As Earth's moon begins its climb in our night skies this week, the moons of Jupiter chase their shadows. Elsewhere in the solar system, the goddess of love makes her move on the god of war.
Jovian Shadows. On Tuesday, February 17, Jupiter's moons take turns making appearances. First, the shadow of Jupiter's volcanic moon Io glides across the disk of the gas giant. Watch from 6:13 p.m. to 8:31 p.m. EST.
Fellow moon Callisto ducks behind the western rim of Jupiter at 9:10 p.m. EST. Finally at 10:35 p.m. EST, Europa has its turn to play hide-and-seek as the icy moon's shadow creeps over the cloud-tops of the largest planet in the solar system.
And as an extra observing challenge, telescope users can look for the Great Red Spot, Jupiter's own monster hurricane. It rotates into view around midnight EST.
Comet Lovejoy. Late evening on Wednesday, February 19, binocular and telescope users can still catch sight of comet Lovejoy (C/2014 Q2) as it shines at fifth magnitude. The spectacular green comet has been a hit with sky-watchers since it brightened during the December holidays. (Learn more about the comet's blue-green tail in a previous viewing guide.)
The icy visitor will be passing through the constellation Perseus, named for the Greek hero, as those stars slowly settle in the low northwestern night sky.
The comet should still be fairly easy to spot with nothing more than binoculars, thanks to its proximity to the fourth-magnitude star Phi Persei.
And by coincidence, Lovejoy will be close to Messier 76, the Little Dumbbell Nebula, which is a gaseous remnant of a sun-like star. Located some 6,400 light-years from Earth, the tenth-magnitude cloud measures nearly three light-years across.
Lovejoy has remained bright for longer than expected, making it a fine target for viewing during the dark, moonless nights this week.
And now is the time to catch this icy interloper before it fades away. By the end of the month, it will dip to sixth magnitude, and by the next moonless sky window in March, Lovejoy will have dimmed to about ninth magnitude. At that point, it will still be an excellent target, but only for those with backyard scopes.
Lunar Triangle. After the sun sets on Friday, February 20, look toward the southwest for a tight triangular formation formed by a thin crescent moon, the white Venus, and ruddy Mars.
All three celestial objects will be so close together that you should be able to just about cover them with your thumb held at arm's length. The grouping will make for a pretty photo opportunity.
Venus and Mars Conjunction. By Saturday, February 21, the gods of love and war will have their closest encounter of the year in our skies at dusk.
With the moon staring down at the cosmic duo, Venus and Mars will appear to be separated by less than half a degree-about the same chunk of sky as is taken up by the full moon.