Attribute Pleiades Hyades
1.Constellation: Taurus Taurus
2.Apparent diameter (minutes of arc) : 110 330
3.Distance: 120 pc 46 pc
4.Tr Type: I 3rn* II 3m
5.N (approximate number of stars in the cluster): 100** --
6.Mag. (visual magnitude): 1.2 0.5
7.Br (apparent "V" mag. of the brightest star): 2.87 3.4
8.Spec (spectral type): B5 A2
9.Age (in millions of years): 78 660
10.RV (radial velocity in kilometres per second): +5km/s +43km/s

  *Tr type (the type of open star cluster)-descriptive type based on the system of R.Y. Trumpler (Lick Observatory Bulletin, 14-154,1930). This is a three-part code that characterises the cluster"s degree of the constellation, the range of brightness of its stars, and the richness, as follows:


Concentration:
I. Detached; strong concentration toward centre.
II. Detached; weak concentration toward centre.
III. Detached; no concentration toward centre.
IV. Not well detached from surrounding star cluster.

Range of brightness:
1 .Small range in brightness.
2 .Moderate range in brightness.
3 .Large range in brightness.

Richness:
p -Poor (less than 50 stars)
m -Moderately rich (50 to 100 stars)
r -Rich (more than 100 stars)

The capital Latin letters E,U,N , used in the table, designate that the star cluster seems- (E) prolonged at projection , (U) asymmetrical or (N) concentrated with a nebulosity.

**This is the approximate number stars in the cluster, according to the counting of G. Lynga from 1983.The most used value for the Pleiades is 250 or 280 stars. Their multitude depends on the diameter of the telescope, used to define the star cluster.