All for your viewing pleasure he dutifully dragged himself out of bed at 4AM, drove to the Berkeley Marina, carried his camera and tripod in the dark up a hill covered with ankle-high dew-soaked grass (accidentally stepping in a large shoe-soaking mud puddle on the way), and finally set up where he had a view across San Francisco Bay, where he could photograph the setting partially eclipsed moon over Marin County, right next to Mount Tamalpais. I hope you are appreciative! (Actually, he had a very selfish reason for doing this. He wanted a “matching bookends” image to go with his image of a rising partially eclipsed Super Moon over Canyon de Chelly in Arizona that he took in October of 2015 and sent out to Lookout Observatory fans back then.)

For those of you who weren’t paying attention to all the talk, a “Blue Moon” has nothing to do with it’s color, but today refers to the second full moon in any calendar month. (Originally it had a slightly different meaning, referring to an extra full moon within any 3-month season, but why split hairs?) It occurs approximately once every 3 years. A “Super Moon” is a recently invented term referring to a full moon that occurs when the moon is at the point in its elliptical path around the earth where the moon is closest to the earth. Therefore the full moon looks slightly larger and brighter than it usually does. Astronomers refer to this point of closest approach to the earth in the moon’s orbit as the perigee point. So you can impress your friends when they talk about a Super Moon by saying, as you look down your nose, “Oh, you mean when the full moon is at perigee?” A Super Moon occurs on average a couple of times a year. A total eclipse of the moon occurs whenever the moon in its orbit around the earth passes entirely inside the earth’s shadow cast from the sun. For this to happen the sun, earth and moon have to be very closely lined up. (This is referred to as “syzygy,” another good word to impress your friends.) Because the moon’s orbit is tilted compared to the earth’s orbit around the sun, the moon usually passes above or below the earth’s shadow when it is on the opposite side of the earth from the sun. A total eclipse of the moon occurs on average every 1 or 2 years. A totally eclipsed moon often looks red because the earth’s atmosphere scatters the blue light, but bends (refracts) the red light and directs some of it on to the moon. Of course, the occurrence of all three of these events at once is a fairly rare event.

The first picture was taken near maximum eclipse, when the moon, about 20 degrees above the horizon, was fully within the earth’s shadow, and it has the usual reddish color. A few stars are also visible. (All pictures were taken with a Canon camera with a 200mm telephoto lens.)

The second picture was taken when the moon was about 2 degrees above the horizon. Mount Tam rises to the left. The houses along the shore are about 10 miles away. The fishing boat at lower right makes the moon, still in partial eclipse, look quite large by comparison. The bird ahead of the boat is much closer, since it looks about one quarter the length of the boat! The early morning haze over the water makes the whole view somewhat blurry, and thin clouds briefly covered the moon.

The last picture is a wider view with the peak of Mt. Tam to the left 15 miles away; the half-set, still partly-eclipsed moon to the right; and a half dozen birds (Terns, I think) scattered across the picture. This was just a couple of minutes before sunrise, the end of an adventure.

Keep looking up,

Carter, (sometime) Resident Astronomer,

Lookout Observatory