NGC 6544

This article needs additional citations for verification. Please help by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources:  –  ·  ·  · scholar · JSTOR (December 2016) (Learn how and when to remove this template message)

NGC 6544
Observation data (J2000 epoch)
Constellation	Sagittarius
Right ascension	18h 07m 21s
Declination	−24° 59′ 50″
Distance	9450 light years
Apparent magnitude (V)	9
Apparent dimensions (V)	1'
Physical characteristics
Other designations	Cr 366, GCl 87[1]
See also: Globular cluster, List of globular clusters

NGC 6544 is a small globular cluster visible in the constellation Sagittarius. It is magnitude 7.5, diameter 1 arcminute. It is less than 1 degree southeast of Messier 8, the Lagoon Nebula.

Observation[]

Map to find NGC 6544

NGC 6544 is located in the western part of the constellation, on the edge of a rich star field; its location is easily recoverable as it is located just 50' towards the southeast compared to the famous Lagoon Nebula. It can also be noted with a binoculars 10×50mm as a small white spot like a misty star; with a telescope 120mm and 100× magnification around you may notice a few tiny little star, but overall the clutter is almost unsolvable. Telescopes from 200mm up and high magnification allow resolving of dozens of dim stars.

Because its declination is rather southern, this cluster can be mainly observed by observers located in southern hemisphere, although it is still observable fairly even up to medium temperate latitudes. The best time for observation in the evening sky is the one included between June and October.

History of observations[]

NGC 6544 was observed for the first time by William Herschel in 1784,^[2] who watched through his 18.4 inch reflector; he described it as a fairly bright and large object, circular and resolvable into stars; in New General Catalogue provides a similar description.

Characteristics[]

NGC 6544 is a globular cluster of medium density, estimated value of 5 on a scale between 1 and 12^{[clarification needed]}. Its distance is estimated at 2900 parsecs (9450 light years) from the Sun, which in its position corresponds to a distance of 6100 parsecs from the center of the Milky Way and only 100 parsecs from the galactic plane, making it one of the closest globular clusters to known galactic plane known. Its small angular size, equal to just under 4' for the main body volume and corresponding to just 3.2 parsecs, makes it also one of the smaller globular clusters known.

NGC 6544 has a prograde orbit around the Milky Way, but its orbit is otherwise unusual, and has a high proper motion. It is unclear whether it formed with the Milky Way or came from elsewhere. In 2021, a low-luminosity globular cluster, named VVV-CL160, was discovered with a similar location, metallicity, and trajectory. It may be associated with NGC 6544.^[3]

In 1999 a millisecond pulsar in a binary system was discovered within the cluster and cataloged as PSR J1807-2459. There are a few notable variable stars that part of NGC 6544; a 1993 study focused on the region around NGC 6544 has identified some variable stars, of which only one is found to belong in storage: it is a RR Lyrae variable with a period of 0.57 days.

Note[]

References[]

• Tirion, Rappaport, Lovi, Uranometria 2000.0, William-Bell inc. ISBN 0-943396-15-8
• Robert Burnham, Jr, Burnham's Celestial Handbook: An observer's guide to the universe beyond the solar system, vol 3, p.1556

External links[]

Wikimedia Commons has media related to NGC 6544.

• NGC 6544

This star cluster–related article is a stub. You can help Wikipedia by .

• v
• t