by Robert Victor

Several of the sky events this month take place close to the horizon. During my years at Abrams Planetarium at Michigan State University, we were fortunate to have a four-level parking ramp directly behind our building. Serving as our ziggurat, it provided a wonderful panoramic view of the distant western horizon, including downtown Lansing and the Michigan State Capitol Building four miles away. We, and often our public audiences, would climb the stairs (or take the elevator) to the top level to watch for planetary gatherings, the first and last visibility of individual planets during their apparitions, heliacal settings (annual last dates of visibility) of first-magnitude stars, and lunar and solar eclipses. At one time we held the record for the youngest crescent Moon ever, a hairline-thin Moon, age 13 hours 28 minutes after New, seen through binoculars from our parking ramp on May 5, 1989 (reported in the following September’s issue of Sky & Telescope magazine). Our staff led memorable public viewing sessions atop the ramp for the transits of Venus at sunrise on June 8, 2004 and at sunset on June 5, 2012. Students from elementary schools in Palm Springs joined forces with the public at a city park to observe last June’s transit for over four hours until the Sun disappeared below the horizon. (more…)

by Robert Victor

During the first week of April, Venus and the Pleiades star cluster (the Seven Sisters) appear in the same field of view of binoculars. The moon will appear close to Mars and the star Regulus on Monday and Tuesday evenings, April 2 and 3. On Friday, April 6 the moon, just past full, will appear close to the star Spica and the planet Saturn. After that, the moon rises later each night, and will return to the early evening sky in late April when it will appear as a crescent near Jupiter very low in the west-northwest at dusk on April 22, and near Venus on April 24. On April 30, the moon for the second time this month will appear near Mars and Regulus, and on May 3 and 4, the moon will appear near Saturn and Spica. The moon will be full on May 5.  (more…)

by Robert Victor

All-sky evening star charts and sky calendars for March and April 2011, illustrating events mentioned in this article, such as the moon passing planets and bright stars, and the Mercury-Jupiter pairing low in the west at dusk around March 15, can be found on the web at www.pa.msu.edu/abrams/ABDNHAMar-AprSkies/.

Follow the Moon!

The moon’s orbit stands nearly vertical in the sky soon after sunset each year in late winter/early spring for observers at mid-northern latitudes. In 2011, dates to follow the moon’s progress at dusk from thin crescent to Full are March 6-19 and April 4-17. On the first evening of each interval, the moon is not far above the horizon and the very thin crescent may be difficult to spot, especially if you have mountains to your west. Challenge your students to observe the young very thin crescent moon on Saturday, March 5, within 30 hours after new. About 25 minutes after sunset, the crescent sliver will be just 7 degrees up in the west and 13 degrees lower right of Jupiter. Notice its horns, pointing away from the sun, are pointing straight up!

For the next week, the moon climbs much higher each evening as it passes the bright stars of the zodiac. Encourage your students to face west about half an hour after sunset on Sunday March 6. Those who do so will be rewarded by the sight of a beautiful crescent moon not far to the right of Jupiter. On that date and on the next few evenings, as the sky darkens, alert your students to look for the faint bluish glow of earthshine on the moon’s dark, non-sunlit side.

By the latter half of the week of March 6-12, students may also begin to notice the planet Mercury a few degrees to the lower right of bright Jupiter. On each successive evening, Jupiter appears lower, owing to Earth’s faster revolution around the sun, and Mercury appears higher, owing to the innermost planet’s even faster revolution, until on March 15, the two planets appear to pass each other. That evening, some 45 minutes after sunset, Mercury and Jupiter are just two degrees apart, with fainter Mercury to the right of Jupiter. This will be the best conjunction, or pairing, of bright planets in the evening sky this year! (more…)