Contains:NGC 5477, M 101, NGC 5457
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M101 the Pinwheel Galaxy

Technical card

Resolution: 3658x2755

Dates: April 17, 2018

Frames: 212x180"

Integration: 10.6 hours

Avg. Moon age: 1.51 days

Avg. Moon phase: 2.55% job: 2063125

RA center: 210.796 degrees

DEC center: 54.346 degrees

Pixel scale: 0.981 arcsec/pixel

Orientation: 358.069 degrees

Field radius: 0.624 degrees

Locations: my lovely garden, near Vienna, Austria

Data source: Unknown


This picture of M101 was taken at 3 nights, and the 72 sharpest of 212 frames were stacked separately to get the best possible resolution, while the whole data set was used to get the deepest possible signal from my light polluted site.

The giant HII region NGC5471 has 17 arcsec diameter and is easily resolved into several knots, so resolution should be around 2 arcsec in the brighter areas of the picture.

The galaxys core with its redder older stars is darkened by narrow dust lanes, and numerous HII regions pop up in the spiral arms, which are dominated by a young blue star population. Some distant galaxies shine through the apparently massive star island, showing its actually a delicate and flat disk. The arms of M101 are not always round, but broken into segments angled at 120°, thats called Woronzow-Weljaminow structures - found in many galaxies but of unknown origin.

Traces of the very faint eastern arms are visible, and the total diameter is around 26 arcmin, almost matching the full moon.

Pure LRGB with 10" f/4 Lacerta Photonewton and GPU corrector, and Gen.1 ASI1600MMC at zero gain equipped with Astronomik Deepsky Filters.

Picture E is a blinking pic on a 100% crop of the core, demonstrating the effect of PixInsights Deconvolution process on the linear (unstretched) Luminance, using a PSF model sampled by the DynamicPSF module.






annotated version


the core


eastern part with NGC5471 the giant HII region


Deconvolution by PSF on Luminance (linear stage)

Sky plot

Sky plot


M101 the Pinwheel Galaxy,