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AsteriaStar
Globular cluster · Ophiuchus

M 12

Deep skyM 12NGC 6218

Scientific overview

M 12 is a globular cluster in the constellation Ophiuchus. It shines at apparent magnitude 6.07 and spans about 11.1 arcminutes of sky.

Observation guide

Difficulty
Binoculars
Recommended equipment
10×50 binoculars or any small telescope
Best observed
Summer (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
Ophiuchus
RA / Dec
16.7874h / -1.9478°
Hemisphere
Both
Season
Summer

Precision measurements

Distances and velocities from SIMBAD · M 12

Distance16,308 lySIMBAD · catalogued
Physical size (major axis)52.65565 lySIMBAD · derived
Radial velocity-41.2 ± 0.2 km/sSIMBAD · measured
Right ascension (ICRS)251.809083 degSIMBAD · measured
Declination (ICRS)-1.948528 degSIMBAD · measured
Full field-level provenance
  • Distance: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · mesDistance · dist · 2008MNRAS.389.1924F · catalogued value · source value 0.005 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.

ObjectTypeMagSize (′)
IC 4665Open cluster4.224.6
NGC 6633NGC 6633Open cluster4.612
M 10M 10 · NGC 6254Globular cluster4.989.3
rho Oph NebulaNebula5.160
M 19M 19 · NGC 6273Globular cluster5.577.5
M 14M 14 · NGC 6402Globular cluster5.739.9
NGC 6235NGC 6235Globular cluster7.24.2
M 62M 62 · NGC 6266Globular cluster7.397.8

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.