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AsteriaStar
Globular cluster · Capricornus

M 30

Deep skyM 30NGC 7099

Scientific overview

M 30 is a globular cluster in the constellation Capricornus. It shines at apparent magnitude 7.1 and spans about 9 arcminutes of sky.

Observation guide

Difficulty
Small telescope
Recommended equipment
≈ 80–100 mm telescope
Best observed
Summer (S. evening sky)
Best hemisphere
Southern

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
Capricornus
RA / Dec
21.6728h / -23.1791°
Hemisphere
Southern
Season
Summer

Precision measurements

Distances and velocities from SIMBAD · M 30

Distance22,831 lySIMBAD · catalogued
Physical size (major axis)59.771278 lySIMBAD · derived
Radial velocity-185.3 ± 0.1 km/sSIMBAD · measured
Right ascension (ICRS)325.092167 degSIMBAD · measured
Declination (ICRS)-23.179861 degSIMBAD · measured
Full field-level provenance
  • Distance: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · mesDistance · dist · 2008MNRAS.389.1924F · catalogued value · source value 0.007 Mpc · 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 · 2018MNRAS.478.1520B · direct catalogue measurement · retrieved 2026-07-11
  • Right ascension (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · ra · 2010AJ....140.1830G · direct catalogue measurement · retrieved 2026-07-11
  • Declination (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · dec · 2010AJ....140.1830G · 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.

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.