Jump to content

1564402927_Comet2021Banner.jpg.a8d9e102cd65f969b635e8061096d211.jpg

Which Focal Reducer?


Recommended Posts

OK, so my first attempts at imaging have been not so great. I am looking to get a focal reducer for my 6" SCT F10 1500mm and cant decide if i get 3.3 (F3.3 495mm) or 6.3 (F6.3 945mm)

I have seen people making masks but i think ill end up just buying one... then ill have to work on my alignment some more i guess..

anyone used a focal reducer on a SCT of this size? any possible problems with going as low as 3.3?

Thanks,

Colin

Link to comment
Share on other sites

Yes the 3.3 is a horror dating back to webcam sized chips in the early CCD days. Keep away! If it were as easy as that to create an f3.3 imaging rig you wouldn't see all those little apos out there imaging away.

SCT imaging is difficult. An aftermarket Crayford is also a good idea but all these add ons add up. The long focal length will require accurate tracking, which means good autoguider, good balance and good polar alignment.

Olly

Link to comment
Share on other sites

f/3.3 reducer is for CCDs smaller than 2/3" (2/3" is max). f/6.3 provides imaging circle for APS-C sized sensors (DSLR and others). For guiding - OAG will be most effiecient (as you are using quite big focal length). I used Celestron Radial Guider with C8 at f/10 and f/6.3 and now I'll try to use that with C11 :)

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.