Quote:
Originally Posted by glend
This question also puzzles me as finding a guide star is often a frustrating process for me with a dedicated and adjustable guidescope. True the size and f ratio of the guidescope is a limiting factor and the larger aperture of the imaging scope gives greater reach but your always limited to the FOV. My solution that I built into my 10" imaging newt , was to get the Skywatcher guidescope mount which gives good x and y axis control to independently source a guide star. The guidescope mount provides a very large area to find a suitable star. Unfortunately the penalty for that wide field adjustment is weight, the guidescope mount adds about a kilo to the overall weight on the mount/scope. Once you add a larger aperture guidescope the weight goes up again. I use a ZWO 60mm guidescope, which is lightweight and can mount directly on the guidescope mount. As my 10" scope is light the additional weight is not a significant factor and actually assists balance by where I located it. I believe this is a good solution for light newts but would be not so good ehere your approaching the imaging capacity limit of your mount.
When I looked at OAG it appeared a more expensive proposition with the need to buy a more sensitive guide camera, special optical path adaptors, and more dependence on software, with inability to easily move it to my other scopes.
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I hear this story all the time and it really makes me wonder what people are doing! If you have a guidescope and you are adjusting it to find guidestars you are doing something wrong. Lewis proclaims with his ssag and a finder guider he couldn't find stars so he moved to a lodestar. This just simply isn't the case, I used an ssag with an oag for a while and while that was pushing it, it worked without adjustment. As far as oag being less versatile, when it's focused with the cam in focus you can take it to any other scope and you will be fine.
I like the onag solutions but it simply is not an option for any imaging newts where distance to the tube is an important vignetting consideration