Distance from Earth:
27.3 ± 1.8 Mly
13'.5 × 2'.5
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.
Although this galaxy looks as we think our own galaxy would look like when viewed edge-on, recent high-resolution images of its dusty disk show unusual filamentary.
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.
27 December 2011
Italy - Celado Observatory
Temp = -3°C
Newton 800 "Celado"
Canon 1000D unfiltred
Lights: 19x180 sec @ 800ISO
Darks: 19 sec