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Monthly Notices of the Royal Astronomical Society


Department of Physics and Astronomy


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 BR. 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 ≈ 15. Errors in galaxy magnitudes of this order introduce errors of ≲ 2 per cent into Dnσ distance estimates, corresponding to errors in peculiar velocities for single galaxies of ≲ 200 km s-1 at a distance of 10000 km s-1.