Jun 01

June 2005

Whats Up in the Sky June 2005


Summer arrives and we look forward to finally being able to go out and observe the sky without freezing or being clouded out. But, alas, we come to find that we have to wait until 11:00 p.m. before it is dark enough to see anything through our telescopes. That’s why it’s nice that this month’s viewing highlight is a gathering of bright planets that should be visible just after sunset during the last half of the month.

You may recall an earlier column in which I described how 17th century astronomers began to figure out the laws of nature through careful and accurate observations of of the planets, especially Mars. Ancient Greek observers distinguished between the fixed stars, stars that maintained fixed patterns among themselves over many generations, and the wandering stars or planets. The word planet means “wanderer” in Greek. Much of ancient astronomy was devoted to observing and predicting the motions of the planets. This month we get an opportunity to witness the daily wanderings of the planets Mercury, Venus, and Saturn.

Starting in mid-month, look in the west northwest, near the horizon, around 10:00 p.m. (or as soon as the brightest stars start to become visible). Venus will be easily recognized since it is, by far, the brightest object in the sky besides the moon. Below and to the right of Venus will be Mercury, the third brightest object after Venus and Jupiter. Above and to the left of Venus will be Saturn, much dimmer than the others. The three form a straight line.

Keep looking each night and you will notice that soon they do not line up but keep moving closer and closer together. During the last week of the month Saturn passes to the left of the other two planets and then moves below and to their lower right. Meanwhile, Mercury draws closer to Venus, passing under it and moving off to its left by month’s end. On Saturday, June 25, all three planets will fit into a field of view 1.5 degrees across. This is called a trio and the next easily observed trio won’t occur until 2010, so don’t miss it. Then, on Monday, June 27, Venus and Mercury will be separated by less than one-fourth the width of the Moon. Use binoculars to see this close encounter of the two planets and to spot Saturn just below them.

This promises to be a rare and spectacular gathering and should be easily seen since it occurs at a convenient time when chances for clear weather are better than average. It should be a great opportunity to enjoy what’s up in the sky.

Here are this month’s other viewing highlights:

  • June 6: New Moon
  • June 8: one hour after sunset, look WNW to see Venus below the crescent moon; also look for Saturn and the stars Pollux and Castor above and to the left of Venus
  • June 9: a thin crescent moon sits between Saturn and Pollux, above and to the left of Venus
  • June 14: First-quarter Moon; earliest sunrise of the year for our latitude
  • June 21: summer solstice – summer officially begins at 2:46 a.m. EDT
  • June 21-27: watch three planets gather in WNW one hour after sunset each day
  • June 22: Full Moon
  • June 27: latest sunset of the year for our latitude
  • June 28: Last-quarter Moon

Peter Burkey – SAAA President