Globular Cluster · Ophiucus

M107 NGC 6171

Magnitude
7.9
Season
Summer
Difficulty
Hard
Star-hop chart
M1070.0° field0° rotation
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Imaging reference
NGC 6171 (M107) Globular Cluster

Observer's guide

About NGC 6171

NGC 6171 (M107) is catalogued as a globular cluster in Ophiucus. Its J2000 position is RA 16:32:31.92, Dec -13:03:13.1, corresponding to 248.1327 degrees RA and -13.0538 degrees Dec. The local catalogue places it about 19,600 light-years away. Its referenced angular extent is approximately 10 by 10 arcminutes.

Observing tips

StarWatchr rates this as a hard target at magnitude 7.9. It is associated with summer observing, with midnight placement typically strongest around May. From 52 degrees north its theoretical meridian altitude is about 24.9 degrees; local horizons and the live altitude chart determine the practical window.

A small telescope under reasonably dark skies is a good starting point; use the live altitude chart to choose its highest point.

What to expect

The SIMBAD classification for the matched source is GlC. A published radial velocity value is -34.7 km/s. The SIMBAD record currently connects it to 843 bibliographic references.

At roughly 10 arcminutes across, it benefits from a narrower field and adequate image scale. Use the listed 10 by 10 arcminute extent to check framing, and treat catalogue magnitude as integrated brightness rather than a direct measure of visual contrast.

Sourced catalogue data

Scientific record

Measurements for M107 are kept separate from practical observing guidance.

Coordinates (J2000/ICRS)
RA 248.13275° · Dec -13.053778°
SIMBAD classification
GlC
Angular extent
10′ × 10′
Position angle
90°
Radial velocity
-34.7 km/s
Redshift
-0.00011574
Linked bibliography
843 references
Best midnight placement
May
Observable latitude range
-90° to 76.9°

Source: SIMBAD astronomical database (CDS, Strasbourg) (ODbL; checked 2026-08-09). Catalogue values may change when new measurements are published.

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24-hour altitude profile

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