Friday, April 20, 2007

Last night Molly observed a beautiful sight. In the early evening the waxing crescent Moon and Venus were present together in the southwest sky, with a separation of less than 5 degrees. Venus has been gradually brightening this month, from a magnitude of -4.02 at the beginning of April. It will continue to brighten to -4.11 by the end of April. Venus shines brightest when it is in a crescent phase. Yesterday the globe of the Moon was plainly outlined, even it dark portions. The star Aldebaran in the constellation Taurus was shining a rusty red to their left, and the Pleiades were visible to the lower right of the Moon. Capella was a bright star higher in the sky to the right (north). Tonight Venus will appear beneath the crescent Moon (yesterday it was to the right/south), but the sky conditions here in Winnipeg are such that Molly will probably not be able to view this event. As a side note Saturn (see previous posts on this blog) was plainly visible almost due south just down from the "hook" of the constellation Leo.
Anyways, at the time of viewing Orion was low in the southwest. Soon it will no longer be visible as spring springs more fully. This is the last chance to observe the stars of Orion the Hunter before he departs until the fall. Please refer to the graphic above for what follows: a mini-tour of the sights of Orion. Orion is a constellation visible in both the northern and southern hemispheres (though the appearance differs). In Australia the "belt" of Orion is often referred to as "the saucepan". Orion's belt is also called "the three kings" in some places. In Sumeria this constellation was referred to as "The Shepherd of Anu". In ancient Egypt this constellation was associated with Osiris, the god of the underworld. The Greek mythology of Orion the Hunter, however, is that which has penetrated most deeply into popular western culture. Orion figures in works of literature from 'Paradise Lost' , Tennyson, Tolkien and numerous other books, comics, musical works to Star Trek and Stargate,Atlantis. Orion has also figured in native American and Australian aborigine mythology. In Norse mythology Orion's belt was known as 'Frigg's distaff'. The Bible mentions Orion 3 times (Job 9:9, Job 38:31, Amos 5:8). The Greek myths generally revolve around the goddess Artemis falling in love with the hunter Orion. She was apparently so entranced that she forgot her duty of illuminating the night sky (Artemis was a Moon goddess). Her twin brother Apollo supposedly saw Orion swimming in the sea and dared his sister to hit what seemed to be only a spot on the horizon with her bow. Artemis, being more accurate than the US military, "hit the spot". When she found what she had done she placed his body in the sky. This apparently explains why the "face in the Moon" looks sad. A variant ending to the myth is that Apollo summoned a giant scorpion (the constellation Scorpio) which stung Orion to death. The result was that Scorpio and Orion could never appear together in the sky. Scorpio is a summer constellation.
Look to the illustration above. The two most prominent stars are Rigel at the lower right and Betelgeuse at the upper left.Betelgeuse is a red giant (the colour is apparent to the naked eye as a yellow orange) with an diameter probably larger than the orbit of Mars. It is an irregular pulsar that varies from 0.3 to 0.6 in magnitude. It is somewhat dimmer than Rigel, a large blue white star. Rigel at 0.1 magnitude is one of the brightest stars in the sky. Rigel has three stellar companions invisible to the naked eye. The star Bellatrix is the apparent "left shoulder" or Orion in the diagram (to the right of the viewer actually). The star Saiph is at the lower left of the rectangle that describes the main part of Orion. The "head" of Orion is Meissa, just above a line drawn from Bellatrix to Betelgeuse. The three stars of Orion's belt are named (from right to left) Mintaka, Alnilam and Alnitak. Just below this is the "sword of Orion". The "tip" os Orion's sword is the star Hatsya. In this are one may see a faint blurry area that is the famous Orion Nebula (M 42). this overlaps with a multiple star system called the Trapezium. The famous Horsehead Nebula is just below the leftmost star, Alnitak, in Orion's belt.
Orion can be used as a celestial landmark to find many other stars and constellations. Sirius, the brightest star in the night sky can be found by drawing a line to the left from the belt of Orion. Aldebaron, the "eye of Taurus", can be found by drawing a line rightward through the shoulders. A diagonal line from Rigel through Betelgeuse leads you to Castor and Pollux in the constellation Gemini. A line drawn leftward through the shoulders leads you to Procyon , another bright star in Canis Minor. Sirius is in Canis Major.

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