Bassin Arcachon Info

Rare phenomenon in the Basin sky

If you had the chance, this Tuesday, 2019 May 7 in the early morning, to look up to the sky and observe the movements of the sun, you may have fallen on what is called the phenomenon of the three suns. It is a strong>parhélie/strong>, a rather rare optical phenomenon. An image that did not fail to capture strong>Gujanais Cédric Hurbes, going to the station of Biganos/strong>.

The appearance of three suns, or helion, is a very rare phenomenon because it requires the coordination of several elements. Two replicas of the Sun appear on either side of the star, on a horizontal line called “parhelical circle”, which may or may not be apparent. The parhelion occurs when the sun is quite low and that the atmosphere is filled with ice crystals, present in the clouds at high altitude.

Also known as “false sun” or “double sun”, the optical phenomenon is related to the solar halo. The higher the sun is in the sky, the farther the parhelions are from the central halo.

This is usually more common in polar regions as many low clouds are charged with ice particles. But it was on the Basin that we met this morning