What’s Up in the Sky – May, 2015
Close Encounters of the Planetary Kind
By now, everyone reading this column knows about the evening planets Venus and Jupiter. For several months Venus has dominated the western sky after sunset. Lately Jupiter can be found nearby, high in the southwest, but it’s closing in on its brighter companion.
In fact, over the next three months, the celestial highlight will be the convergence of Jupiter and Venus. This is the perfect event for the casual observer with no equipment as well as the seasoned veteran amateur astronomer anxious to log a rare conjunction.
So, start now. Find a spot with a clear view of the western horizon (or as close as possible) and go out about an hour after sunset to familiarize yourself with the players in this drama.
Start with Venus, bright in the west, and Jupiter, higher up and to the left (toward the south) of Venus. If it’s not too late and you have a clear horizon, you should be able to see Orion’s belt due west. Look straight up from that to find the Gemini twins, Castor and Pollux, about half-way between Venus and Jupiter. If you draw a line starting at Venus through Jupiter and a little beyond, you will find the star Regulus in the constellation Leo, the Lion.
Use these objects in the following weeks to track the progress of the planets as the separation between them decreases steadily until, on the night of June 30, they will appear to be closer than the width of the full Moon! That’s why you want to start noticing these guys now, so on June 30, you can look at them and say, “. . . now that’s cool! I remember when they were way far apart.”
There is another advantage to making this a long-term observing project. As time goes on, the two planets get closer and closer to the horizon by the time the sky darkens. That means having watched their progress for several weeks, even if it’s only once every few days, can make it easier to find them later on.
On May 21, the crescent Moon joins the planets, now lower near the horizon but still easily visible. On the 23rd it will be next to Jupiter and on May 30, Venus will be in line with Castor and Pollux.
So be on the lookout for two bright planets coming together up in the sky.
This month in history:
May 5: Alan Shepard becomes first American in space – 1961
May 9: Hyabusa, first spacecraft to bring back sample from an asteroid, is launched – 2003
May 14: Skylab is launched – 1973
May 18: Hubble Space Telescope serviced for the 23rd (and last)time – 2009
May 25: President Kennedy gives speech challenging nation to land astronaut on Moon before the end of the decade – 1961
May 29: First experimental test of Einstein’s General Theory of Relativity performed during total solar eclipse – 1919