The Hyades is a very large loose naked eye open cluster located in the constellation of Taurus. It spans 5.5 degrees of sky, which is equivalent to 11 times the diameter of the full Moon. At a distance of 153 light-years this is the nearest open cluster - the Ursa Major Moving Group is closer, but's extremely scattered and more of a cluster like object than a true cluster. Consequently, the Hyades is one of the top studied open clusters of all.
The Hyades is easily found as it circles the brightest star in Taurus, first magnitude orange giant star Aldebaran (α Tau - mag. +0.87). It's not unreasonable to assume that Aldebaran is also a member of the Hyades. However, it's purely a foreground star, an interloper located only 65 light-years distant that happens to be in the same line of sight. As a naked-eye object, the Hyades have been known since prehistoric times.
The cluster is best seen from northern latitudes during the months of November, December and January.
To the naked eye, at least 20 stars can be seen arranged in a "V" construction with the number rising to above 100 with good quality binoculars. This package of stars displays many nice colours, including several fine double stars. Due to its large apparent size, this is a perfect binocular cluster. The brightest component stars are theta2 Tauri (θ2 Tau - mag. +3.4), epsilon Tauri (ε Tau - mag. +3.5), gamma Tauri (γ - mag. +3.7), delta1 Tauri (δ1 Tau - mag. +3.8) and theta1 Tauri (θ1 Tau - mag. +3.8). In total, it contains at least 200 stars and is estimated to be 625 million years old.
Located 12 degrees northwest of the Hyades is M45, the brilliant Pleiades open cluster.
C41 Data Table
|Object Type||Open Cluster|
|RA (J2000)||04h 26m 54s|
|DEC (J2000)||+15h 52m 00s|
|Apparent Size (arc mins)||330 x 330|
|Age (years)||625 Million|
|Number of Stars||>200|
|Other Names||Collinder 50, Melotte 25|
|Notable Feature||Nearest open cluster to the Solar System|