Guidescope or Off-axis?

[Mariner]

Another idea just popped into my mind but I'm not sure if it sounds too crazy. Current rig is a C9.25 F/10 SCT mounted on the iEQ45 and a non-modified DSLR.

Instead of imaging thru the C9 (w/focal reducer) and guiding through a guidescope, is it practical to image through the guidescope instead and guide through the main?



As beginner mentioned, most DSOs can be done through a FL of 400 to 700mm which can be covered by most guidescopes and the Short tubes are faster than 6.3.

Seeking opinions but would appreciate if suggestions do not dwell into the thousand-dollar equipment investments as I am not looking to "go pro", just take decent shots for personal collection and sharing with friends (outreach in a way).

[orly_andico]

Yes you certainly can.

The problem is the guiding graph will be extremely jagged when guiding through the main scope.

that said I have guided through the C9.25 native. it is doable with the AP600 (which has 10" p-p periodic error). I have not tried with the CGEM though. the iEQ45 would have 15" to 20" so might be possible.

[Mariner]

Another question on AP setup. Is it better to mount both scopes on a side-by-side dual plate or guidescope on mainscope via guidescope rings?

This

or this?

[orly_andico]

the side-by-side plate will add considerable weight. If you're using the iEQ45 + C9.25, I feel that the added weight of the SBS would overload the mount already. Best to use an OAG. Buy the TS OAG9 being sold here... cheaper than buying an SBS and you'd get better results.