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Bit like an economists convention eh?
You don't just get "the Barlow" that works on all imaging systems - your Barlow must be chosen to match both your scope and the chip that you decide on - there will be quite different solutions for different cameras and scopes. the rule of thumb posted earlier pulls it all together.
As I see it, with that scope, your options are:
D..K21 618 - well tried and dependable - fairly large pixels so you will need a final FNo of about f28 - get there with a bit under 4x magnification with your scope (suggest 3x Barlow with extension tube). Then you will have a setup much like the one that Franck uses so effectively.
QHY5L2/ASI120 - quite new cameras, but some imagers are producing very good results with them at a bit under f20. these have smaller pixels than the DBK/DMK and do not need so much magnification - with these cameras, a 2.5x Barlow is about right with your scope (suggest 2x with extension tube).
Neximage5 - relatively untried, but has high spec chip - has tiny pixels and only needs a final FNo of about f11. - you can get there with a 1.5x Barlow on your scope.
Last edited by Shiraz; 03-04-2013 at 01:38 PM.
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