Globular Cluster NGC 6749

NGC 6749
NGC 6749: Section of DSS2 [147]

History

This cluster of stars was discovered by John Herschel on 15th 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, © 2022 Dr. Wolfgang Steinicke [277]
Designation NGC 6749
Type GCL
Right Ascension (J2000.0) 19h 05m 15.3s
Declination (J2000.0) +01° 54' 05"
Diameter 4 arcmin
Visual magnitude 12.4 mag
Metric Distance 7.900 kpc
Dreyer Description Cl, L, lC, st L & S
Identification, Remarks h 2029; GC 4466; GCL 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 June to September.

Finder Chart Globular Cluster NGC 6749
Globular Cluster NGC 6749 in constellation Aquila. Charts created using SkySafari 6 Pro and STScI Digitized Sky Survey. Limiting magnitudes: Constellation chart ~6.5 mag, DSS2 close-ups ~20 mag. [149, 160]

Objects Within a Radius of 10°

References

  • [147] Aladin Lite; aladin.unistra.fr/AladinLite
  • [149] SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
  • [160] The 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; jstor.org/stable/108864
  • [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