Messier 81 and 82, combining previous image sets.
This is a combination of 26 subs, one set from April 2020, of 10 x 10 minutes duration and another set of 16 x 5 minutes duration from 2018. All at ISO400. Taken with my 480mm f/6 refractor on a modified Canon 80D.
Technical card for 2020 session is in my Backyard Astrophotography Album.
I’ve not cropped this, so some background galaxies can be seen in the corners.
M81 is a large spiral galaxy in Ursa Major that is reasonably local to us at 12 million light years. Its companion, M82 has been disrupted by an encounter with M81 in the past.
M82 is a starburst galaxy with intense star formation triggered by the gravitational influence of M81. The red fan-like filaments at right angles to the axis of the galaxy are formed by a "superwind". The intense star formation has resulted in multiple supernovae explosions occurring about once every 10 years - the explosions power the super wind. The filaments are expanding outwards at about 600 miles a second and glow brightly in hydrogen alpha (red). They are also a very strong source of radio emission, listed as 3C 231 in the 3rd Cambridge catalogue of radio sources.
NGC3077 lies top left. It’s classified as a peculiar galaxy and may have interacted with M81 in the past and become disrupted. Some radial dust bands are just visible in this image - couldn’t see this detail before so nice to pick up in this longer integration.
The faint galaxy Holmberg IX lies just above M81, seen here as a faint triangular smudge contained in a trapezoid set of stars. It seems to be a companion dwarf galaxy to M81, a bit like our Magellanic Clouds.
The small galaxies bottom left and right are PGC28563 and PGC28225 respectively.
Image scale: 1.59 arcsecond/pixel
Field-of-view: 1d 37' 34.0" x 1d 9' 3.6"
Image centred on:
RA: 9hr 55min 25.931s
DEC: +67d 10min 05.69s
I tried a few new things in PixInsight processing to try and get the best integrated image. I used a custom expression in SubFrame Selector and graded all the subs based on that expression (using Eccentricity, SNR and FWHM). The integration then used the weighted images (via a FITS keyword) so that the best made the most contribution and the worst, least.
Messier 81 and 82, combining previous image sets.
This is a combination of 26 subs, one set from April 2020, of 10 x 10 minutes duration and another set of 16 x 5 minutes duration from 2018. All at ISO400. Taken with my 480mm f/6 refractor on a modified Canon 80D.
Technical card for 2020 session is in my Backyard Astrophotography Album.
I’ve not cropped this, so some background galaxies can be seen in the corners.
M81 is a large spiral galaxy in Ursa Major that is reasonably local to us at 12 million light years. Its companion, M82 has been disrupted by an encounter with M81 in the past.
M82 is a starburst galaxy with intense star formation triggered by the gravitational influence of M81. The red fan-like filaments at right angles to the axis of the galaxy are formed by a "superwind". The intense star formation has resulted in multiple supernovae explosions occurring about once every 10 years - the explosions power the super wind. The filaments are expanding outwards at about 600 miles a second and glow brightly in hydrogen alpha (red). They are also a very strong source of radio emission, listed as 3C 231 in the 3rd Cambridge catalogue of radio sources.
NGC3077 lies top left. It’s classified as a peculiar galaxy and may have interacted with M81 in the past and become disrupted. Some radial dust bands are just visible in this image - couldn’t see this detail before so nice to pick up in this longer integration.
The faint galaxy Holmberg IX lies just above M81, seen here as a faint triangular smudge contained in a trapezoid set of stars. It seems to be a companion dwarf galaxy to M81, a bit like our Magellanic Clouds.
The small galaxies bottom left and right are PGC28563 and PGC28225 respectively.
Image scale: 1.59 arcsecond/pixel
Field-of-view: 1d 37' 34.0" x 1d 9' 3.6"
Image centred on:
RA: 9hr 55min 25.931s
DEC: +67d 10min 05.69s
I tried a few new things in PixInsight processing to try and get the best integrated image. I used a custom expression in SubFrame Selector and graded all the subs based on that expression (using Eccentricity, SNR and FWHM). The integration then used the weighted images (via a FITS keyword) so that the best made the most contribution and the worst, least.