Mercury and Mars in Evening, the Moon Manifests an X on Monday, and Venus meets new Comet Lovejoy!
Two Binocular Comets
Comet 41P/Tuttle-Giacobini-Kresak is still brightening, and can be spotted in binoculars or a small telescope this week. The young crescent moon will set early, leaving the evening sky fairly dark all week. As darkness falls around 8 pm local time, the comet is halfway up the eastern sky. By midnight, it is high overhead, below the Big Dipper. It’s moving downwards now, landing midway between the bend in the Big Dipper’s handle and Kochab, the brightest star in the Little Dipper. I posted a diagram here. Expect the comet to appear as a faint greenish blob (quite different from a star). If it develops a tail, it will point roughly away from the Big Dipper. Keep an eye on it — this comet has a reputation for sudden outbursts that dramatically brighten it.
Another comet has recently been discovered by Australian amateur astronomer Terry Lovejoy — his sixth! Designated Comet C/2017 E4 (Lovejoy), it’s well within the brightness range of small binoculars or sharp eyes under dark skies. This week, it is in the pre-dawn eastern sky about three fist diamaters above Venus and travelling eastward (to the left) through Pegasus (the Winged Horse). Sunday, it’s a few finger widths to the left of the star Enif. On the weekend, it passes close to the bright star Sheat.
Lunar X on Sunday Evening
A few times a year, for a few hours around the First Quarter Moon, a feature called the Lunar X becomes visible in strong binoculars and small telescopes. When the rims of the craters Parbach, la Caille, and Blanchinus are illuminated from a particular angle of sunlight, they form a small, but very clear and bright X-shape. It’s located on the terminator about one third of the way up from the southern pole (bottom) of the Moon (at 2° East, 24° South). The prominent round crater Werner sits to the lower right.
The next Lunar X will form in early evening about 6:30 pm Eastern Daylight Time on Monday, April 3, peak around 7:30 pm as darkness falls, and last until at least 8:30 pm. This is a global event for observers wherever the Moon is in a dark sky during that period, adjusting for your difference from the Eastern Time zone. The Moon will be nicely positioned in the western sky. Let me know if you see it!
The Moon and Planets
The moon reaches First Quarter on Monday afternoon, so it will appear half illuminated on Monday night. This week we get the best evenings of the moon’s monthly cycle for observing it. The slanted sunlight casts dramatic shadows on the moon, hightlighting new regions every night as the terminator boundary marches across the creamy disk. On Thursday, the now much fuller moon, lands only two finger widths to the right (southwest) of the bright star Regulus in Leo (the Lion). On Sunday night, April 9, the almost full moon lands a fist’s diameter above Jupiter, moving even closer the following night.
Speaking of Jupiter, the bright giant planet reaches opposition on Friday, the day of the year when we are closest to it. It rises at sunset, about 8 pm local time, and shows the largest and brightest disk diameter in a telescope. In the sky, Jupiter is just a few finger widths to the upper left of Virgo’s brightest star Spica, and by dawn, the star and planet are low above the western horizon. Visible in a good backyard telescope, Jupiter’s moon Io casts its round black shadow on the planet on Sunday, Apr 2 from 11:35 pm to 11:45 pm EDT. Europa casts its shadow on Jupiter on Sunday, Apr 9 from 8 pm to 10:15 pm EDT. The Great Red Spot is visible for about three hours centred on Sun, Apr 2 at 11:30 pm EDT, Wed., Apr 5 at 1:20 am EDT and at 9:10 pm (soon after Jupiter rises), Fri., Apr 7 at 10:30 pm EDT, and Mon, Apr 10 at 12:30 am EDT.
This week, Mercury completes its best evening apparition of the year for mid-northern latitude observers. It’s visible low in the west after 8:30 pm local time. Next week, it starts to drop into the sunset again. Much dimmer, reddish Mars is still halfway up the western sky after sunset, and is setting about 10:45 pm local time this week.
Yellowish Saturn rises in the southeast before 2 am local time, and can be spotted until about 6:30 am, when it’s two fist diameters above the southern horizon. During this summer’s Saturn season, the bright reddish star Antares in Scorpius (the Scorpion) is less than 20° to the right (southwest) of the planet.
Bright white Venus precedes the sun in the eastern morning sky, rising after 5:30 am local time. A telescope will reveal that it is showing a thin crescent phase.
Stargazing News for this week (from April 2nd) by Chris Vaughan.