Great Orion Nebula
M 42
Scientific overview
Great Orion Nebula is a cluster with nebulosity in the constellation Orion. It shines at apparent magnitude 4 and spans about 90 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 · M 42
| Distance | 1,592 ly | SIMBAD · catalogued |
| Physical size (major axis) | 41.66912 ly | SIMBAD · derived |
| Physical size (minor axis) | 27.779413 ly | SIMBAD · derived |
| Radial velocity | 27.8 ± 5 km/s | SIMBAD · measured |
| Right ascension (ICRS) | 83.8201 deg | SIMBAD · measured |
| Declination (ICRS) | -5.3876 deg | SIMBAD · measured |
Full field-level provenance
- Distance: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · mesDistance · dist · 2017AstBu..72..257L · catalogued value · source value 488 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
- Physical size (minor 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 · 2022A&A...661A..38P · direct catalogue measurement · retrieved 2026-07-11
- Declination (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · dec · 2022A&A...661A..38P · 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 Orion
| Object | Type | Mag | Size (′) |
|---|---|---|---|
| Lower SwordNGC 1980 | Cluster with nebulosity | 2.5 | 9.3 |
| Upper SwordNGC 1981 | Cluster with nebulosity | 4.2 | 9 |
| NGC 1788NGC 1788 | Reflection nebula | 5.8 | 2 |
| NGC 2169NGC 2169 | Open cluster | 5.9 | 7.2 |
| NGC 1662NGC 1662 | Open cluster | 6.4 | 13.8 |
| NGC 2175NGC 2175 | Cluster with nebulosity | 6.8 | 5.4 |
| NGC 1973NGC 1973 | Nebula | 7 | 5 |
| NGC 1975NGC 1975 | Nebula | 7 | 10 |
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.