Datatype: Geneva parameters

This datatype refers to the Geneva seven-colour parameters V, U-B,B-V,U-B1,B2-V1,d,delta,m2,g. The parameters are linear combination of colour indices that are designed to be independant of interstellar reddening, like the Q parameter of the UBV system. The parameter definitions are:

d = (U - B1) - 1.430 (B1 - B2)
delta = (U - B2) - 0.832 (B2 - G)
g = (B1 - B2) - 1.357 (V1 - G)
m2 = (B1 - B2) -0.457 (B2 -V1)

The usual Geneva colours are stored under the datatype Geneva colours.

The main body of the Geneva data is formed by a systematic observations of open clusters closer than 500 pc and of a few other selected clusters. Some stars have a rather high weight because they have been observed more intensively to study their variability, like Be and Ap stars.

See the comprehensive description of the photometric system by M. Golay (1973, Vistas in Astronomy 14, 13 and 1980, Vistas in Astronomy 24, 141) for more explanations.

Record structure

No	:	Star number
V	:	V magnitude
[U-B]	:	[U-B] colour index
[B-V]	:	[B-V] colour index
U-B1	:	U-B1 colour index
B2-V1	:	B2-V1 colour index
d	:	d parameter
delta	:	delta parameter
g	:	g parameter
m2	:	m2 parameter

Database access

List of clusters

Jean-Claude.Mermilliod@obs.unige.ch
Last Update: 17 February 1998