IC 4651
Scientific overview
IC 4651 is an open cluster in the constellation Ara. It shines at apparent magnitude 6.9 and spans about 9.6 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 · IC 4651
| Distance | 3,196 ly | SIMBAD · catalogued |
| Physical size (major axis) | 8.925844 ly | SIMBAD · derived |
| Radial velocity | -30.51 ± 0.08 km/s | SIMBAD · measured |
| Right ascension (ICRS) | 261.212083 deg | SIMBAD · measured |
| Declination (ICRS) | -49.916944 deg | SIMBAD · measured |
Full field-level provenance
- Distance: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · mesDistance · dist · 2022MNRAS.509..421N · distance indicator: paral · catalogued value · source value 0.98 kpc · 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 · 2021A&A...647A..19T · direct catalogue measurement · retrieved 2026-07-11
- Right ascension (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · ra · 2021A&A...647A..19T · direct catalogue measurement · retrieved 2026-07-11
- Declination (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · dec · 2021A&A...647A..19T · 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 Ara
| Object | Type | Mag | Size (′) |
|---|---|---|---|
| NGC 6397C 86 · NGC 6397 | Globular cluster | 5.17 | 15.3 |
| NGC 6250NGC 6250 | Cluster with nebulosity | 5.9 | 9.6 |
| NGC 6208NGC 6208 | Open cluster | 7.2 | 8.4 |
| NGC 6200NGC 6200 | Open cluster | 7.4 | 8.1 |
| NGC 6204NGC 6204 | Open cluster | 8.2 | 4.5 |
| NGC 6362NGC 6362 | Globular cluster | 8.86 | 8.4 |
| NGC 6352C 81 · NGC 6352 | Globular cluster | 8.87 | 7.2 |
| NGC 6193C 82 · NGC 6193 | Open cluster | — | 8.1 |
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.