Guidescope for 8" SCT

[multiweb (Marc)]

Originally Posted by 04Stefan07

I used to have an ST80 mounted on top of my tube as a guidescope. Although it worked ok and the weight is fine I never really got it configured correctly as a guidescope.

For those with an 8" or even bigger SCT what do you use for a guidescope and how do you mount it?

Thanks,
Stefan.

Unless you have some kind of mirror lock I'd recommend using an OAG for any SCT or you might find yourself limited in exposure time because of flexure, no matter how tight your guide scope is, your primary will always shift a little. A three point lock to support the primary is ideal. It supports it while still letting the glass expand and contract with temperature without stress. An OAG will follow a mirror flop, so worst case scenario will be a slightly tilted field but no star trailing over time.

[04Stefan07 (Stefan)]

Originally Posted by Camelopardalis

Stefan, I'd go for a bigger guide scope than the ZWO...something with more aperture and focal length. The Celestron package that Glen mentioned would be a better fit.

The thing with guiding is that you want to catch subtle movements before the main camera sees it. With the 1200D, the pixels are small and at >1200mm focal length you will readily see any guiding errors. The more light and detail you can throw into the guide scope the better IMO.

Yep that's what I did but that Celestron Guidescope pack is so heavy. It's around the 3 - 3.5kg mark.

[Camelopardalis (Dunk)]

Originally Posted by 04Stefan07

Yep that's what I did but that Celestron Guidescope pack is so heavy. It's around the 3 - 3.5kg mark.

Shouldn't be any problem on a HEQ5. The C8 itself is ~6kg. Your total payload shouldn't be much over 10kg by the sounds of it. Balance is most important.