Presented at the 87th Annual Meeting of the AAVSO,
October 31, 1998; revised June 13, 1999
Results of the V-Magnitude
Experiment - 1998, designed to characterize the vision of the "average
observer," are discussed. Over 650 individual observations were analyzed,
submitted by 63 observers worldwide. These data lead to summary conclusions in
two important areas: (1) effect of star color on observed star magnitude, and
(2) the range of observation scatter expected for observers usingperfect comparison star sequences.
Quantitative color response measurements for 48 individuals, when compared to
the "average observer," show variations generally consistent with measured
levels of observation scatter. Based on these data, a color coefficient value
of b = 0.21 is recommended for translating Johnson magnitudes (UBV) into
visual magnitudes (mv).