Originally Published Astronomy.Com
Monday, April 6
If you head outside after darkness falls tonight and look due west, you’ll see the stars of Taurus the Bull about one-third of the way to the zenith. The V-shaped Hyades star cluster, which forms the Bull’s face, points straight toward the horizon. To the right of the Hyades lies the spectacular Pleiades star cluster (M45) and to the left are the glittering jewels that form Orion the Hunter’s shape.
Uranus is in conjunction with the Sun today. From our earthly perspective, this means the distant planet lies behind our star and thus remains out of sight. Uranus will return to the morning sky in May.
Tuesday, April 7
The Moon travels approximately 13° relative to the background stars every 24 hours, and this motion carries it to Saturn’s vicinity tonight. Although the two solar system objects rise around 11 p.m. local daylight time this evening, they climb higher and move closer to each other after midnight. By 4 a.m., they will be just 3° apart and some 30° above the southern horizon. (The Moon passes 2° north of the planet at 9 a.m. EDT.)
Europa occults Io the evening of April 8 starting just a minute after the scene shown here. Less than two hours later, Europa eclipses Io.
Astronomy: Roen Kelly
Wednesday, April 8
Although Jupiter reached opposition and peak visibility two months ago (on February 6), it remains a stunning sight from dusk until it sets around 4 a.m. local daylight time. The brilliant planet shines at magnitude –2.3 and stands due south and nearly 70° above the horizon as twilight fades to darkness. Jupiter’s westward motion relative to the starry background comes to a halt today at a point just 5° east-southeast of the Beehive star cluster (M44) in Cancer. Typical 7x50 binoculars will show them both in the same field of view. If you target the giant planet through a telescope, you’ll see its 41"-diameter disk and lots of atmospheric detail. Also pay attention tonight to the moons Io and Europa — Jupiter’s third- and fourth-largest satellite, respectively. Europa partially occults Io for five minutes starting at 11:51 p.m. EDT; Europa will eclipse Io for four minutes beginning at 1:38 a.m. EDT tomorrow morning.
Thursday, April 9
Although the calendar may say it is spring, the so-called Winter Hexagon remains prominent on April evenings. One of the sky’s largest asterisms — a recognizable pattern of stars separate from a constellation’s form — the hexagon stands out in the western sky after darkness falls. To trace this asterism, start with southern Orion’s luminary, Rigel. From there, the hexagon makes a clockwise loop. The second stop is brilliant Sirius in Canis Major. Next, pick up Procyon in the faint constellation Canis Minor, then the twins Castor and Pollux in Gemini, followed by Capella in Auriga, Aldebaran in Taurus, and finally back to Rigel.
Mercury passes behind the Sun from Earth’s perspective this evening. Although the solar glare hides Mercury, the innermost planet’s rapid motion will carry it into view after sunset in just two weeks. This will be the start of Mercury’s finest evening appearance of the year for Northern Hemisphere observers.
Venus appears near the Pleiades on April 10, much like it did the evening of April 10, 2007, when the star cluster lay just above the planet on the right side of this image.
Friday, April 10
Brilliant Venus dazzles in the western sky after sunset all week. But tonight offers a special treat as the planet passes 3° south of the stunning Pleiades star cluster (M45). The pair remains on view from twilight until after 10 p.m. local daylight time. Binoculars will deliver the best views of this dramatic conjunction. If you turn a telescope on Venus, you’ll see a disk that spans 15" and appears about three-quarters lit.
Saturday, April 11
Last Quarter Moon arrives at 11:44 p.m. EDT. It doesn’t rise until around 2:30 a.m. local daylight time tomorrow morning, however, and will climb well above the southeastern horizon as dawn approaches. Throughout this period, the half-lit orb lies among the background stars of Sagittarius the Archer, northeast of that constellation’s Teapot asterism.
Sunday, April 12
With the Moon’s glare diminished now that our satellite has waned to a crescent, it’s a good time to view Saturn. The ringed planet shines at magnitude 0.2 among the background stars of northern Scorpius, a region that climbs highest in the south around the time twilight begins. This morning, the planet lies 0.8° northwest of magnitude 4.1 Nu (ν) Scorpii. If you target the planet through a telescope, you’ll see its 18"-diameter disk surrounded by a beautiful ring system that spans 41" and tilts 25° to our line of sight.