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M101 Widefield (HaRGB)

Technical card

Resolution: 4911x3954

Dates: Feb. 6, 2015

Astrodon Blue: 44x180" -25C bin 1x1
Astrodon Green: 35x180" -25C bin 1x1
Astrodon Ha 3nm: 30x1390" -25C bin 1x1
Astrodon Red: 31x180" -25C bin 1x1

Integration: 17.1 hours

Flats: ~30

Bias: ~200

Avg. Moon age: 16.58 days

Avg. Moon phase: 96.34%

Temperature: -25.00 job: 544705

RA center: 211.059 degrees

DEC center: 54.637 degrees

Orientation: -179.999 degrees

Field radius: 0.840 degrees

Locations: The Hills Observatory, Manchester, United Kingdom


Taken over 6 nights from 27 Dec 2014 to 6 Feb 2015. Made using Ha and separate R, G, & B filters.

NGC 5477 is a small galaxy to the left of M101, but if you look all over the image you will find many more galaxies especially in the top left. This image is the full size of the frame. I have also posted a closer crop of M101. All processing is done in PixInsight.

The Ha exposures were of different lengths, 600, 900, 1200 & 1800s.

I never thought I would be able to take RGB images from my home in light polluted Manchester UK. I believe this is only possible due to the Astrodon filters I use which has a slight gap between the green and red. The subs I have used here are just 180s but I know I can go up to about 8min which I will be doing from now on.

Note: I uploaded the wrong version, the second version has a slightly warmer hue.



Mike Oates


Sky plot

Sky plot


M101 Widefield (HaRGB), Mike Oates