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Astronomy/The ring around moon

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Expert: Steven LJ Russo - 12/13/2007


Question
Hello Steven, I often use to observe the sky with naked eye and with a telescope. Amateur I should say. While observing moon with naked eye, I have seen a ring around it(not like the one Saturn has) which has different diameters for different days. Its merely a light, but I have always wondered how this forms around moon. Not all days I have seen this, occasionaly I see this and also during rainy seasons. All the reason I have given may not be correct ! Can you explain how this gets formed.
Thanking you in expectation.
Mohan

Answer
The ring around the Moon is caused by cirrus clouds up in the atmosphere.  Those couds are about 5 - 7 miles up, where the temp is about 70 degrees below zero, so the clouds are made of ice crystals.

The Moons light passes through the crystals like light pasing through a prism, so you get a halo. Some are small and some large.  The large halo usually means precipitation sometime during the next 36 hours.

Steve

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Steven LJ Russo

Expertise

As a space science educator in a planetarium, my work centers around teaching people about the night sky and the solar system. I have a strong background in those areas, plus the history of NASA and spaceflight, and meteorology.

Experience

Experience in the area. I have been an amateur astronomer for 47 years, and have been teachng space science in planetariums for 34 years. For 15 years I was a radio and television meteorologist, and for the past 20 years I have been a space science writer for two newspapers in New York State. I am a member of the Middle Atlantic Planetarium Society and the International Planetarium Society. I have had a number of articles published in several astronomy journals, including "The Constellation" and the "Planetarian". Education/Credentials. I hold a B. S. from Wagner College and an M. S. from State University of New York at Oswego. Awards and Honors. I have been awarded the "Fellows" award from the International Planetarium Society for more than 20 years of continuous service in the planetarium field.

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