Focal reducer for 80ED?

[michaelmorris]

I presently use an Skywatcher 80ED (600mm focal length F7.5) for widefield imaging using a Canon 100D DSLR. I'm after a focal reducer/field flattener to help get better images. The obvious choice is the Skywatcher 0.85x Focal Reducer for Evostar 80ED. First Light Optics - Skywatcher Focal Reducers

It is designed specifically for use with this scope and provides a flexure-free screw-in connection.

However, I may (read 'will') upgrade this scope or the focusser at some time in the next few years and would ideally like not to have to add a new focal reducer to the budget. I will probably also want to use the focal reducer/field flattener with my Revelation 66mm APO (400mm focal length F6.0).

Can anyone suggest a focal reducer/field flattener that will fulfill these criteria?

Thanks

[Bizibilder]

I asked around about these recently and the concensus (on forums and from suppliers) was that the SW product is primarily a flattener that has the side effect of being a focal reducer. They are specifically matched to the scope and therefore cannot be "swapped about" (as was my intention). FLO sell an adapter that fits the 2" focusser, mainly to make altering the angle (of rotation) of the camera easier to do.

[michaelmorris]

The Hotech and TS field flatteners look interesting, but a bit pricey.

However, I've remembered that the Revelation 66mm APO only has a 1.25" focuser. Would it be worth swapping this over for a 2" focuser or would I just get bad vignetting?

[michaelmorris]

I've now got a Celestron f6.3 focal reducer. It's mainly for use on my LX200. It will come to focus when used with my Orion/Skywatcher 80ED. However, on the 80ED it will only focus if I bring the distance down from the recommended 110mm between the imaging plane and the back of the reducer to just 60mm. What effect will this have on the flattening bahviour of the focal reducer?

[dmahon]

Take a picture and shove it into CCD inspector (I believe there is a free trial). If your chip is small, it might be OK as the curvature tends to get exponentially worse towards the edges when it''s not situated at the right spacing.