Fata Morgana Mirage Observed from Brittany, France

April 04, 2017

Fata_morgana_guillaume_doyen_astroguigeek (2)

Photographer: Guillaume Doyen
Summary Authors: Guillaume Doyen; Jim Foster

Shown above is a Fata Morgana mirage observed from Presqu'île de Rhuys, Brittany, France. A Fata Morgana is a form of superior mirage where the mirage image appears above the actual image. The mirage here is affecting the rather featureless island of île d'Houat, located approximately 11 mi (17 km) from the shoreline where I captured the photo. Notice that parts of the island seem to be floating or looming. Mirages such as this occur when there's a steep temperature gradient; when a layer of colder air (immediately above the seawater) is trapped below a layer of warmer air -- a temperature inversion. The temperature at the time the picture was snapped was 98 F (37 C). Under these conditions, light rays from a distant object (the island) are curved toward the eye by layers of air having different densities, caused by the abrupt temperature gradient. So it seems that the island is more or less smeared upwards into a cliff. This Fata Morgana mirage lasted for a little more than an hour.

The Presqu'île de Rhuys peninsula may experience this kind of mirage with more regularity, during the summer months, than many seaside areas because of the strong temperature gradient between the cold Atlantic Ocean and the much warmer adjacent land areas. Photo taken on July 16, 2016.

Photo Details: Canon EOS 600D camera; 70-300 mm lens; 300 mm (480 mm equivalent);| 1/800 sec. exposure; | F/7.1; ISO 100; Adobe Lightroom software; photo cropped; no tripod used.