M101 with ASI071MC-cool

ndb

Another quick test, exposure of only 36 minutes.

M101 is a very pale galaxy and requires a very dark sky. This image was taken with a strong light pollution.

The greenish color is due to the hard processing to get rid of light pollution.

The image also contains numerous, faint, elliptical, spiral, and irregular galaxies.

Newton 150mm / 6 inches.

Note that the image is slightly cropped because my GPU coma corrector corrects coma but adds astigmatism at left and top of the full image. The collimation was pretty good and the APS-C format sensor ought to stand in the fullly-corrected field. Obviously the corrector must have a problem such as tilting or decentering. This is not due to the camera.

Nicolas

m101_2017-03-26_n150_asi071mcc_73x30s_2k.jpg

moonprince

it is very sharp stars. nice shot.

h2opolo

I've been imaging that as well with pretty much the same results. How many frames are you getting? I stacked about 2 hours worth and got a lot more detail and saturation.

aferrari66

May I ask some details about the exposure/time/settings? New to the camera and getting ready to experiment. Was your shot a single 36min exposure-guided? What was your integration time/number of stacks?

Did you take dark frames? Flats? Bias?

ndb

Technical data were mentionned in the file name: 73 x 30s (that's a very quick shot!). No flat, no bias, no offset. Noise mainly come from my hard processing to unveil the arms drowned in light pollution. The camera is desserviced by light pollution. Fortunately, the 14-bit ADC greatly helps to distinguish the real signal of the galaxy in the bright background. Results could be stunning from countryside.

Nicolas