Optics/mount : 12″ACF 2.7m AP-Reduzer Alt-5
Camera/filters: Atik 11002 Astrodon LRGB HA5nm
Exposure: 4*12×600 Lum,RGB all 1bin
NGC 891 (also known as Caldwell 23) is an edge-on unbarred spiral galaxy about 30 million light-years 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 1999, the Hubble Space Telescope imaged NGC 891 in infrared.
In 2005, due to its attractiveness and scientific interest, NGC 891 was selected to be the first light image of the Large Binocular Telescope.
Supernova SN 1986J was discovered on August 21, 1986 at apparent magnitude 14