May Night Sky
Good time to view elusive MercuryBy Larry Mahon
Agate Ridge Observatory
The elusive planet MERCURY presents a twilight spectacle during the first couple of weeks this month. This is the best view we will have until next year.
In order to view it you will need to be where you have a very low west-northwest horizon. Looking about 30 minutes after sunset on May 1, the planet will be approaching the PLEIADES, as it moves away from the Sun. It will be the brightest "star" within 10 degrees of this horizon.
On May 6, the thin crescent moon will be just above the planet. Both objects will set before the sky is completely dark.
MERCURY'S greatest elongation, 22 degrees from the Sun, occurs on the evening of May 13. After May 18, the planet will have lost most of its brightness and contrast as it again approaches the glare of the Sun.
Locating the smaller planets is always a challenge if you don't follow them on a regular basis. Planets are always moving through the sky in relation to the stars. The planet MARS moves about 1/2 degree per day returning to a position near the EARTH every two years.
Observing this motion is hard to do in a telescope or binoculars unless MARS is near a reasonably bright star to use as a reference. An excellent opportunity to see this motion will occur low in the Western sky on May 22, and 23, when MARS plunges through the Beehive Star Cluster (M-44) in the constellation of Cancer.
The Beehive is located in front, to the west, of the sickle forming the head of LEO the lion. If you watch carefully you should be able to continually track the planet as it moves 1.4 seconds of arc per minute, moving its own diameter every 3 1/2 minutes.
Depending where you view from you may see a conjunction or two. Even if you don't see a conjunction the passage through the Beehive should be an event you won't forget.
NASA's Phoenix spacecraft is scheduled to land in MARS' north polar region on May 25, to study the frosty soil.
Another step in the exploration of our solar system was taken on Jan. 14 of this year when the NASA spacecraft Messenger flew past the planet MERCURY.
This fly-buy, 33 years after Mariner 10 took the first close photos of the planet, passed only 125 miles above the surface and its photographs show more detail than were seen before.
The spacecraft will make two more fly-buys before it brakes and settles into orbit around the planet on March 18, 2011, for more close-up studies.