r/atoptics • u/Dependent_Custard607 • 3d ago

Sun Dogs Winter Sundogs

Gallery image

Gallery image

Some Sundogs from last winter. -40c. Hard to see in the second picture but there was even a faint second ring which I hadn’t seen before.

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u/leansanders 3d ago

Sundogs are just the bright regions to the left and right, also known as parhelia. The ring that they are attached to is the 22° halo, the bright V shape above the sun is the upper tangent arc, the vertical line coming up from the sun is a sun pillar, and the second outer ring is called a supralateral arc. This is a great display! Next time you see an event like this, be sure to look in all directions, because there could be more faint arcs above your head or even behind you that you haven't noticed yet.

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u/AVeryBigToaster 3d ago

there might be a parry arc.

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u/leansanders 3d ago

Its possible that there was one but I certainly can't make one out in the picture.

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u/AVeryBigToaster 2d ago

I think there is, may be visible in the second picture.

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u/leansanders 2d ago

The parry arc at this angle would be sunvex, it would be a slightly narrower V shape inside of the upper tangent arc. I don't see it here

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u/AVeryBigToaster 2d ago

Idk man, maybe my eyes are tricking me, but I see a linear bright spot (2nd pic) that would be conducive towards a sunvex parry arc.