Apr 10, 2017
The Full Seed Moon Shines with Bright Jupiter, and Comets keep Coming!
Binocular Comets
There are more comets observable in binoculars and low power telescopes, although the brightening moon will wash them out a bit early in the week. Expect the comets to appear as faint greenish blobs (quite different from a star). If they develop a tail, it will point roughly away from the Sun. By the way, the comets with C/ in their names are one-time- only visitors. The ones with P/ are periodic, returning regularly every few years, and dropping the debris that produces meteor showers.
Comet C/2015 ER61 (PANSTARRS) is a pre-dawn comet that is moving eastward (towards the left) on a track sitting about 8 degrees above the star Deneb Algiedi in Capricornus (the Sea-Goat). It’s at magnitude 8 and should brighten a bit more before it swings around the Sun next month.
Comet 41P/Tuttle-Giacobini- Kresak is an all-night comet, and it is still brightening, too. At 9 pm local time, the comet is halfway up the northeastern sky, below and between the two dippers. As the week unfolds, it drops towards the prominent stars that mark the head of Draco (the Dragon). Keep an eye on it — this comet has a reputation for sudden outbursts that dramatically brighten it.
Comet C/2015 V2 (Johnson) is another brightening one. This week, it is fairly stationary, sitting above and between the constellations of Hercules and Draco. In mid-evening it is above the northeastern horizon, while after midnight it is nearly overhead. Being near the pole star, this comet stays up all night.
Brand new Comet C/2017 E4 (Lovejoy) is 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 diameters to the upper left of 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 Scheat. On Wednesday morning, it’s above the bright star Alpheratz, and by the weekend, it will be about a palm’s width to the right of the Andromeda Galaxy, and closing.
The Moon and Planets
The April full moon, known as the Full Seed Moon, Pink Moon, Sprouting Grass Moon, Egg Moon, or Fish Moon, occurs in the wee hours of Tuesday morning, so it will look full on both Monday and Tuesday night. It rises around sunset and sets around sunrise. This is the only night in the month when the moon is in the sky all night long. The rest of the month, the moon spends at least some time in the daytime sky. After Tuesday, the moon wanes and rises later.
On Monday, April 10, Jupiter, the full moon, and the bright star Spica will rise together in the eastern sky about 7:30 pm local time. The trio of objects will fit within a binocular field of view and make a nice photo opportunity. They will cross the night sky together and be visible low in the southwestern sky before sunrise.
Between midnight and dawn on Sunday, April 16, the waning gibbous moon will sit about 5 degrees to the upper right of Saturn, both fitting within a binocular field of view and making a nice photo opportunity. Just before dawn breaks they will be visible low in the southwestern sky. The following morning, the moon will jump to Saturn’s left.
Bright white Jupiter is now dominating the eastern evening sky. It reached opposition on Friday, so it will continue to show a large and bright disk diameter in a telescope. In the sky, Jupiter is just a few finger widths above Virgo’s brightest star Spica, and by dawn, the star and planet are low above the western horizon.
Around opposition, Jupiter’s four large moons, discovered by Galileo in 1609, cross in front of the planet, casting little round black shadows beneath them. A moderately sized telescope can see the phenomenon, if you know when to look. The events I list below are visible any where in the world where Jupiter is visible in a dark sky. Just correct the Eastern Daylight Times (EDT) to your time zone. (The same goes for the Great Red Spot appearances below.)
Jupiter’s moon Europa casts its shadow on the planet on Sunday, Apr 9 from 8 pm to 10:10 pm, and Sunday, April 16 from 10:30 pm to 12:30 am. Io casts its shadow on Jupiter on Monday, Apr 10 from 1:30 am to 3:30 am, and Tuesday, April 11 from 8 (in twilight) to 10 pm. The Great Red Spot is visible for about three hours centred on Mon, Apr 10 at 12:20 am, Wed, Apr 12 at 9:45 pm and Fri, Apr 14 at 11:35 pm.
For about the first half of this week, you can spot Mercury very low in the west after 8:45 pm local time. By week’s end, it’s hidden in the sunset. Dim, but very reddish Mars is still sitting, but not too high, in the western sky after sunset. It sets about 10:40 pm local time this week.
Yellowish Saturn rises in the southeast about 1 am local time, and can be spotted until about 6:30 am, when it’s 2.5 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. Rounding out the planets, extremely 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 9th) by Chris Vaughan.
