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Cluster with nebulosity · Orion

Upper Sword

Deep skyNGC 1981

Scientific overview

Upper Sword is a cluster with nebulosity in the constellation Orion. It shines at apparent magnitude 4.2 and spans about 9 arcminutes of sky.

Observation guide

Difficulty
Naked eye
Recommended equipment
no equipment needed (dark sky helps)
Best observed
Winter (evening sky)
Best hemisphere
Both (equatorial)

Guidance follows standard observing practice, derived from the object's real magnitude and position. A dark, moonless sky always helps.

Location in the sky

Constellation
Orion
RA / Dec
5.586h / -4.4251°
Hemisphere
Both
Season
Winter

Precision measurements

Distances and velocities from SIMBAD · NGC 1981

Distance1,282 lySIMBAD · catalogued
Physical size (major axis)3.35573 lySIMBAD · derived
Radial velocity28.8 ± 0.2 km/sSIMBAD · measured
Right ascension (ICRS)83.847917 degSIMBAD · measured
Declination (ICRS)-4.486111 degSIMBAD · measured
Full field-level provenance
  • Distance: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · mesDistance · dist · 2021MNRAS.503.3279S · catalogued value · source value 0.393 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 · 2020AJ....159..199D · 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.

ObjectTypeMagSize (′)
Lower SwordNGC 1980Cluster with nebulosity2.59.3
Great Orion NebulaM 42 · NGC 1976Cluster with nebulosity490
NGC 1788NGC 1788Reflection nebula5.82
NGC 2169NGC 2169Open cluster5.97.2
NGC 1662NGC 1662Open cluster6.413.8
NGC 2175NGC 2175Cluster with nebulosity6.85.4
NGC 1973NGC 1973Nebula75
NGC 1975NGC 1975Nebula710

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.