Caldwell 7 — Galaxy in Camelopardalis
NGC 2403
About C7
Description
NGC 2403 is a bright spiral galaxy in Camelopardalis, about 8 million light-years away. It is a member of the M81 group and resembles a smaller version of M33, with prominent HII regions and well-defined spiral arms.
Observing Tips
One of the brightest galaxies outside the Messier catalog, visible in binoculars from dark sites as a faint smudge. A 6-inch telescope shows an elongated glow with a brighter core. Larger scopes reveal hints of spiral structure. Best in winter and spring evenings.
History
Discovered by William Herschel on November 1, 1788. In 1954, Allan Sandage used Cepheid variable stars in NGC 2403 to refine the extragalactic distance scale.
Fun Facts
NGC 2403 has produced two observed supernovae: SN 1954J and SN 2004dj. Its giant HII regions rival the Tarantula Nebula in luminosity.
Observe
1Properties
Position & Identifiers
2How easy to spot?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | Easy | Easy | Easy |
| 150 mm Newton 150mm Newt. | Easy | Easy | Easy |
| Celestron C8 (203 mm SCT) C8 203mm | Easy | Easy | Easy |
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: Image Data - Subaru Telescope (NAOJ), Hubble Legacy Archive; Processing - Robert Gendler. License: CC BY 4.0. (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.
