February’s Super Snow Moon was magical in more ways than simply beautiful. The unusual mirage captured during the Moon’s rise was seen by other Cape Ann photographers as well as myself. Lisa Freed from Rockport photographed the omega shape, rising adjacent to Motif No.1.

The effect has several names including Omega Moonrise, Etruscan Vase Moonrise, and Inferior Mirage Moonrise. The omega shape is seen more often during a sunrise, so it is quite exciting that we were witness to an Omega Moonrise on Cape Ann!

From my reading, this is how I understand why it occurs:

During cold weather, when the seawater is warmer than the air, the lowermost air layer is warmed up by the water and produces a temperature difference.

This omega shape is a type of inferior mirage. The refracted (inverted) image is actually below the object’s true position. When the Moon protrudes above the horizon at Moonrise, its inferior mirage can sometimes be seen below it, where it joins the true Moon, creating an omega shape. For this mirage to occur, a layer of very warm air must lie just above the sea surface.

Omega Moonrise

A few minutes later