< Messier Index
Messier 55
Observation data (w:J2000 epoch)
Class XI
Constellation Sagittarius
Right ascension 19h 39m 59.40s[1]
Declination -30° 57′ 43.5″[1]
Distance 17.3 kly[citation needed] (5.3 kpc)
Apparent magnitude (V) +7.42[1]
Apparent dimensions (V) 19′.0
Physical characteristics
Mass kg ( M)
Radius 48 ly[2]
Other designations M55, NGC 6809, GCl 113[1]

Messier 55 (also known as M55 or NGC 6809) is a w:globular cluster in the w:constellation Sagittarius. It was discovered by w:Nicolas Louis de Lacaille in w:1751 and catalogued by w:Charles Messier in w:1778. M55 is at a distance of about 17,300 w:light-years away from w:Earth. Only about half a dozen w:variable stars have been discovered in M55.

References

  1. 1 2 3 4 "SIMBAD Astronomical Database". Results for NGC 6809. http://simbad.u-strasbg.fr/Simbad. Retrieved 2006-11-16.
  2. ↑ distance × sin( diameter_angle / 2 ) = 48 ly. radius
 
Messier Index
M1 • M2 • M3 • M4 • M5 • M6 • M7 • M8 • M9 • M10 • M11 • M12 • M13 • M14 • M15 • M16 • M17 • M18 • M19 • M20 • M21 • M22 • M23 • M24 • M25 • M26 • M27 • M28 • M29 • M30 • M31 • M32 • M33 • M34 • M35 • M36 • M37 • M38 • M39 • M40 • M41 • M42 • M43 • M44 • M45 • M46 • M47 • M48 • M49 • M50 • M51 • M52 • M53 • M54 • M55 • M56 • M57 • M58 • M59 • M60 • M61 • M62 • M63 • M64 • M65 • M66 • M67 • M68 • M69 • M70 • M71 • M72 • M73 • M74 • M75 • M76 • M77 • M78 • M79 • M80 • M81 • M82 • M83 • M84 • M85 • M86 • M87 • M88 • M89 • M90 • M91 • M92 • M93 • M94 • M95 • M96 • M97 • M98 • M99 • M100 • M101 • M102 • M103 • M104 • M105 • M106 • M107 • M108 • M109 • M110
This article is issued from Wikibooks. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.