Orthochromatic Photography 
WAVE-LENGTHS OF THE PRINCIPAL FRAUNHOFER LINES. 
Fraunhofer line Wave-length Colour 
A 7594 
a 7186 Red 
B 6867 
C 6563 Bright red 
D: 5896 Yellow-orange 
D, 5890 
E 5270 Green 
b, 5184 
b, BLS iy 
b, 5169 
b, 5168 
F 4861 Bright blue 
G 4308 Indigo blue 
g 4227 
h 4101 
Fi 3968 Violet 
i 3960 Violet 
K 3934 Ultra-violet 
L 3821-3816 Ultra-violet 
M 3728 Ultra-violet 
N 3581 Ultra-violet 
O 3441 Ultra-violet 
P. 3361 Ultra-violet 
QO 3287 Ultra-violet 
R 3180 Ultra-violet 
& 3100 Ultra-violet | 
al 3021 Ultra-violet 
U 2948 Ultra-violet 
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