Saturday, April 7, 2012
What: A beautiful full moon arcing over the sky at Shelburne Farms. The first two shots show moon rise (around 10pm). The thin layering of altocumulus clouds produced the perfect setting for a beautiful irridescent corona. Coronas form around the sun as well, but the sun's bright light often obscures the optical light show. They are formed when light reflected off the moon is diffracted - when light bends around an object, which is different from refraction where light actually changes direction and speed - by individual water droplets. Thus the size of the aureole (the brighter inner white part) depends on the size of particles the light is bending around; the smaller the particles the larger the radius. The third image shows the moonset (around 6:15am).
Ecological notes: It was a beautiful night. We've had weather consistently around 40-50 during the day and 30 at night. The clouds have been light and beautiful the past couple of nights with brief glimpses of moonlight dancing between them.
Other notes: On Thursday, a friend's dad, Fred Homer, showed me the shells of a box turtle and a wood turtle. I read in a Joseph Bruchac book that turtles have 13 plates (called scutes) in the middle of the top of their shell (called a carapace, the bottom half is called a plastron). The central and coastal scutes are bordered by the marginal scutes. From another source, I remember reading that there are 28 marginal scutes. I only counted 25 around the edge and found that this number is far more plastic than the 13 central scutes. Bruchac, and many others, connect the 13 scutes to the 13 moons in a year. It would have been convenient to have 28 marginal scutes to connect to the 28 days in a lunar cycle. But alas, most of our turtles have 25 marginal scutes (only mud and musk turtles have 23).