It's not often that so many celestial events come together at nearly the same time. But from Wednesday night to Thursday morning, we can enjoy a bundle of them.
The only glitch may be the weather. The forecast calls for "mostly cloudy" skies Wednesday night as this cool, dry, high-pressure system moves east and pumps in more heat and humidity for Wednesday and Thiursday. But Wednesday and Thursday are both expected to be sunny, or mostly so. So perhaps we'll get lucky. Here's the rundown:
Wednesday night will be the night of the full Harvest Moon. Moonrise for Baltimore will occur at 6:26 p.m. EDT. If you're still enjoying this glorious extended summer at the beach, look for the moon to pop over the Atlantic horizon a bit earlier, at 6:20 p.m.
The moon won't be perfectly full until 5:18 a.m. Thursday morning. But no one will be able to tell the difference. It's still, officially, the night of the Harvest Moon. So enjoy.
The Harvest Moon, by the way, is defined as the full moon closest in time to the autumnal equinox. That, as it happens, occurs 11:23 p.m. EDT on Wednesday evening, so it would be hard to get a much more definitive Harvest Moon.
Also appearing on this busy evening is the planet Jupiter, which many skywatchers have been admiring for weeks (see posts below) as it gleams brightly in the eastern sky after sunset. Jupiter was at opposition early this morning, directly opposite the sun as seen from Earth.
The Earth reaches opposition with Jupiter once a year, as both planets orbit to the same side of the solar system. That also makes it their closest approach of the year.
And it takes Jupiter 12 years to circle the sun once. So once on each of Jupiter's orbits of the sun, it passes perihelion - the point in that slightly lopsided orbit that is closest to the sun and therefore also to the inner planets, including Earth.
This year, opposition and Jupiter's perihelion are occuring at nearly the same time. That makes this the nearest Earth and Jupiter will be until 2022. Amateur astrophotographers are having a field day with Jupiter. There's a gallery of their images here.
So if you have a pair of binoculars, or a small telescope, or if you can find one of Baltimore's street-corner astronomers, take a few minutes to get a look at Jupiter. Even in binoculars, Jupiter appears as a round disk, not a point of light. And if you hold the glasses steady enough, you should be able to pick out as many as four of the planet's Galilean moons, strung out like tiny beads on either side of the planet.
Even if you just step outside this evening, or Wednesday evening, and look with only your eyes, you're sure to be impressed by Jupiter's brilliance in the evening sky, and the moon's. Jupiter remains in the sky all night this month, rising from the east to its highest point at midnight, before moving toward the western horizon before dawn.
Which brings us to the third event of the night of Sept. 22/23. Soon after the Harvest Moon begins climbing into the eastern sky, look for Jupiter to rise close behind it. The two brightest objects in the sky this month will be in "conjunction" on this evening, separated by about the width of your hand held at arm's length.
No charge. Enjoy.
(PHOTOS: Top: AP PHOTO, Tom Thompson, Peninsula Daily News, Port Angeles, Wash., 2004. Bottom: Jupiter in 2009, AP/NASA)