[Ian Robinson]

I've been using my trusty old Tasco 60mm (f/15) refractor as a guidescope with my 10" newt. It's all metal , not like those junky later and moden Tasco refractors , mine actually focuses and has pretty good rack and pinion focusor with an extendable draw-tube that is all metal) and had a hard life .... isn't pretty to look at but still works a treat.

I've just ordered a Lumicon Coma Corrector (took ages to find someone who still had some) and have placed my order directly on Lumicon for a 2" Newt Easyguider + 2" Canon T - ring suiting the 40D, so I wont be using a guidescope for prime focus photography from much longer .

I will continue to use my old guidescope on "little" CG5 to guide, just need to rig up a home brewed Side-Side gizmo to do that.


I think for good guiding with a guidescope, the focal length should be near the focal length of the prime telescope or lens , preferably longer than the same, if you can't see a suitable guidestar in the fov , then it's easy enough to offset the guidescope a tad until one become available.