Telescope mounting for imaging

[shaunster]

Would I encounter any problems if I mounted my imaging scope ontop of my guide scope?

As my scope has a diameter of 87mm the 90mm tube rings dont fit, do you think making them fit using something like cork sheet would cause me problems during long exposures?

Thanks

[Star Gazer]

Hi Shaunster

Sounds like you own a WO Megrez 72?

I am about to fit 90 mm rings to my Megrez which has an OD of 87 using cork (sticky back). I tried this out with some rough pieces and it seems rock solid, but the rings do need to be nice and tight.

I my case I don't have a guide scope, so may be its not so critical for me. However why not shim out the gap with some thing less compressible. Thin plastic sheeting from a model making shop would be great, or mar be even cut up an old credit card.

[ollypenrice]

It matters not a jot which one is on top. The prototype GEM from Astrotrac has an inbuilt guidescope (brilliant, brilliant, brilliant idea!) which is underneath the saddle plate.

As for the padding, you just have to be sure it won't induce differential flexure between guidescope and main.

Olly

[johnrt]

I've mounted my Meg 72 above, below and next to my ST80 guidescope - as Olly says it matters not a jot.

[jgs001]

Not a megrez 72,but I've done the same won't my C80ED and my St80, both one on top of the other and side by side.

[shaunster]

Thanks all, order some tube rings and thats me sorted