Open Cluster · Sagittarius

M18 NGC 6613

Magnitude
7.5
Season
Summer
Difficulty
Moderate
Star-hop chart
M180.0° field0° rotation
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Imaging reference
NGC 6613 (M18) Open Cluster

Observer's guide

About NGC 6613

NGC 6613 (M18) is catalogued as an open cluster in Sagittarius. Its J2000 position is RA 18:19:58.49, Dec -17:06:07.1, corresponding to 274.9875 degrees RA and -17.0883 degrees Dec. The local catalogue places it about 4,900 light-years away. Its referenced angular extent is approximately 5 by 5 arcminutes.

Observing tips

StarWatchr rates this as a moderate target at magnitude 7.5. It is associated with summer observing, with midnight placement typically strongest around June. From 52 degrees north its theoretical meridian altitude is about 20.9 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 OpC. A published radial velocity value is -14 km/s. The SIMBAD record currently connects it to 93 bibliographic references.

At roughly 5 arcminutes across, it benefits from a narrower field and adequate image scale. Use the listed 5 by 5 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 M18 are kept separate from practical observing guidance.

Coordinates (J2000/ICRS)
RA 274.9875° · Dec -17.088333°
SIMBAD classification
OpC
Angular extent
5′ × 5′
Position angle
90°
Radial velocity
-14 km/s
Redshift
-0.0000467
Linked bibliography
93 references
Best midnight placement
June
Observable latitude range
-90° to 72.9°

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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