Okay, so you are saying that guide Scope is sufficient enough then? I will look into those rings and mounts right now
I'm using a 90mm x 700mm for a guide scope just because I have it. The old theory of guide scope Fl mm was half of the main imaging scope. Some say 1/3 of imaging scope fl. I'm not a fan of the short guide scope except for short systems say below 300mm main imaging scope. A short guider should be good for a camera/lens guider tracker or some of the 70/80mm short scopes.
You can take any simple achro cheapie beginner scope and make it your guide scope. The biggest difference between a purpose built guide scope and a telescope used for a guider is the tube length and focuser type. On a dedicated guide scope the tube is longer before the focuser as it is intended to be used with out a diagonal. A telescope used as a guider might need an extension spacer between focuser and camera. Some dedicated guide scopes use a helical focuser for the camera. What you really need to watch out for is a sloppy wiggly focuser/ extender. It is most important to have a very stiff guide scope with no sag or shift in the camera holder/ focuser mechanism.
Any shift in the system be it in the guide scope and its mechanism or the mounting of the guide scope to the imaging scope and the imaging main scope itself including the main scope focuser/ flattener/ camera attachment will degrade your tracking. Everything has to be solid and rigid or you will be chasing demons.
On 1000mm plus imaging scopes some astrophotographers like the Off Axis Guider - OAG system, but they present some limitations too and are a whole separate subject. OAG guiding is particularly useful with a mirror type telescope that may present mirror shifting while imaging. In this case any optical train movement (minor within reason) will also be seen by the guide camera and corrected out in real time.
Im using the 700mm guide scope on a 1200 mm and a 980mm imaging scopes and keeping everything stiff it works well.
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