Astronomy

You simply unscrew the eyepiece and replace it with the adapter and cam.

HTH

EDIT: I've not actually have chance to use it for guided imaging yet as I only got it last week. But Bern assures me it's plenty good enough under UK skies and it's very easy to set up. With this method you have a bit of adjustment to move the finderscope about to find a suitable guide star, too.

There's a pic in my profile of the QHY5 attached to the finderscope.

[Sammyb]

Paul - thanks for the info. That's an interesting idea I will try.

Cheers,

Sam