Calculating focal lengths with reducers.

[Neo_uk]

Hi...

I wondered if any of you kind people could tell me how to calculate the focal length of a telescope using a focal reducer ? ...I.e native focal length 600mm and a .85 reducer and 715mm using a .79 reducer ...just struggling to get apt to plate solve and I think it maybe because I have the telescope native focal length entered instead of the focal length while using a reducer. 

Any help would be greatly appreciated..

Chris.

[JoshHopk]

Hi Chris,

To calculate focal length with a reducer, you simply multiply the native focal length by the reduction factor. For your 600mm with a .85 reducer, the new focal length would be 510mm (600*0.85) and for you 715mm and .79 reducer, ~565mm (715*0.79).

Hope this helps,

Josh

[fifeskies]

Just multiply by the reducer value.

600mm with a 0.85 reducer is   600 x 0.85 = 510

715mm with a 0.79 reducer is   715 x 0.79 = 564.85  (use 565)

 

EDIT Josh beat me by seconds

Edited February 23, 2021 by fifeskies

[Neo_uk]

Hi ..

Many thanks for the replies !

This has helped me out alot ..as we know clear skies in the UK are far and few between and last night was a complete wash out ...

Found a excellent tutorial on here about apt so going through that now ..

I always thought of my self as tech savvy but the older I get ...the worse it is 🤣.

Many thanks again Chris.