View Single Post
  #12  
Old 06-12-2011, 10:47 PM
gregbradley's Avatar
gregbradley
Registered User

gregbradley is offline
 
Join Date: Feb 2006
Location: Sydney
Posts: 17,877
I can't comment on the QHY9 but I have never seen anything other than perfect stars in any binning with my FLI ML8300. So I think the statement the KAF8300 has horizontal blooms is more of an implementation error by the camera maker.
I think the antiblooming level can be adjusted and its probably more that this has not been set at the right level. I know you can adjust the antiblooming level of the STL11 KAI11002 so perhaps the KAF8300 can be also. Worth asking about.

Also the bulk of those horiztonal bloom images are tracking errors.
If your tracking is good for say 2 minutes and then you get a group of bad PE then the star will shift for a while and you get a 2nd sharper star sticking out the side of the larger star (which got exposed the longest).

I have seen plenty of those but only when there were tracking errors.

Also binning 2x2 may not be 4x the sensitivity as you may expect as commented here on the way the registers are handled but there is a gain.

From personal use estimate something like 2X gain. I have gotten some pretty stunning Ha images this way so don't write it off.

If the seeing is poor you may be better off shooting luminance at 2x2. The KAF8300 has the smallest pixels of the current crop of Kodak sensors so there is a lot of resolution available there. Shooting Ha at 2x2 works well as often Ha only adds colour and contrast rather than detail.

I have been using mine for 3 years.

One thing I have noticed is the small wells on a fast system will overexpose stars that can wreck the brighter stars in an image and even lose some colour data. In that case I found limiting exposures to 5 minutes solved that.

Greg.
Reply With Quote