Globular Cluster NGC 6749

NGC 6749
NGC 6749: Section of DSS2 [147]

History

This cluster of stars was discovered by John Herschel on 15 July 1827. He cataloged it as h 2029 (GC 4466). He noted: «A cluster of loose small stars of various magnitudes; fills the field.» [466] In his «General Catalogue» appeared in 1864 he described GC 4466 as «Cluster; large; little compressed; stars large & small.» [467] John L. E. Dreyer added it as NGC 6749 in 1888. [313]

The cluster is also known as Berkeley 42 and was first misclassified as open star cluster of classification I3r consisting of «very faint stars». [542]

Physical Properties

NGC 6749 is a loose globular cluster. Its blue horizontal branch indicates that the stars are metal-poor, which is typical for globular clusters. Its distance from the Sun is estimated to 7.3 ± 0.9 kpc. It is a halo globular cluster close to the disc plane. [543]

Revised+Historic NGC/IC, Version 22/9, © Dr. Wolfgang Steinicke [277]
DesignationNGC 6749
TypeGCL
Right Ascension19h 05m 15.3s
Declination+01° 54' 05"
Diameter4 arcmin
Visual magnitude12.4 mag
Metric Distance7.900 kpc
Dreyer DescriptionCl, L, lC, st L & S
Identification, RemarksGCL 107, OCL 91, Berkeley 42, not OCL (I3r)

Finder Chart

The globular cluster NGC 6749 can be found in constellation Aquila. Only 1° 43' towards southeast you can find another globular cluster: NGC 6760. The best time for observation is in the months July through September.

Chart Globular Cluster NGC 6749
Globular Cluster NGC 6749 in constellation Aquila. Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

More Objects Nearby (±15°)

References

147Aladin Lite; aladin.u-strasbg.fr/AladinLite (2020-12-23)
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)
313«A New General Catalogue of Nebulae and Clusters of Stars, being the Catalogue of the late Sir John F.W. Herschel, Bart., revised, corrected, and enlarged» Dreyer, J. L. E. (1888); Memoirs of the Royal Astronomical Society. 49: 1–237; Bibcode:1888MmRAS..49....1D
466«Observations of nebulæ and clusters of stars, made at Slough, with a twenty-feet reflector, between the years 1825 and 1833» John Frederick William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1833, Pages: 359-505; DOI:10.1098/rstl.1833.0021
467«Catalogue of nebulae and clusters of stars» John Frederick William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1864; DOI:10.1098/rstl.1864.0001
542«Classification of open star clusters» Ruprecht, J.; Bulletin of the Astronomical Institute of Czechoslovakia, vol. 17, p.33, 1966; Bibcode:1966BAICz..17...33R
543«NGC 6749: a metal-poor halo globular cluster in a disc field rich in Mira variables» L. Rosino, S. Ortolani, B. Barbuy, E. Bica; Monthly Notices of the Royal Astronomical Society, Volume 289, Issue 3, August 1997, Pages 745–752; DOI:10.1093/mnras/289.3.745