Quote:
Originally Posted by Saturn%5
Hi Nightstalker,
The mount is a Vixen Super Polaris with Dual tracking motors, not sure what the scope is for is for an yes as Jason has said that guy in Japan is looking like he will be getting getting a new customer.
Cheers
Graeme.
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Hi Graeme,
I don't know what the design objectives of this scope were, particularly with a .965" focuser drawtube. Although that size was common 30 years ago on smaller commercially built scopes.
The main advantages of a sled focuser design are in fact for photography. It allows for a much greater focuser travel range than is possible with a vertically moving focuser tube. It also allows the focuser tube to be much shorter in length and closer to the telescope tube making it stronger and able to support the weight of the camera better. Also the design makes it very easy to incorporate a filter slide into the back of the focuser.
The negatives, and they aren't really negatives for photography, is that you need to use a larger secondary mirror than what is required with a vertically moving focuser. This is because you need to size the secondary to fully illuminute the field at the bottom end of the focuser travel range, at which point the light cone is wider. The second one is that you have one fairly think spider vane.
Cheers,
John B