Apr 01

April 2010

What’s Up in the Sky April, 2010
By Peter Burkey

Crescent Moon and Venus on March 17, 2010

I love my digital camera, but it has its limits. I can’t set the exposure or shutter speed (unless I set it on “fireworks” or “snow”) and I can’t manually focus the image. These limitations prevented me from getting a good shot recently of the planet Venus with a nearby, very thin crescent Moon, only 25 hours past New. The following night I was able to get a much better shot of the Moon and Venus, as shown below.

This month these two celestial objects will again put on quite a show and will be joined by the planet Mercury, which makes its best appearance of the year. Mercury can be spotted near the western horizon about one half hour after sunset to the lower right of much brighter Venus. Use Venus as a guide to finding Mercury. Binoculars will help. Look early in the month as the planet’s brightness fades each night. On April 3, the two are closest together, separated by only 3 degrees (roughly the width of three fingers held at arm’s length).

Meanwhile, two other planets are visible this month. Face south and look about two-thirds of the way up from the horizon to overhead and you will find Mars, to the left and slightly below the twin stars Castor and Pollux. Again, look early in the month as the planet’s brightness also dims as the days progress.

Saturn was at opposition on the night of March 21-22, and is visible almost all night in April. Since it is low in the east-southeast at dusk, wait several hours to get a telescopic view of its disc and rings. It can be found below the constellation Leo, the Lion.

The only other naked eye planet, Jupiter, is only visible in the predawn sky. On April 11, it can be found near the eastern horizon just below the thin crescent Moon 30 minutes before dawn.

So, get out there and enjoy viewing the planets, some of the best objects up in the sky.

This month in history:
April 4: First commercial mission to MIR – 2000
April 7: Deployment of Compton Gamma Ray Observatory – 1991
April 12: Yuri Gagarin becomes first human in space – 1961
April 12: Columbia is first space shuttle to be launched – 1981
April 14: Christian Huygens born – 1629
April 17: Apollo 13 returns to Earth – 1970
April 23: Max Planck is born – 1858
April 28: Eugene Shoemaker is born – 1928

Here are this month’s viewing highlights:
Planets this month: After sunset Saturn is in SE below the constellation Leo. Mars is high in the south, between Gemini and Leo. Mercury joins Venus near western horizon just after sunset. Look for Jupiter above eastern horizon 45 minutes before sunrise.
April 6: Last quarter Moon.
April 1-16: Look for Mercury an Venus above western horizon at dusk.
April 14: New Moon.
April 15: See Venus, Mercury, and crescent Moon above WNW horizon one hour after sunset.
April 21: First quarter Moon.
April 28: Full Moon.