NGC 663
Scientific overview
NGC 663 is an open cluster in the constellation Cassiopeia. It shines at apparent magnitude 7.1 and spans about 6 arcminutes of sky.
Observation guide
Guidance follows standard observing practice, derived from the object's real magnitude and position. A dark, moonless sky always helps.
Location in the sky
Precision measurements
Distances and velocities from SIMBAD · NGC 663
| Distance | 9,622 ly | SIMBAD · catalogued |
| Physical size (major axis) | 16.792883 ly | SIMBAD · derived |
| Radial velocity | -32.3 ± 1.2 km/s | SIMBAD · measured |
| Right ascension (ICRS) | 26.5875 deg | SIMBAD · measured |
| Declination (ICRS) | 61.211667 deg | SIMBAD · measured |
Full field-level provenance
- Distance: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · mesDistance · dist · 2021A&A...651A.104P · distance indicator: paral · catalogued value · source value 2950 pc · retrieved 2026-07-11
- Physical size (major axis): Centre de données astronomiques de Strasbourg (CDS) · derived (OpenNGC angular size × SIMBAD distance) · physical size = angular size × distance (small-angle); angular size from OpenNGC, distance from SIMBAD mesDistance · derived · retrieved 2026-07-11
- Radial velocity: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · rvz_radvel · 2017A&A...600A.106C · direct catalogue measurement · retrieved 2026-07-11
- Right ascension (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · ra · 2020A&A...633A..99C · direct catalogue measurement · retrieved 2026-07-11
- Declination (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · dec · 2020A&A...633A..99C · direct catalogue measurement · retrieved 2026-07-11
Physical size is derived from the OpenNGC angular size and the catalogued distance (small-angle: size = angle × distance). This is a Galactic object: its Doppler shift is shown as a radial velocity, not a cosmological redshift. Fields a source did not provide are omitted, never invented.
Other objects in Cassiopeia
| Object | Type | Mag | Size (′) |
|---|---|---|---|
| Owl ClusterC 13 · NGC 457 | Open cluster | 6.4 | 7.8 |
| IC 1805 | Cluster with nebulosity | 6.5 | 60 |
| IC 1848 | Cluster with nebulosity | 6.5 | 40 |
| NGC 129NGC 129 | Open cluster | 6.5 | 5.4 |
| NGC 654NGC 654 | Open cluster | 6.5 | 6.3 |
| NGC 1027NGC 1027 | Open cluster | 6.7 | 7.8 |
| NGC 7789NGC 7789 | Open cluster | 6.7 | 14.4 |
| M 52M 52 · NGC 7654 | Open cluster | 6.9 | 9.9 |
Sources
The primary and reference sources this topic draws on.
- OpenNGCOpenNGC (M. Verga) — NGC/IC, Messier, and Caldwell catalogue data
Openly-licensed deep-sky catalogue: object types, positions, magnitudes, sizes, morphology, and cross-identifiers.