A guide to keep you informed about the night sky over Oneonta, NY, brought to you by the astronomer at the SUNY College at Oneonta.

Monday, April 30, 2012

Transits, eclipses, and meteors...oh my!

Ever since Venus and Jupiter made a wonderful pass by each other last month, Venus has been dominating the evening sky after sunset. Shining brilliantly in the western sky, Venus has passed its greatest eastern elongation (the point where it is farthest east of the Sun - visible in the evening) and is now on its way back into the sunset glow for the upcoming transit in front of the Sun on June 5th. This will be something nobody alive wants to miss, as the next one won't happen for another 105 years! Until then, we Oneonta residents will hope and pray for clear skies that day. For now, there are still some exciting things to come.

The United States is not often blessed with the opportunity to view a solar eclipse, but this month we will be...in part, anyway. An annular solar eclipse will be visible in the southwestern portion of our country on May 20.
If you live in New Mexico, Arizona, Utah, Nevada, or California (or will be there on vacation) you will get the chance to see the Moon almost block out the Sun completely. Annular eclipses happen when the Moon lines up perfectly with the Sun in our sky, but is at a point farther away in its orbit around the Earth than average. This results in the Moon having a slightly smaller angular size than the Sun, producing a ring of sunlight around the New Moon instead of being completely blocked out. While not quite as spectacular as seeing a total solar eclipse, annular eclipses are also amazing to watch and certainly, beggars can't be choosers!
Here in Oneonta, we will see a partial solar eclipse beginning around 5:15 p.m. on May 20 and continuing on until sunset. Even though we won't be able to see totality from our location on the Earth, I still plan on viewing this event if our skies are clear. If you plan on viewing the eclipse, be sure to use appropriate eye protection. I will probably use a telescope fitted with a solar filter. More on the eclipse as the date gets closer.

More immediately, we have another meteor shower coming up. On the night/morning of May 4th/5th, the Eta Aquarid meteor shower will be visible. This meteor shower is one of two that derive from the dusty trail of Halley's Comet (the other being the Orionids) and, while not a particularly active meteor shower, can produce 10-20 meteors per hour at its peak. While its radiant won't rise until the early hours before dawn on May 5th, it is usually better to look about 90 degrees away from the radiant anyway to see those dust particles that give us a glancing blow. Viewing after midnight is recommended, but unfortunately this year the Full Moon's overwhelming brightness may hinder attempts to see all but the brightest streaks across the sky. It's still worth a look, however. Additionally, since the maximum technically occurs during the Oneonta afternoon, if you are clouded out on the night of May 4th you can try again on the night of May 5th. Here is a chart showing the radiant of this meteor shower as it is rising in the early hours before dawn in early May:

Happy viewing!