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01 May 2015
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In May, four of the 16 stars of first magnitude or brighter visible from Southern California begin their annual leaves of absence, sinking into the western twilight glow. In order of departure, they are Rigel, Aldebaran, Sirius and Betelgeuse. In June, Procyon, Capella and Pollux will follow—all the stars of the huge Winter Hexagon, with Betelgeuse inside. It’s enjoyable and relaxing to look for these stars within an hour after sunset on clear spring evenings. Those who watch regularly are certain to notice the stars appearing lower each evening at the same stage of twilight, and eventually dropping out of view. This change is a direct consequence of Earth’s annual revolution around the sun. As seen from Earth from late April through mid-July, the sun appears to move from Aries through Taurus into Gemini, causing these zodiac constellations and their neighbors to sink into the evening twilight glow, and, after…
31 Mar 2015
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Few people will choose to arise early to catch the start of the lunar eclipse on Saturday morning, April 4, when the spring’s first full moon begins to enter the umbra, or dark central core, of Earth’s shadow at 3:16 a.m. local time. For the next 1.7 hours, more and more of the moon will be immersed in the Earth’s circular dark shadow, until the start of the total eclipse at 4:58 a.m. Even before then, the rusty color typical of the moon in deep eclipse should be noticed—at least in the lower part of the moon’s disk, closer to the center of Earth’s shadow. Totality lasts less than five minutes, as the northern (upper) edge of the moon barely passes within the outer edge of Earth’s umbra. There should be a pronounced difference in color and brightness between the top and bottom edges of the moon. Totality ends by…
27 Feb 2015
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March 2015 at dusk: Early in the month, the four brightest “stars,” in order of brilliance, are: Venus, in the west; Jupiter, in the eastern sky; Sirius, the “Dog Star,” 40 degrees up in the south as seen from the Coachella Valley; and Canopus, less than 4 degrees up when it passes due south about 21 minutes before Sirius does. From the Coachella Valley, you must choose your site carefully to see Canopus, or mountains might block your view. From my abode in Palm Springs, I see Canopus blink out when it goes behind a mountainside several minutes before it reaches its high point. From Palm Springs and Desert Hot Springs, Canopus passes due south only 4 degrees up in a dark sky at 7:32 p.m. on March 1, and then four minutes earlier each day, to 7:08 p.m. on March 7, and suddenly 8:04 p.m. on Sunday, March 8—an…