Last modified: Tuesday, April 1, 2003
STAR TRAK/April 2003
April offers a fine chance to see Mercury
Skywatchers in the Northern Hemisphere will have their best chance of the year to see Mercury during April. Binoculars may be needed early in the month, but the tiny planet will be easy to see without them after it climbs out of the evening twilight glow into a dark sky.
Start looking very low in the west about 45 minutes after sunset. Trees or buildings will be enough to block Mercury, so at the beginning of the month you'll need a clear view of the western horizon. The pinpoint of white light is easy to see when you gaze directly at it, but easy to miss if you don't know it's there when you glance at the sky. That's why so many people have never seen Mercury.
The swift-moving planet will climb noticeably higher each evening, finally peaking on April 16 when it will be above most of the obstacles that usually hide it. It will drop back toward the horizon just as quickly during the rest of the month, disappearing into the solar glare by May as it passes between Earth and the sun.
High to Mercury's upper left (south) will be bright yellow Saturn, drifting through the constellation Taurus the Bull. Saturn will be almost directly above orange Aldebaran, the brightest star in Taurus. Saturn's rings will continue to be a splendid sight in telescopes, tilted toward Earth the maximum amount and offering the best view in 30 years.
Brilliant white Jupiter will appear high in the south as the evening sky darkens, dominating the constellation Cancer the Crab and outshining everything but the moon. Close by on Jupiter's right (west) will be Cancer's special feature, the Beehive star cluster, a beautiful sight in binoculars. Jupiter will be on display for the entire evening, setting in the west during the early morning hours.
Mars will rise in the east around 2 a.m. local time, glowing bright orange in the southeast by the start of morning twilight. Mars will almost double in brightness during April, heading toward its most spectacular appearance in decades at the end of August.
Venus will finally rise in the east at the start of morning twilight at the beginning of the month, but just an hour before the sun by month's end. Though still bright enough to pick out of the solar glare, Venus will be increasingly hard to find and easily hidden behind nearby objects as it drops toward the sun.
The Lyrid meteor shower will peak on the night of April 21-22, with about 20 meteors per hour normally visible in a clear dark sky. This year, the third-quarter moon may wash out the fainter meteors. The meteors can appear anywhere in the sky, but they will seem to come from a point called the radiant in the constellation Lyra the Harp, which gives the shower its name. Lyra's bright white star Vega will be almost at the radiant, and the meteor count should be highest when Vega is well above the eastern horizon, beginning around 11 p.m. local time in the Northern Hemisphere and lasting until the moon rises around 2 a.m. The later the hour, the more meteors there will be.
Vega is part of a trio of bright white stars called the Summer Triangle. Vega is the first of them to rise each night. The others are Altair in the constellation Aquila the Eagle to the south and Deneb in the constellation Cygnus the Swan to the north. When you are looking from Deneb to Altair, you are also looking at the Milky Way, though it is usually obscured by city lights.
The moon will be new on April 1, at first quarter on April 9, full on April 16 and at third quarter on April 23.