Glorious Dawn: Ice and Sun Create Rare Halos
Texas photographer Joshua Thomas captured a once-in-a-lifetime picture when he was visiting Red River, New Mexico, on the morning of Jan. 9, 2015.
Sunlight shining through ice crystals in the chilly atmosphere of dawn that day created so many different rare phenomena that it took atmospheric optics expert Les Cowley to later name them all.
Many of us have witnessed halos around the sun or moon when a high level of ice crystals were present between us and the heavenly bodies.
Seeing one often means some kind of precipitation will occur within the next 24 hours.
But the photo Thomas snapped contains nine different types of optical phenomena occurring at the same time. Each were labeled by the U.S. National Weather Service office in La Crosse, Wisconsin, and tweeted the following day.
Among the phenomena visible in the photo to the upper right (especially the enlarged version) is a 22-degree halo, which includes a sun pillar and a sun dog.
A sun dog, or parhelion, is a form of coloured spot at the same elevation angle as the sun. It typically appears about 22 degrees on either side of the sun.
A sun pillar is a column of light extending above or below the sun, and is usually seen when the sun is low in the sky.
Farther to the left and right in the enlarged version of the image is an infralateral arc, which is a halo extending 46 degrees from the sun. It is sometimes accompanied by a complimentary supralateral arc around the sun, which somewhat appears like the outer part of a double rainbow.
Sunvex Parry arcs and upper suncave Parry arcs are extremely rare and were first identified in 1820 by Arctic explorer Sir William Edward Parry during his search for the Northwest Passage.