Guide stars

[Lee]

When guiding through a second OTA..... Is it advantageous to be guiding on a star near the imaged object? If so, how near?

[[1ponders] (Paul)]

The closer the better Lee.

If you had absolutely perfect alignment with your mount and scope and camera and all the bits and pieces orthagonal you could theoretically guide on any star in the sky.

However perfection is not always the case (except with the G11 of course ) The more poorly polar aligned you are and the further from your image you are (mainly in declination but RA comes into it too) the sooner you will get rotational issues in the outer limits of your image. The field of view comes into it as well. If you are imaging with a large fov with a long focal length then rotation will happen more quickly as well.

[Lee]

Thanks Paul.... I've just mounted my ED80 on top of h0ughy's C8 - initially to guide with the C8 and image with the ED80.... without a side-by-side dovetail, the ED80 is riding high!
After some googling/IIS searching, I'm just worried about mirror flop now!

[h0ughy (David)]

LOL no mirror flop in the ED80 - the c8 should be OK as long as you don't image for too long on the one object - you will need to check the focus every once and a while as it does change with temperature. Gee what a whinger - coupla bricks - no worries LOL. the setup now is preferable to a side by side, but if you throw a camera into the mix you will need one. Bintel have ordered 2 side by side units - I have one spoken for, not sure about the other?

[Lee]

Might be a couple of side-by-sides heading to the Hunter in a couple of weeks

Lucky I have a mini step ladder