clear sky chart

Job 9:9

Job 9:9-10
9 He is the Maker of the Bear and Orion,
the Pleiades and the constellations of the south.
10 He performs wonders that cannot be fathomed,
miracles that cannot be counted.

Sunday, July 21, 2013

M82 with the CCD

I imaged M82 the other day, when it was rather low in the northern sky.  It was cloudy to the south, where I wanted to image.  Ursa Major was totally in the clear, so I thought I'd give it a try.

I imaged this using Ha for the red channel, and wideband green and blue to fill in the other colors.  The Ha was unaffected by the light pollution, as I was able to easily pick up the starburst region which I have never gotten before. The star spikes are artificially added using Carboni's astro tools.

What is interesting with the CCD is that very little post processing is required after these images are taken.  Very little histogram stretching is required.  The hardest part is combining the colors properly, but the detail appears pretty much as you see it here, after the channels are combined.  With the dslr, I'd have to stretch the histogram massively to get this, and even then, the starburst area does not show up.

I really need to take notes on the next DSO I image and write down the post processing workflow.  You wouldnt believe how simple it is, once the colors are combined and corrected, however, because the color levels are never correct when theyre taken, its difficult to know when they're right. 

To summarize, when Iprocessed this, I combined the colors, got rid of the nasty gradient on the green and blue, because of the light pollution, got the color balance close.  Did some very minor histogram stretching, a little bit of noise reduction.  Reduced the star size... sharpened, and here it is....

This is the unprocessed Ha stack with the only modification being done was to set the black point.  This is a stack of 5 frames.  No noise reduction, no histogram stretching...This is just as you see it coming out of DSS, except the black point was set in photoshop.  This was used as my red channel in the above image.


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