Autoguiding scope choice: 66mm or 80mm

Hello everyone,

I am getting ready to try my hand at some imaging. I'll be using a Losmandy G11 with scopes from 500mm fl to 2000mm. I would like to use one of the small scopes I already have for the autoguiding. Should I use a 66mm w/400mm fl. or an 80mm w/550mm fl.? Is the extra 14mm of aperture and 150mm of focal length, worth the extra size/weight? Which would you use? Or am I off base and should use something else?!

Thanks in advance,
Ralph

I use an 80mm f6.25 as a guide scope with great results with my AT8RC on a CGE mount. The 80mm has a little more light grasp and the longer 500mm FL gives better guiding with longer FL scopes.

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Either will work fine but use which ever one has the most solid focuser. That will help minimize one of the many forms of flexure you'll most likely run in to with a separate guide scope.

Robert