I photographed this awesome sight while doing field work out on the Black Rapids Glacier in the eastern Alaska Range. The view is to the southeast and you can see the Loket Tributary flowing into the main branch of the glacier center-right. Living in Fairbanks (a little under 100 miles north of here) we get to see a lot of optical phenomena from ice in the atmosphere. In the winter we frequently see halos and parhelia (sun dogs). It’s pretty rare to see the tangent arc and even rarer to see a parhelic circle – the line that continues ‘horizontally’ from the sundog. At times this made a full 360° circle around our heads from camp.