January 25, 2013

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Misplaced Dot

image by Rick Stankiewicz, Peterborough, Ontario, Canada

Around midnight on January 23rd, I checked outside in my backyard near Keene, Ontario, Canada just before turning in for the day and upon looking up at the Moon, what did I see but a beautiful and complete Lunar Halo or ring around the Moon. This one was bright enough that I could see the colours (heavier reds) of a rainbow on the inside of the "ring", especially at the lower portion of the ring, but most of the colours are diffuse and scattered making the main ring appear whitish. Halos typically have a radius of 22 degrees, caused by refraction of light by randomly oriented hexagonal ice crystals. The added bonus this particular evening was the positioning of Jupiter right at the 4 o’clock position and right in the halo portion. Wow, what a nice coincidence to end the day. It was a little on the chilly side this evening too at -22 C, but it was calm and just the right amount of high thin cirrus cloud laden with random ice crystals to produce this atmospheric phenomenon. Once again proving it pays to be "looking up", no matter what the time of day or weather outside.

Rick Stankiewicz
Comment by CAW: Wonderful image, but why isn't the halo centered on the Moon? Also, is the vertical gray streak on the right of the halo refracted moonlight or a hazy cloud?

Related Links
Rick's astronomy club website

Yesterday's LPOD: Nectarian Ridges

Tomorrow's LPOD: The Atlas Helps Public Outreach


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