PHOTOELECTRIC AND CCD PHOTOMETRY OF E AND S0 GALAXIES

We present BR photoelectric photometry for 352 E and S0 galaxies that are part of a large survey of the properties and peculiar motions of galaxies in distant clusters. Repeat measurements show our internal errors to be 2-3 per cent in B and R and 1-2 per cent in B-R. Comparisons of BR and BVR reductions for 10 galaxies also observed in V show small systematic errors due to differences between the spectral energy distributions of stars and galaxies. External comparisons with B - V colours in the literature confirm that these colours are good to 1 per cent. We also describe R-band CCD observations for 95 of the galaxies and place these on a BR photometric system for photoelectric and CCD photometry, with a common zero-point good to better than 1 per cent. We find the rms precision of both our photoelectric and CCD R magnitudes to be 2-3 per cent for galaxies as faint as R almost-equal-to 15. Errors in galaxy magnitudes of this order introduce errors of less than or similar to 2 per cent into D(n)-sigma distance estimates, corresponding to errors in peculiar velocities for single galaxies of less than or similar to 200 km-s at a distance of 1 0000 km s-1.