If you grab a telescope and target the Moon this evening, you can watch a few points of light evolve into a prominent letter X. Focus on a spot along the terminator — the dividing line between lunar day and night — almost halfway from the equator to the south pole. Use the twin craters Aliacensis and Werner as guides to the Lunar X, which lies just to their northwest. In the image above, the X is just beginning to show. Although the X is just a chance alignment of light and shadow as the Sun rises over a group of crater walls, it’s fun to see because it triggers our brain’s pattern-recognition ability.
Tuesday, February 12
You can find the First Quarter Moon high in the south as darkness falls, then watch as it sinks toward the western horizon throughout the evening hours. Our satellite officially reaches First Quarter phase at 5:26 p.m. EST. The Moon lies in western Taurus, some 10° south of the Pleiades star cluster (M45).
You can use Mars as a guide to find Uranus through binoculars or a telescope tonight and tomorrow night. Both planets lie on the border between the constellations Pisces the Fish and Aries the Ram. This evening, Mars stands 1.0° north-northwest of its neighbor; tomorrow night, the Red Planet lies 1.1° due north of its neighbor. Both worlds show up nicely through binoculars or a telescope at low power, though only a scope reveals the planets’ disks. Mars measures 5.7″ across while Uranus, despite lying 12 times farther away, spans 3.5″. Neither object shows much, if any, detail, but the ruddy color of Mars contrasts nicely with the blue-green of Uranus.
Wednesday, February 13
The waxing gibbous Moon marches eastward relative to the background stars of Taurus this evening, passing through the conspicuous Hyades star cluster. Although everyone in North America will have wonderful views of our satellite’s journey, those farther east will see Luna centered in the V-shaped cluster shortly after darkness falls. Binoculars should provide the best views of this beautiful encounter.
Thursday, February 14
One of the sky’s most familiar constellations rules January’s sky from dusk until after midnight local time. Orion the Hunter appears conspicuous in the southeast as darkness falls and climbs highest in the south around 8 p.m. It then stands about halfway to the zenith from mid-northern latitudes. The waxing gibbous Moon stands above Orion this evening, while the night sky’s brightest star, Sirius, trails about an hour behind the Hunter.
Friday, February 15
Mercury returns to the evening sky in mid-February. This evening, it appears 5° high in the west-southwest 30 minutes after sunset. It shines at magnitude –1.1, bright enough to show up against the twilight glow. (If you don’t see Mercury right away, binoculars will bring it into view.) A telescope reveals the planet’s disk, which spans 5.6″ and appears nearly full. By the end of February, the innermost planet will be much easier to see as it climbs 11° above the western horizon a half-hour after the Sun goes down.