Difference between Focal Reducers

[Taff]

Hi' is the difference between focal reducers go by what type of telescope you own Thanks.Mark

[brianb]

Focal reducers usually have a field flattening function as well, this needs to be matched to the scope type & focal length if it's going to work acceptably. Note for example that SCT focal reducers do not work at all well with Meade's ACF scopes because the field flattening gets done twice!

The reducers sold for some refractors also have a coma correcting function.

[Taff]

Hi Brian' The scope i have got is a 8'' F5 Reflector.Mark

[brianb]

The scope i have got is a 8'' F5 Reflector

For imaging with a small chip CCD, one of the 0.5x eyepiece threaded reducers would probably be OK. But I wouldn't want to use a reducer with an f/5 scope visually - you're shortening the focal ratio even more, and most eyepieces are really struggling once you get on the short side of f/5. Visually the most useful tool with a short focus Newtonian is the Televue Paracorr, which corrects coma but also has a slight barlow effect (about 1.2x).

[Taff]

Hi Brian' Thanks alot for your time and help.Mark