Starry Night: A stellar month for astronomy buffs

Posted Wednesday, May 4, 2011 in Features

Starry Night: A stellar month for astronomy buffs

Planetary conjunction that can be seen this week.

by Tristan Radtke

The first half of May is a great time to view a number of interesting events in our night sky. With the moon entering its new phase early in the month, early May will bring a tight grouping of our planetary neighbors: Mercury, Venus, Mars, Jupiter and Saturn will all rise within about an hour just before sunrise, offering a chance to view each of them (although Saturn may be a trickier prospect – it will rise the earliest, but is also the dimmest and will likely require a telescope to see properly). Venus, Mars and Mercury will each enter true conjunction with Jupiter in the early days of the month, with Mars passing closest at only 24 minutes distance on May 1.

While that might seem like enough of a boon for planet-watchers this month, early May is also host each year to the Eta Aquariid meteor shower. The Eta Aquariid shower takes its name from the star in Aquarius from where it appears to emanate, Eta Aquarius, but the actual source of the shower is the dust cloud left behind by Halley's Comet. While the Eta Aquariids begin near the end of April, the peak of the shower is generally around May 6, which this year will occur around a particularly good moment for meteor viewing: a new moon.

The stars

Visible in the southern night sky is the kite-shaped Bootes, the Herdsman, Leo, and the beautiful little crown of stars, Coma Berenices. Low on the horizon, look for Libra, with its characteristic diamond shape.

The planets

• Mercury: Mercury, Venus, Mars, Jupiter and Uranus will all be in close proximity to one another this month. Rising around 4:45 a.m., Mercury will rise just below a much brighter Venus, making it a bit easier to spot.
• Venus: Venus will take its place in the tight grouping of our local neighbors, rising around 4:45 a.m. In a diagonal line towards the rising Sun, Venus will provide a good anchor to view Mars and Jupiter, which will rise just before sunrise, as well as Uranus, which will be visible in the opposite direction from the sunrise. 
• Mars: Mars and Jupiter will spend the early month in conjunction, then remain near each other in our early morning sky into mid-month.
• Jupiter: Jupiter will rise around 5 a.m. this month, and it will be joined in conjunction with Mars on May 1, Mercury on May 10, and Venus on May 11.
• Saturn: Saturn is visible high to the northeast at the beginning of the month, setting around 4:30 a.m. By mid-month it will set earlier, around 3:30 a.m.
• Uranus: Uranus will take a dim role in the group of planets, rising ahead of the pack around 4:15 a.m. By mid-month, however, it will move the most away from the other planets, rising at around 3:20 a.m.
• Neptune: Neptune will start the month rising around 3 a.m., and by mid-month it will have moved farther into the evening sky, rising around 2 a.m.
• Pluto: Pluto will rise at 11:30 p.m. all month and will be situated in the M25 Open Cluster, which rises just above Sagittarius, providing both an excellent chance to spot Pluto (with a sufficient telescope) and a wonderful stargazing opportunity.

The moon

The moon will wane to its new phase on May 3, providing a dark sky for the early month events. By May 10 it will reach first quarter. It will be full on May 17, and wane to third quarter by May 24.

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