C10
NGC 663
Object Data
- Catalog Designation
- C10
- Type
- OpenCluster
- Constellation
- Cassiopeia
- Magnitude
- 7.1
- Right Ascension
- 01h 42m 36.0s
- Declination
- +61° 15' 00.0"
- Distance
- 6,800 light-years
- Angular Size
- 16
Survey Image
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About C10
Description
NGC 663 is a bright, rich open cluster in Cassiopeia, about 6,850 light-years away. It contains over 400 stars spread across 16 arcminutes, with many hot blue B-type stars and several red supergiants.
Observing Tips
An easy and rewarding target, visible in binoculars as a hazy patch and stunning in small telescopes. A 4-inch scope at 50-80x reveals dozens of stars. Circumpolar from northern latitudes, best placed in autumn.
History
Discovered in 1654 by Giovanni Battista Hodierna. Independently found by William Herschel in 1787. One of the finest open clusters in Cassiopeia.
Fun Facts
NGC 663 is only about 20-25 million years old. It contains an unusual number of Be stars — rapidly rotating hot stars with circumstellar disks — making it ideal for studying this phenomenon.
Community Photos (1)
Credit: Hewholooks. License: CC BY-SA 3.0. (Wikimedia Commons)
Skybred Mar 2, 2026