This field should ensure that almost all of the light from Saturn and the comparison star
reach the detector.
The Magnitude scale was derived from a virtual comparison star
and is only an approximation for V mag.
The brightness of each was compared with that of two supposedly constant stars, the comparison star
and the check star that were close on the sky to the variable star.
Due to a problem with the comparison star
the data were not analyzed.
The B, V, R and I measurements of NGC 7027 were usually made first which was then followed by B, V, R and I measurements of the comparison star
The sixth column of Table I lists the comparison star
used for each measurement.
02 magnitudes when using a calibration method involving the Canopus add-on, Comparison Star
Selector, which picks comparison stars
of similar colour and magnitude to the target star.
Mu-Leonis was the comparison star
and Epsilon-Leonis was the check star for all magnitude measurements.
08 V magnitude comparison star
(TYC 3991-1480-1) together with a 10.
The comparison star
for all measurements was iota Geminorum; the magnitudes were taken from Iriarte et al.
Each measurement consisted of the sequence CSCSCSKC where C is the comparison star
measurement, S is the Saturn measurement and K is the check star measurement.
This is a different method of estimation in which you try to judge the brightness difference between the variable and just one comparison star
in steps of tenths of a magnitude.