| constellation = Ophiuchus
| ra = {{RA|17|37|36.15}}[1]
| dec = {{DEC|–03|14|45.3}}[1]
| dist_ly = {{Convert|30.3|kly|kpc|abbr=on|lk=on}}[4]
| appmag_v = +8.32[1]
| size_v = 11.0′
| mass_msol= {{Val|1.04|e=6}}[4]
| radius_ly= 50 ly[2]
| metal_fe = –1.28[4]
| v_hb =
| age =
| notes =
| names = NGC 6402[1]
}}Messier 14 (also known as M14 or NGC 6402) is a globular cluster of stars in the constellation Ophiuchus. It was discovered by Charles Messier in 1764.
At a distance of about 30,000 light-years, M14 contains several hundred thousand stars. At an apparent magnitude of +7.6 it can be easily observed with binoculars. Medium-sized telescopes will show some hint of the individual stars of which the brightest is of magnitude +14.
The total luminosity of M14 is in the order of 400,000 times that of the Sun corresponding to an absolute magnitude of -9.12. The shape of the cluster is decidedly elongated. M14 is about 100 light-years across.
A total of 70 variable stars are known in M14, many of the W Virginis variety common in globular clusters. In 1938, a nova appeared, although this was not discovered until photographic plates from that time were studied in 1964. It is estimated that the nova reached a maximum brightness of magnitude +9.2, over five times brighter than the brightest 'normal' star in the cluster.
Slightly over 3° southwest of M14 lies the faint globular cluster NGC 6366.
Gallery
References
1. ^1 2 3 {{cite simbad | title=NGC 6402 | accessdate=2006-11-15}}
2. ^distance × sin( diameter_angle / 2 ) = 50 ly radius
3. ^1 2 3 {{citation | display-authors=1 | last1=Boyles | first1=J. | last2=Lorimer | first2=D. R. | last3=Turk | first3=P. J. | last4=Mnatsakanov | first4=R. | last5=Lynch | first5=R. S. | last6=Ransom | first6=S. M. | last7=Freire | first7=P. C. | last8=Belczynski | first8=K. | title=Young Radio Pulsars in Galactic Globular Clusters | journal=The Astrophysical Journal | volume=742 | issue=1 | page=51 |date=November 2011 | doi=10.1088/0004-637X/742/1/51 | bibcode=2011ApJ...742...51B | postscript=. |arxiv = 1108.4402 }}