Reprocessed M20 - M8 - M17

[bluescope]

I hope these images look better this time around.

:thumbsup:

[little col]

really like them steve :eyepop:

[bluescope]

Cheers Col !

:thumbsup:

[jase]

Steve, Are you subtracting any flats on these images? The fields look vignetted. Also take a look at the histogram info on each of the images - you're severly black clipped data, thus losing a lot of valuable information (see attachment).

[bluescope]

No flats Jase only just started to do stacking and am only doing dark frames at present. I don't quite understand the flat side of things yet. It's all a big learning process. Thanks for the screen capture although I haven't really studied it as yet. I appreciate your comments.

:thumbsup:

[little col]

thats interesting jase , how is the data black clipped to much and where on the attachment does this show?
i am using cs2 myself but am still learning its curves and histrograms
col

[jase]

Col, if you look at the histogram data you will note that the black point (far left) does not start at 0 (or close too). Instead it starts very high indicating more data could be stretched from the image or it has been clipped by another processing routine.
When working with levels and curves - always set your levels white point first, then start working with curves. Finally, don't make huge changes to your black point until close to the end of your processing routine.

The web has loads of information on histograms. Understanding how they work is critical if you want good results. They are also a good tool for evaluating your data. Here's one website of many available - http://www.larry-bolch.com/histogram/ The first example show black clipping. Hope this helps.

[little col]

that really helps jase thanks very much i will have a good read of this now as i understand that it is a vital part of image processing and if i can get into the histrogram now it should become second nature in future processing :thumbsup:
many thanks col

[Garyh]

Other than the clipping you have done a nice job of them!!
Nice sharp focus as well!!
keepem coming!!!

[bluescope]

Thanks Gary, as I said it's all a learning process and you have to start somewhere ay !

:thumbsup: