Datatype: HPD or XY

HPD or XY represents rectangular X,Y positions of the stars in the cluster field. The cluster center has the coordinates (0,0). It is the aim of the database to have rectangular position for each star that has been numbered once in the cluster field.

XY positions have been taken from the literature as far as possible, but many fields have been measured on a Hipad Plus digitizing tablet (Houston Instruments), which gave its name (hpd) to this datatype.

Magnitudes are usually V magnitude, but could be mpg or B, if nothing else is available. There is no reference for this kind of data, but information on the data source and the unit scale, i.e. how many units to get one arc minute.

Record structure

No:Star number
X:X coordinate
Y:Y coordinate

Database access

List of clusters

Last Update: 17 February 1998