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Old 29-12-2018, 10:31 PM
SuperG
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SuperG is offline
 
Join Date: Oct 2014
Location: Sydney, NSW
Posts: 120
Best Focal Length ratio for a guide scope

I have two main scopes. The first is an ed80 with a zwo 60280 guidescope. I normally get good imaging results with little effort for DSO.

The second is a c6 SCT that I normally use for planetary. But I have tried to use it for DSO a couple of times now for increased resolving power with an f6.3 FR and an Orion 50mm mini guider (FL= 160mm). But the results are horrible. I have heard of flexsure but no one has ever explained that either.

My real question is what is the optimal FL ratio for a guidescope: imaging scope. I have heard the minimum is 1:5. Please provide comments.
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