Coma Corrector and Focal Reducer

[pixelsaurus]

Is it a good idea to mix a coma corrector ( for a GSO 300mm f/5) and a focal reducer together? I do like the idea of a 300mm f/2.5 to f/3.5 for photographic purposes. If OK, which order should they be coupled? Thanks.

[laser_jock99]

You can buy a coma corrector/reducer as a single optic: http://www.teleskop-express.de/shop/product_info.php/language/en/info/p4685_ASA-2--Newton-Korrektor-und-Reducer-0-73x.html not cheap but they do wonderfull work in the right hands! Not sure if you can use two different correctors together- worth a try but probably won't work.

[umadog]

I suspect you would need a single unit and that it would have to be made for a Newtonian similar to yours. These devices will need to deal with field flatness as well as coma, and both of these will differ across focal ratios and optical systems. Thus, focal reducers tend to be designed for a particular telescope type and focal ratio, as the unit linked to above is. You will likely also need a larger secondary in order to fully illuminate the larger field.