The Ghost of Halley’s Comet
You don’t have to wait until 2061 to delight in its offspring
A thin sliver of the waxing crescent moon rises Thursday evening just after sunset, its tips pointing almost straight up. Look a few degrees below its outside curve for Aldebaran, the orange eye of Taurus the bull. High above the moon is Jupiter, shining brighter than any star-like object.
Friday evening the moon has halved the distance from Jupiter, which is 20 degrees — two fist-widths held at arm’s length — straight up. To the moon’s left is Betelgeuse, the shoulder of Orion. Far to the south is Sirius, the brightest star. Sunset Saturday reveals the growing moon just 10 degrees below Jupiter in the west. Betelgeuse is almost equidistant below the moon. By Sunday, the moon is less than 10 degrees to the south of Jupiter.
Far to the east of Jupiter is Mars. Shining at magnitude –1.2, the red planet is brighter than any star except Sirius. Compare it to Spica, in the constellation Virgo, 10 degrees to the east. At 11pm Mars is at its highest and is due south. It sets around 4:30am.
Saturn, the dimmest of the naked-eye planets, trails well behind Mars. But as the ringed planet nears opposition May 10, it puts on its best face. Look for it rising in the east around sunset, a steady golden glow amid the much dimmer stars of Libra. The rings are opened at roughly a 20-degree angle, and are easy to discern in even a modest telescope.
As the darkness begins to fade, Venus rises in the east, blazing at magnitude –4.2. The Morning Star is so bright that you can still find it in the east an hour after sunrise.
If you’re up waiting for Venus, you may spot a streak of light crossing the heavens. This is the annual return of the Eta Aquarid meteor shower, which peaks Monday and Tuesday. This should be a good showing, as the first-quarter moon sets just after midnight. The meteors appear to emanate from the constellation Aquarius, but they can appear anywhere on the celestial dome. The best viewing is in the nether hours between midnight and dawn, when it could rain up to 30 meteors an hour. While not likely to produce a great storm, the Eta Aquarids are steady, stretching out a couple weeks before and after the peak.
Twice a year the earth passes through a stream of debris left in the wake of Halley’s Comet. While the famed comet only visits the inner solar system every 75 years, it has been doing so for millennia, leaving ring upon ring of jetsam with each passing. These countless bits of ice and dust date to the formation of the solar system, and as earth plows into them, they ignite upon contact with our atmosphere. At the other side of the sun, earth crosses Halley’s path again in the fall, resulting in the Orionid meteor shower.