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View Full Version here: : Focal Reducer for a DOB


mswhin63
22-12-2009, 02:20 PM
Hi, I have been doning some mosaics for a while of the moon, but i am interested in doing some wider field stuff.

I purchaced a focal reducer from Bintel some time back, I believe it was to suit and SCT back in the days before I know what SCT mean't :P

Anyway, I would to know what is the best focal reducer for a 12" DOB, anything special needed?

jjjnettie
22-12-2009, 02:22 PM
I tried that with my 10" and couldn't achieve focus.
Borrow one for a test drive before forking out the $$$'s.

mswhin63
22-12-2009, 02:24 PM
I already purchaced it and as a collapsable DOB I lowered the arms and was able to acheive focal point but got a horrible blue tinge around the moon.

jjjnettie
22-12-2009, 02:28 PM
You can get rid of a lot of the CA around the moon by using a photoshop plugin call "Chromatic Abberation". The plug in works with photoshop, paintshop and the gimp.
http://www.tpo.ca/PS_Tricks/Various_Photoshop_Techniques.htm
Star Rounder is another very useful tool as well.

mswhin63
22-12-2009, 08:49 PM
Thanks for the assist JJJ