Tonight may be the big night for this year's annual Geminid meteor shower, but early in the evening the moon and Jupiter should put on an eye-catching display of their own.
The Geminid meteor shower occurs every year and should be going strong by 12:30 a.m. local time tomorrow (Dec. 14). Jupiter and the moon are the cosmic opening act for the Geminids, which are typically the best meteor shower of the year.
This sky map shows where to look in the southwestern sky to see Jupiter just below the moon tonight for observers with good weather and clear skies.
Jupiter and the moon will be separated by about 7 degrees of arc in the night sky. Keep in mind that your clenched fist held at arm's length measures about 10 degrees. So Jupiter and the moon should appear less than three-quarters of a fist apart.
Tips for moon-watching
The moon, of course, has always been a prime target for telescope observers everywhere and shows amazing detail in even the smallest telescope. Even binoculars will show the mare or "seas," mountain ranges, and ringed plains, as well as the great craters, while with a telescope of only 3-inch aperture you can see practically everything as clear as the very best Earth-based photos.
Most observers agree that the very best time to view the moon is now ? right at the time of first quarter and in the few nights thereafter. Currently the moon is in a good position for evening study with most of its major features visible, while not overly bright (as is the case at full phase) to cause a loss of detail through glare.
The best views are along the sharp sunrise line separating darkness from light, called the terminator. Through a telescope, features near the terminator stand out in bold relief; shadows are strong and details are more easily seen. Sometimes you can even notice bright specks of light where high mountains catch the light of the rising Sun before it has reached the plains below.
Bright Jupiter is hard to miss
While you're looking at the moon early tonight, you'll immediately take note of the brilliant silvery "star" shining almost directly below it.
That's the largest planet in our solar system: the planet Jupiter. As darkness falls, you'll see this bright pair standing due south, about halfway up in the sky.
As soon as it gets dark, those using telescopes will have Jupiter manifest its profuse embellishment of atmospheric details. A medium-size telescope may show you literally dozens of features in the restless atmosphere of this fastest spinning of worlds.
And even in steadily-held seven-power binoculars, you can glimpse the four big Galilean satellites, which will appear as tiny stars immediately adjacent to Jupiter.
In fact, if you look tonight, you'll see all four stretched outward on one side of the planet in this order: Europa, Io, Callisto and Ganymede. And Jupiter itself will remain in view until it sets around midnight.
If the cold doesn't drive you inside after Jupiter sets, the Geminid meteor shower should be getting into full swing at that time.
The Geminids will peak at about 6 a.m. EST (3 a.m. PST and 1100 GMT). And if Jupiter, the moon and a meteor shower aren't enough for you, you can stay up past sunrise and try to spot the bright planet Venus in the daytime sky.
Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.