Tangent arcs

tangent arcs

A halo in the form of an arc tangent to a circular halo.

The most common of these are the upper and lower tangent arcs to the halo of 22°. They form separate arcs when the sun is low, but as the sun climbs they join to produce the circumscribed halo. These arcs are explained by refraction through the 60° prism sides of columnar crystals oriented with their long axes horizontal.
See 46° lateral arcs.

INDEX
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
0
1
2
3
4
5
6
7
8
9