[little col]

Originally Posted by iceman

Hi Col.
Probably a combination of sky pollution and the modded 350D.
What do longer exposures, or more exposures + stacking bring out?

Do you capture in RAW?
What's the WB set to?

after the stack it was a white colour and i was imaging in jpeg auto white balance

Originally Posted by Zuts

Hi,

I wouldnt worry about the cast. I image from inner city sydney and have tried an orion lps filter (orange cast), atronomic UHC filter (blue cast). I think all filters give a cast to the LP in the sky background.

I just stack as many photos as possible and process the cast out with PS2 (or equivalent). Also since you have severe LP i would consider capturing at ISO 400, so you will be able to expose longer, stack more subs and rely on PS2 to bring out the details.

Paul

cheers paul i was going to get a narrowband filter but as you say it might not be that beneficial

Originally Posted by Tamtarn

Col you posted this image on 12/12/07

30sec ISO800 same camera same scope. Looks great. What have you changed since then??

Attachment 39248

ah yes i remember this , if i remember this was taken from a darker site and i processed the balls out of it to get it as good as this

Originally Posted by JohnH

Hi Col,

I have been experimenting with an NBP fiter recently for imaging - it also produces a color cast. To get back to a "natural" colour balance I have found using the RGB curves in PS to be the most effective - adjust the curves so the peaks for each color are at the same point on the x-axis and the colours seems to be "natural". There may be better ways - eg use of a standard "white" star in the image (gv2 class) or using a white/grey card and setting your camera to use the reference shot for a custom color balance.

Hope you do not mind but I have had a quick got at re-processing your image to get it close using this technique (and got rid of the vignetting with a synthetic flat)...

i am very interested in the synthetic flats as i am having problems with vignetting

Originally Posted by Terry B

Open the pic in Iris, define a small area of blank sky, type "black" and magically it is gone.
I get the same problem with the moon.
A nice demonstration of the same problem is at http://astro.ai-software.com/article...dslr_iris.html

wow cheers , had a lookk at this and it looks the same colour as my images