NGC 2527 (also NGC 2520, Cr 174, OCl 685, ESO 430-SC015, Lund 429, and GC 1621) is a magnitude +6.5 open star cluster located 1960 light-years away in the constellation Puppis.
The cluster was discovered by German-British astronomer William Herschel using a 47.5 cm (18.7 inch) f/13 speculum reflector at Datchet, Berkshire, on the 9th December 1784. The cluster was rediscovered by John Herschel in 1837 and relisted as NGC 2520.
NGC 2527 is relatively scattered with an apparent diameter of about 20'. Its distance is estimated at ~601 parsecs (~1960 light-years) away located in the Orion Arm, a short distance from the Gum Nebula. Its main stars are of ninth magnitude, and around thirty stars down the twelfth magnitude can be counted stars. The arrangement of the components vaguely resembles a trapezoid, dominated in the north-east by a star of magnitude 8.5. The age of the cluster is estimated to be around 445 million years. Its hottest stars are of spectral class A2-A8 and there are some red giants, a sign that the turnoff in the colour-magnitude diagram is below the spectral class O and B, ie there are no blue stars. The cluster can be observed 4 degrees to the SW of the star Rho Puppis, in the direction of a very rich starfield of background stars. It shows as misty smudge dominated by two stars of magnitude 8 with 10x50 binoculars. A telescope of 80mm aperture will completely resolve most of its stellar components; larger instruments and higher magnifications do not add additional components beyond magnitude 12 (beyond the background stars). . The declination of this cluster favours observers in the Southern Hemisphere, and is circumpolar from very southerly latitudes. The best time to observe is in the evening sky is between December and April.
Right Ascension 08h 04m 58.2s, Declination -28° 08' 48"
