All programme stars including standard stars were observed with the standard RI filters of the Johnson system with a 20-arcsec diaphragm for 4 nights during the 1982–83 observing season. A photoelectric photometer attached to the 1.2 meter reflecting telescope of the Japal— Rangapur Observatory was used for these observations. A dry-ice cooled EMI 9558B photomultiplier tube was used as the detector and the photo-current was recorded by means of a GR 1230A DC-amplifier and a Honeywell Brown chart recorder.

The extinction coefficients for R and (R-I) were determined from the observations of standard stars taken from the list of Johnson (1966) and also from the observations of an early and a late spectral type star on each night and all the observations were corrected for atmospheric extinction. The instrumental magnitudes of a programme star were transformed to the standard system through normal procedures.