Starry Skies Above Santa Monica

May 19-26, 2004

Mirek Plavec
Emeritus Professor of Astronomy, UCLA

   May Sun in Taurus
   The Sun left the constellation of Aries, the Celestial Ram, and entered Taurus, the Bull, on May 14. On Sunday, May 23, the Sun will rise at 5:46 a.m., four minutes earlier than a week ago, and set at 7:54 p.m., five minutes later than a week ago.
  
   The Evening Growing Moon
   The Moon is New tonight, meaning that the Moon is projected in the direction of the Sun, showing us its dark side. As the Moon orbits the Earth fairly fast, within a few days, it will be visible again — in the west, shining at first as a thin crescent.
   On Friday, May 21, the Moon will set at 10:34, which is two hours and 40 minutes after sunset, so it is possible that its extremely thin crescent (not quite 8 per cent of its disk illuminated) will be visible. It will be projected into Gemini, the Celestial Twins. The two bright stars that gave that constellation its name, Castor and Pollux, will shine close to the Moon on Saturday and Sunday evenings.
   From there, the Moon will travel through Cancer into Leo, and its bright face will grow fairly rapidly. Next Wednesday evening, May 26, you should see the Moon as half full. The real First Quarter, with one half of the lunar disk illuminated, will come later that night, when the Moon shines below Leo, the celestial lion.
  
   Venus, Mars, Saturn
   Venus, Mars, and Saturn are all projected between Taurus (the Celestial Bull) and Gemini (the Celestial Twins). Among them, Venus easily dominates. The greatest eastern elongation of Venus occurred on March 29. It’s now returning to the Sun, and will be in conjunction with the Sun in June — as seen by us.
   Planet Mars is located to the east of Venus, fairly close to it. Several stars in the vicinity are brighter, but Mars can be identified by its reddish color, and its location with respect to Venus.
   Saturn shines above the first-magnitude star Betelgeuse in Orion. It is fainter than Betelgeuse, but in a telescope, is much more interesting, with its famous rings and numerous dancing moons. However, contemporary astronomers, who are primarily interested in the distant universe, find Betelgeuse more interesting than Saturn, though they usually ignore the planet and the star and focus on the distant galaxies.
  
   The Evening Stars
   The best known among them (not the brightest) is the “Big Dipper”, astronomically known as Ursa Major, the larger bear. While it is fairly easy to see the dipper, much more imagination is needed to see the bear, which has an unusually long tail, contrary to any one you may encounter in the Sierra, or anywhere else.
   The main stars in that constellation are only of the second magnitude, and there are quite a few stars in the sky that are brighter than any star in the Big Dipper. The long tail of that imaginary bear, when projected to the south-east, points to the first-magnitude star Arcturus in Bootes, and further down to another such star, Spica in Virgo. These two stars are actually much brighter than our Sun. Spica is very luminous because its surface is much hotter than that of the Sun, while Arcturus has a cooler surface but is a giant star.