Focusing Prime Focus with a Powermate

[Afro Boy]

Hi folks,

I'm thinking of getting myself a 2" 2x or 4x Powermate for some closer imaging of the planets.

I'm struggling to understand the focusing aspects involved ... I have the normal focuser on the telescope, but then there is the distance between the camera chip and the lens in the Powermate too.

How do people go about adjusting these parameters? I can imagine it could end up being quite tricky.

Any thoughts or advice most welcome.

Cheers,

Af.

[Merlin66]

The Powermate is ideal. There's NO requirement to have the camera at any set distance behind the lens. The telecentric design will focus anywhere. You can buy a T thread adaptor which replaces the eyepiece end of the powermate and allows you to attach your camera.

I regularly use the x2.5 Powermate with a DMK41 for solar imaging on a SM60 DS/ ED80 set up.

HTH

[Afro Boy]

There's NO requirement to have the camera at any set distance behind the lens. The telecentric design will focus anywhere.

Thanks! That makes the whole set-up a whole lot easier in my mind.

I have a Stellarvue 105 f/6.2 triplet. I know it's not ideal for planetary imaging but I'd like to try to get better images than I already have of the planets/moon.

Would a 4x Powermate be pushing it for this scope?

Cheers,

Af.

[Merlin66]

A x4 powermate would give you f25.. this should provide a good plate scale for lunar/ planetary imaging. Check out your camera pixel size v's resolution.

[Afro Boy]

Thanks again for the advice.

With a 4x Powermate, I'll have a focal length of around 2600mm.

I'm using an unmodded 450D. Pixel size: 5.2µm, Resolution: 4272 x 2848.

[Merlin66]

You can use Ron's CCDCalc to check the image size and resolution.

http://www.newastro.com/book_new/camera_app.php

[Afro Boy]

That's a great help. Thanks for the link.