NGC 1817
Scientific overview
NGC 1817 is an open cluster in the constellation Taurus. It shines at apparent magnitude 7.7 and spans about 9.3 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 1817
| Distance | 5,414 ly | SIMBAD · catalogued |
| Physical size (major axis) | 14.646809 ly | SIMBAD · derived |
| Radial velocity | 66.21 ± 0.04 km/s | SIMBAD · measured |
| Right ascension (ICRS) | 78.139167 deg | SIMBAD · measured |
| Declination (ICRS) | 16.696111 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 1.66 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 · 2019A&A...623A..80C · 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 Taurus
| Object | Type | Mag | Size (′) |
|---|---|---|---|
| NGC 1746NGC 1746 | Open cluster | 6.1 | 18 |
| NGC 1647NGC 1647 | Open cluster | 6.4 | 27 |
| NGC 1807NGC 1807 | Open cluster | 7 | 5.4 |
| Crab NebulaM 1 · NGC 1952 | Supernova remnant | 8.4 | 8 |
| Hind's NebulaNGC 1555 | Reflection nebula | 9.98 | 1.82 |
| Barnard's Merope Nebula | Reflection nebula | — | 25.7 |
| Maia NebulaNGC 1432 | H II region | — | 60 |
| Merope NebulaNGC 1435 | Nebula | — | 30 |
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.