H-magnitudes of spiral galaxies

New optically normalized H-magnitude growth curves are defined for galaxies of types S0 to Im, from which new values of fiducial H-magnitude, H^g^_-0.5_, are measured for the 665 galaxies. A series of internal tests show that these four standard growth curves are defined to an accuracy of 0.05mag over the interval 1.5<=log(A/D_g_)<=-0.2. Comparisons with the Aaronson et al. values of diameters, axial ratios, and fiducial H-magnitudes show the expected differences, given the different definitions of these parameters.

The values of H^g^_-0.5_ are assigned quality indices: a quality value of 1 indicates an accuracy of less than 0.2mag, quality 2 indicates an accuracy of 0.2-0.35mag, and quality 3 indicates an accuracy of more than 0.35mag. Revised values of corrected H I velocity widths are also given, based on the new set of axial ratios defined by the RC3.