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CALL web site
for Astronomical Sciences
Binzel Method - Target Field
By measuring a series of C and V images of the target field (comparisons and targets),
you find several values that help reduce to standard magnitudes.
The average differential value in C between target and
the comparisons (<Diff> in the Reductions Values form)
The average instrumental magnitude of the target in V
(<Std Inst> in the Reductions Values form).
The "anchor point" in V, which is found using
the <Std Inst> and Ref Offset values in the Reductions Values form.
The shift required to convert the value from step 1 to
the value in step 3 (assuming the target was the same brightness in all measurements).
This shift is stored in the Std. Shift field of the Reductions Values form.
Once all these values are found and saved, it's easy to convert C observations of the
target to the Johnson V system.