NGC 891 (AKA Caldwell 23 or Silver Sliver Galaxy) is an edge-on unbarred spiral galaxy, about 30 mly away in the constellation Andromeda. It was discovered by William Herschel on October 6, 1784. The galaxy is a member of the NGC 1023 group of galaxies in the Local Supercluster. It has an H II nucleus.

The object is visible in small to moderate size telescopes as a faint elongated smear of light with a dust lane visible in larger apertures.

In 2005, due to its attractiveness and scientific interest, NGC 891 was selected to be the first light image of the Large Binocular Telescope.

In 2012, it was again used as a first light image of the Lowell Discovery Telescope with the Large Monolithic Imager.

Supernova SN 1986J was discovered on August 21, 1986 at apparent magnitude 14.

NGC 891 looks as the Milky Way would look like when viewed edge-on (some astronomers have even noted how similar to NGC 891 our galaxy looks as seen from the Southern Hemisphere) and, in fact, both galaxies are considered very similar in terms of luminosity and size.

Studies of the dynamics of its molecular hydrogen have also proven the likely presence of a central bar. 

Recent high-resolution images of its dusty disk (including mine) show unusual filamentary patterns. These patterns are extending into the halo of the galaxy, away from its galactic disk. Scientists presume that supernova explosions caused this interstellar dust to be thrown out of the galactic disk toward the halo.

It may also be possible that the light pressure from surrounding stars causes this phenomenon.

The bulge and the disk are surrounded by a flat and thick cocoon-like stellar structure. These are interpreted as the remnant of a satellite galaxy disrupted and in the process of being absorbed by NGC 891. [Source: Wikipedia]

CAPTURE Information:

The image was captured with the iOptron CEM120 mount , the venerable Meade 12"LX200 SCT, and my Atik 383L+ mono CCD at F7.16 (2182mm FL). Image subs were taken through Astronomik's filters Lum, R, G and B.

All subs were done at 1x1 bin, -10C, at 10 minutes each.

IMAGE information -- 2020

Lum (600s): 45 subs (7.50hr) on Nov 15th, 16th and 18th.

Red (600s): 20 subs (3.33hr) on Nov 16th and 18th.

Green(600s): 20 subs (3.33hr) on Nov 15th, 16th and 18th.

Blue (600s): 20 subs (3.33hr) on on Nov 15th and 18th.

Processing was done with PixInsight, following (for the most part) kayronjm's tutorial of Feb. 24th from several years back. Only Lum was used to develop the Luminance image.

R, G and B were collected for the color mix.

North is up (pretty sure, or not), and this is a very slight crop due to the various movement of different subs.

COMMENTS:

I last did this galaxy in 2012. Amazing how time flies.

Overall, I was pleased with the outcome.