The Walraven system has the unique feature that the magnitude
and the colour indices are given in logarithm of the intensity and not in
units of magnitude as is the practice for all other systems.
It has two filters on the ultraviolet side of the Balmer discontinuity
(U and W) which offers interesting possibilities for the analysis of
early type stars.
Most open clusters observed in this system are in the southern sky.
Some are equatorial objects.
The relations of the Walraven Vw and (V-B) indices (La Silla system)
with V and (B-V) in the UBV system are:
- Vubv = 6.885 - 2.5 [Vw + 0.030 (V-B)]
- (B-V)ubv = 2.571 (V-B) - 1.020 (V-B)**2 + 0.500 (V-B)**3 - 0.01
|V||:||V magnitude (Johnson system)|
|Vw||:||Walraven V magnitude|
|V-B||:||V-B colour index|
|B-U||:||B-U colour index|
|U-W||:||U-W colour index|
|B-L||:||B-L colour index|
|N||:||Number of measurements|
List of clusters
Query the references
Last Update: 17 February 1998