View Single Post
  #12  
Old 27-05-2011, 05:09 PM
gregbradley's Avatar
gregbradley
Registered User

gregbradley is offline
 
Join Date: Feb 2006
Location: Sydney
Posts: 18,185
Quote:
Originally Posted by Carl View Post
Greg Thanks for your input.
I'm using a canon 500d. with a celestron 6.3 focal reducer and flattener plus a radial guider bnetween. maybe i need to ditch the radial guider and have spacers .
I've tried imaging also with a 2 inch adapter between the radial guider and camera. From memory my distance from reducer to chip is around 100mm.

Cheers carl

Hi Carl,

You are using a reducer plus a flattener or did you mean reducer/flattener? They are 2 separate items and not the same thing.

Reducers reduce the F ratio for example in your case from F10 to F6.3.

Flatteners correct for the curvature of the lens/corrector/mirror and give pinpoint stars corner to corner. They usually don't affect F ratio or only slightly. Their job is to make sure stars in the corner are in focus at the same time as stars in the centre of the image. I was not aware of a flattener for an SCT.

Flatteners and reducers don't usually work together. So if you are using 2 separate items that may be your trouble.

Greg.
Reply With Quote