Quote:
Originally Posted by 74tuc
Hi all,
About the selection of the focal length of a guide scope.
There seems to be a rule of thumb that states that the guide scope focal length should be a third to a half of the main scope. Can anyone point me to any link that actually shows how this rule of thumb was arrived at.
Jerry.  |
Understand where you're coming from Jerry.
There is quite a lot of conflicting information out there. Seriously, everyone provides a guide because in reality it is not possible to set a fixed rule. There are simply too many combinations - different telescope focal lengths, illuminated recticle eyepeice magnification, guider pixel sizes... it goes on and on.
What people don't take into consideration is seeing conditions, guiding tolarances and mount accuracy.
Perhaps its time for a reality check people. I refer to the following link -
http://www.aozc64.dsl.pipex.com/astro/guiding.htm