Processing Help

[CosmicOrangutan]

Hi Everyone,

Im still very new to Astrophotography but am starting to get some nice subs of the brighter DSO's using my 130pds. The main struggle at the moment is post processing. Could you have a look at this image of M81 + 82 (Only a quick 20 mins of data to show you guys the issue with no post processing) and give me any advice on how to darken the background without darkening the galaxies and stars? Could you also give me any advice on removing the grainy stripes that run across the images? I have tried to adjust the curves in GIMP photo editing software, this does help but still leaves these grainy stripes in the middle of the image.

And finally how do you bring the colour out of the images once they have been stacked in DSS. The subs im taking have colour starting to show but once they're stacked in DSS it just goes to black and white.

thanks to anyone able to give me some advice

George

[oldpink]

its all a matter of adjusting and balancing the histrogram
take the black point down to darken the background and stretch the histogram to bring out the colour & details

[Kropster]

You can boost the saturation when doing the final processing in DSS (saturation tab).

I find 25% to 30% does the job.

[steppenwolf]

Your image does still contain some colour data and looking at the histogram, it is quite well balanced.

Start by iteratively moving the black side of the histogram towards the centre using 'Levels' - I did this in PS3  with 5 iterations of 10 points. This will darken the whole image but that is not really a problem.

You can then start boosting the saturation, again iteratively using whatever saturation tools you have available.

A final tweak with 'Curves' having pegged the black point by 'Ctrl' and left clicking on the background and you end up with the 'down and dirty' result below but there is still more to do. I would thoroughly recommend that you take some Flat calibration frames and apply them as this will make post-processing so much easier and improve the image considerably:-

[CosmicOrangutan]

lovely stuff, thanks guys! its starting to clear up nicely after the thunderstorms this afternoon so gunna go gather some more photons and try these tips  

[glowingturnip]

are those grainy stripes on the individual subs as well ?  I suspect they might be a DSS stacking artifact ?