Caldwell 23 — Galaxy in Andromeda
NGC 891
About C23
Description
NGC 891 is a spectacular edge-on spiral galaxy in Andromeda, about 30 million light-years away. It is considered one of the best examples of an edge-on galaxy, with a prominent dark dust lane bisecting its disk, giving us a cross-sectional view of a Milky Way-like galaxy.
Observing Tips
Visible as a thin, elongated streak in an 8-inch telescope. The dust lane requires at least a 10-inch scope and good conditions. Low to medium power works best for the 13-arcminute length. Best observed in autumn and winter evenings.
History
Discovered by William Herschel on October 6, 1784. NGC 891 is often compared to our Milky Way because of its similar size, luminosity, and morphological type (Sb spiral).
Fun Facts
Deep images reveal a complex system of dust filaments extending above and below the galaxy's disk plane, likely blown out by supernova explosions. NGC 891 is considered the best analog of how our Milky Way would look from the outside, viewed edge-on.
Observe
1Properties
Position & Identifiers
2How easy to spot?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | Hard+ | Hard | Hard |
| 150 mm Newton 150mm Newt. | Medium | Medium | Hard+ |
| Celestron C8 (203 mm SCT) C8 203mm | Medium | Medium | Medium |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
3Visibility
Set a location in User Settings to see visibility data.
4
Eyepiece View
5
Best Magnification
Explore
6
Surface Brightness
7
Morphology Decoder
8
Inclination & True Shape
9
Redshift
10
Size Comparator
Discover
11
Light Travel Time Machine
12
Relativistic Travel
Community Photos (1)
Credit: Hewholooks. License: CC BY-SA 3.0. (Wikimedia Commons)
Skybred Mar 2, 2026
Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
Visibility scores assume a 150 mm Newton at Bortle 4.
Explore Nightbase
Related knowledge, tools, and stories — no observation planning required.
