That’s what’s occurring this coming week. You’ve got Jupiter reaching its yearly “opposition” — when it forms a straight line with the Earth and Sun. Except, in 2010 it happens at the narrowest gap in our two orbits. Result: The closest visit of giant Jove in 47 years.
Just look around the sky anytime after 9 p.m., and all night long. There it is, far brighter than anything else. It’s magnitude -2.9, positively dazzling against the dim stars of Pisces.
Its closest approach is this Monday night, September 20. Binoculars pointed its way show green Uranus just above it, which by chance also hovers at its closest to Earth that same night.
Jupiter’s been weird this year. Ever since it emerged from behind the Sun this past April, it’s been missing one of its two dark belts. The southern one vanished, poof, leaving only a single stripe — an event unseen since 1973. At the same time its famous bigger-than-Earth storm, the Great Red Spot, whose name had probably not taxed the literary muse, is now clearer than ever.
This is when you want to drag out that old telescope, the one gathering dust. Point it at the night’s brightest “star” after 9 p.m. when it’s high-enough up. Odds are 50-50 the GRS will be visible.
If not, wait a few hours. Jove’s superfast 10-hour spin brings the Red Spot (which is actually orange this year) into view at some point every single night. You’ll also see its four giant moons.
The enemy of Jovian detail is star-twinkling. If stars are twinkling that means the air over your head has different temperature layers, bending light. On those nights Jupiter will look blurry, its GRS hard or impossible to see. Try again tomorrow. No need to rush. Jupiter will look wonderfully big for the next couple of months.
The next pair of sky-events is just two nights later, Wednesday, September 22. That’s the Harvest Moon, defined as the full moon nearest to the fall equinox. This year no head-scratching is required to figure out which full moon falls closest to that September 22 or 23 date. The two happen the very same night! If you like precision, the equinox (when the Sun hovers directly over the equator, marking the start of autumn) happens Wednesday night at 11:09 p.m., while the moment of full moon is just six hours later at 5 a.m., a couple of hours before sunrise.
Ignore any newscaster or calendar that suggests the Harvest Moon is Thursday night. By then 15 or more hours will have elapsed since the Moon was full. It won’t even look perfectly round Thursday night. It will be officially full early Wednesday before dawn, meaning Tuesday night is the night. Anyway. . .
The Harvest Moon happens right on the equinox once every 30 years. A super-close visit of Jupiter hasn’t occurred since 1963. Jupiter meeting another planet on its opposition night hasn’t happened for at least half a century.
It’s all coming together this week. Monday through Wednesday nights. In Pisces.
Look for it, in a sky near you.