Ernie Wright wrote:
canopus56 wrote:
snip all
Are you sure about that? Schaefer makes the opposite assumption.
...[C]onsider the case of two stars with equal V magnitude but
different color. An observer using day vision would pronounce the
two stars to be of equal brightness, whereas if night vision were
being used the redder of the two stars would appear fainter. (1990
p. 212)

Thanks Ernie. Shortly after posting I realized I had read the
correcting factors backwards and deleted the post (at least out of the
Google groups archive). The point of the color index correcting factor
in Schaefer's algorithm is to adjust what the eye sees to a V-band
standard. The Schaefer algorithm and Bogan's javascript calculator
should adjust the perception of red color index stars (which the eye
overreports in apparent brightness due to the Purkinje effect) to a
dimmer white color in the V band. Bogan's javascript calculator is
right. I just plain had a brain fart on this one and read it wrong. -
Canopus56