M13 : An Evolution Through Three Attempts

[coxy322]

M13 is a great target, there is so much detail and the two contrasting stars nearby have made this a great early target for a novice like me! The mark of a good M13 seems to be the propeller - as comes up on every thread almost!

Here are three attempts, an evolution in my imaging if you like, now I am a few months into the photography side of Astronomy I thought it'd be good to get some feedback on the progress..! So feel free to comment.

1) - A single frame of ISO 1600 and 30 Sec. Taken at a dark sky site. Processed in GIMP. No guiding, poor polar alignment most likely as could not get higher than 30 seconds before trailing.

2) 25 Frames of mixed exposures (30 - 40 secomds) and mixed ISOs. Taken in my back garden. Just getting to grips with taking many shots of the same target. Again the alignment for scope mount would be poor. No guiding and processed in GIMP after stacking in DSS.

3) Taken this weekend, have collimated the polar scope and can now achieve good subs exposure times. This image is 22x 70s ISO 800 with 22x same Darks, 18x Flats and 22x Bias. I took 30 frames and 8 were trailing.

My first proper attempt at building an image with calibration frames. I also worked on this in RAW, stacked and processed in DSS and then adjsuted in GIMP. How did the vignette move to the outer part of the image? I have uploaded a Flat frame - could you advise if it is ok?

You can see the original in full resolutions on this link:

http://www.flickr.com/photos/astrocox/sets/72157629546008656/with/7276704306/

Ash

[coxy322]

Looking for assistance with that flat guys...!

[Quatermass]

Looks really good astrophotography is a great hobby and so much fun to do. I think those gradients and flats can always be dealt with during the processing stages if there not too bad I don't use gimp always used ps but even with good flats you will get gradients sometimes. However your flat looks a little uneven to my eye.

[Gina]

Looks like there's some vignetting. Do you see vignetting in your lights?

[Jessun]

The flat looks OK to me. I have seen, and I mean done, a lot worse than that.

A gradient remaining may be due to other reasons and not a huge problem.

Nice one!

A one click GradientXterminator for example does this: