Saturday: You probably didn’t know this but several British New Wave bands were really into astronomy. Take the band “Dead or Alive” (please). The original lyrics to their song “You Spin my Round (Like a Record) were thought to be: “ You spin me right round, baby, right round, like the Whirlpool Galaxy, right round, round, round.” (Well, that’s what I thought them to be.) The Whirlpool Galaxy was the first galaxy observed to have a spiral shape. Since then, astronomers have discovered many galaxies, including our own Milky Way Galaxy, have a spiral shape. Go to astronomy2009.nasa.gov/observe_apr.htm for more information about the Whirlpool Galaxy. Go to your small telescope to find the Whirlpool Galaxy in the night sky. It is in the constellation Canes Venatici, the hunting dogs. At 10 p.m., find Alkaid, the end star of the Big Dipper handle, five fists held upright and at arm’s length above the northeast horizon. The Whirlpool Galaxy is two fingers to the upper right of Alkaid.
Sunday: Mercury and Venus are about a fist and a half above the west horizon at 8 p.m. Venus is the brighter object. They’ll be neighbors in the sky for the next few nights.
Monday: Mars is about six and a half fists above the south horizon at 9 p.m.
Tuesday: This morning’s last quarter moon is in the constellation Sagittarius the archer.
Wednesday: This April, the hot topic in the tabloids is Sandra Bullock and Jesse James. (No, not that Jesse James.) Last April, the “Hot Topic” for the International Year of Astronomy was galaxies and the distant universe (astronomy2009.nasa.gov/topics_apr.htm). When Galileo turned his telescope to the seemingly continuous band of light in the sky, he discovered it consisted of countless faint stars. This extended our celestial neighborhood from a few thousand stars to millions of stars. This neighborhood configuration lasted until the 1920’s when Edwin Hubble discovered that there are other galaxies with millions, or even billions, of stars just like our own galaxy. We may lose interest in celebrity break-ups but galaxies are always hot.
Thursday: This evening, Mercury is as far away from the Sun in the sky as it will get this orbital cycle and at its most favorable viewing position of the whole year. This "farthest away" point is known as the planet's greatest elongation. Since Mercury is in evening sky, it is east of the Sun. Thus, this evening’s elongation is known as the greatest eastern elongation. (If you care to remember this in general, remember both eastern and evening start with the letter "e".) Mercury is about a fist and a half above the west horizon at 8 p.m. Over the next few weeks, Mercury will move toward the Sun and into the morning sky.
Friday: Saturn is about four fists above the southeast horizon at 10 p.m.
The positional information in this column about stars and planets is typically accurate for the entire week.
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