Specifications

AUTOSTAR CCD PHOTOMETRY 79
Determining γ and ζ
ri
A plot of ((R – I) – (r – i)
o
) versus (R – I) has the slope (1 – 1 / γ)
and intercept ζ
ri
/ γ, from which the values for γ and ζ
ri
can be
calculated. The slope (1 – 1 / γ) has a value near zero and can be
determined more accurately than the simple slope γ.
Table E-9 lists the data and Figure E-5 shows a plot of the data.
The equations are in the form of an equation for a straight line:
((R – I) – (r – i)
o
) = (1 – 1 / γ) * (R – I) + ζ
ri
/ γ.
Table E-9. ((R - I) - (r - i)
o
) versus (R - I) Data.
(R–I) – (r – i)
0
(R – I)
0.5698 –0.0280
0.5449 0.6440
0.5969 0.4380
0.6070 0.2780
0.6103 0.3280
0.6377 0.2920
0.5424 0.3250
0.5556 0.4990
Figure E-5. ((R–I) – (r–i)
o
) versus (R–I) Plot.