View Single Post
  #11  
Old 20-04-2010, 09:05 AM
h0ughy's Avatar
h0ughy (David)
Moderator

h0ughy is offline
 
Join Date: Apr 2005
Location: NEWCASTLE NSW Australia
Posts: 33,428
Quote:
Originally Posted by JohnH View Post
David - which WO flattener are you using? I have a FLAT2 and 3 and find neither of them works very well on the 127 - in fact the Canon20D works better with no flattener in line.

I think there is under correction as your corner stars are

\ /
/ \


If I have this right this means the sensor needs to be further from the corrector - try a small spacer. If you get stars in the corners like this:

/ \
\ /

you are over corrected and you need to get closer unfortunately that is tricky to achieve with a DSLR.

How do your images look with no corrector in line? (BTW it is not a crime to crop a little if your field is not flat all the way to the corners)

Finally you may also get a better result by focusing on a star 1/2 way to the corner not one dead centre on the CCD as this will balance the focus better.
John thanks for your reply - it is version 3 i have. The information is great - and i will have a try at the spacers. have a look at a sample image i have withought a spacer http://www.iceinspace.com.au/forum/s...ad.php?t=59765
Reply With Quote