Another M8 and M20 learning to use updated gear

rcheshire (Rowland) · #1 13-09-2015, 11:03 AM

First time posting for a long time.

This is a trial using a new imaging setup for the first time. Another learning curve as I refine acquisition settings and discover the gotchas with the new equipment. Won't bore you with the details.

A modified Canon 1000D with regulated cooling (-5C last night) - unguided wide field - tracking was good...

37 lights x 120secs iso1600 (at f4.2 iso800 might be better?) under outer suburban skies. Unfortunately, cloud rolled in about 11pm.

Bias and flats - exsfos' light box did an excellent job of the flats.

No darks due to cooling - there is no discernible difference between bias and dark frames at -5C. The bias frames substitute for darks for light frame calibration and flat calibration. Without cooling I usually subtract the bias from the flats only. Leaving the dark untouched to be subtracted from the light frames. Unless scaling the darks in PixInsight.

Preprocessing with my rawprepro script, followed by deBayer align and stack in Pixinsight. Post processing in StarTools. Didn't go to a lot trouble with detail. The stars are pretty much all white and should show more colour in this region.

Lots wrong with this image - bloated stars, camera was slightly off-axis - stars out of round on the left side in particular.

Atmos (Colin) · #2 13-09-2015, 12:09 PM

Still a nice looking image, something I would be more than happy with myself

raymo · #3 13-09-2015, 02:14 PM

Looks pretty good to me Rowland. If you are looking for comment, the only thing that catches my eye is that the cores of both 8 and 20 are blown out.
raymo

rcheshire (Rowland) · #4 13-09-2015, 05:01 PM

Quite right Ray. Need to slow it down or shorten the subs. Two elements plus flattner, compared to the 13 element 200mm prime lens. Lots more light.

Camelopardalis (Dunk) · #5 13-09-2015, 06:28 PM

That's some good bright data Rowland

since you have Pixinsight anyway, you could dial the cores back a bit with a little HDRMultiscale Transform. Experiment with 6 or 7 layers as a starting point, see what you think.

rcheshire (Rowland) · #6 13-09-2015, 06:54 PM

Thanks Dunk. I would have spent more time on it, except for the blown out stars and other acquisition faults. A scan around the edges of the image tells the tale.

EDIT: uploaded a screen shot of the 14mb tiff file converted to jpeg. The first image was badly compressed and very messy. Hopefully this one is a better example of the issues. http://www.iceinspace.com.au/forum/a...e.php?a=187895