NGC 6366

NGC 6366 is a globular cluster located in the constellation Ophiuchus. It was discovered by William Herschel on April 12, 1784. The cluster is relatively faint and sparsely populated compared to other globular clusters.

Properties:

• Right Ascension: 17h 27m 44.3s
• Declination: -05° 04′ 33″
• Distance: Approximately 11,700 light-years from Earth
• Diameter: Roughly 80 light-years
• Metallicity: Relatively metal-rich for a globular cluster

Characteristics:

NGC 6366 is considered a low-density globular cluster, belonging to the Oosterhoff type II (OoII) group. This means it has a lower population of RR Lyrae variable stars with shorter periods compared to Oosterhoff type I (OoI) clusters. Its relatively high metallicity suggests it formed from gas that was already enriched with heavier elements from previous generations of stars. Its location in the outer galactic halo could indicate that it was captured by the Milky Way's gravity long ago. The cluster appears rather diffuse in telescopic views, owing to its low stellar density.

Observation:

Due to its faintness, NGC 6366 is best observed with larger telescopes under dark sky conditions. It appears as a hazy, unresolved patch of light.