Specifications

76 AUTOSTAR CCD PHOTOMETRY
Figure E-3. ((V – I) – (v– i)
o
) versus (V– I) Plot.
Slope = (1 – 1 / α)
(1 – 1 / α) = [Δ((V – I) – (v– i)
o
)) / Δ(V – I)]
Δ((V – I) – (v – i)
o
)) / Δ(V – I) = –0.260 / 1.800
(1 – 1 / α) = –0.1444
α = 1 / (1 – (– 0.1444))
α = 0.8738
α is (V – I) Color Coefficient
Y-Intercept when MX = 0 is ζ
vi
/ α.
Y-Intercept = ζ
vi
/ α
ζ
vi
= α ∗ Y-Intercept
ζ
vi
= 1.3400 ∗ 0.8838
ζ
vi
= 1.1843
ζ
vi
is (V – I) Zero Point