Below is a calendar of celestial events happening during the month of April, 2018.
This month, be sure to check out Jupiter, which starts rising about 90 minutes evening twilight, but it comes up earlier and earlier each week. As soon as it clears horizon obstructions in the east-southeast, it grabs the attention of any sky watcher. Telescopic views of Jupiter during April are best in the middle of the night, when the planet has gotten at least moderately high. April is also a good month to locate the Big Dipper, even though this month, it’s upside down! And Venus is visible after dusk all month.
All times Eastern Daylight Time, for the Northern Hemisphere.
April 2 —A lot is happening on Easter Monday! First, set your alarm clock for a few hours before sunrise and check out the southeast sky, as Mars slips 1.3° to the south of Saturn. The two planets are all the more eye catching because they appear practically the same in brightness (Mars is magnitude +0.3, while Saturn is just a trifle dimmer at +0.4). Then, late in the evening, look low toward the east-southeast horizon about an hour before midnight to see a waning gibbous Moon and Jupiter.
April 7 — Look to the southeast before dawn to see the waning gibbous Moon near Mars and Saturn. Saturn will be the planet closest to the Moon.
April 8 — Last quarter Moon, 3:18 a.m. In this phase, the Moon appears as a half Moon in the sky. One-half of the Moon is illuminated by direct sunlight while the illuminated part is decreasing, heading toward the New Moon (invisible) phase.
April 8 — The half-Moon will also be at apogee, its farthest to Earth in its orbit. Lunar apogee will happen less than 2 hours before the Moon reaches its last quarter phase.
April 15 — New Moon, 9:57 p.m. At this stage, the Moon is not illuminated by direct sunlight and is completely invisible to the naked eye.
April 17 — Right after sunset, look low toward the west-northwest for a view of a slender 2-day old crescent Moon, just 5 percent illuminated. And situated about a half-dozen degrees to its upper right is the steady, dazzling light of the planet Venus. Earth’s “sister planet” gets a little higher each week during April. It remains small and roundish in telescopes this month, but from early April until early September, Venus will be at least 10° above the horizon 45 minutes after sunset (though never very high), and during that period we will see its disk grow and enter its crescent phase.
April 18 – Look for the crescent Moon as it appears to float near the bottom of the beautiful V-shaped Hyades Star Cluster, marking the face of Taurus, the Bull. Initially, in the bright evening twilight, only the Moon will be visible, though once the sky has become completely dark soon after 9 p.m., the Hyades stars should be readily evident with the unaided eye.
April 20— at 10:32 a.m., the waxing crescent Moon is at perigee, its closest point to Earth in its orbit.
April 21-22 — Late Saturday night into the early morning hours of Sunday, look for the Lyrid meteor showers; this year’s prime viewing time is expected on Sunday morning (April 22nd) after the not-quite first quarter Moon has set. Its meteors are often bright. The display is usually best just before dawn, when the radiant point, 9° southwest of the brilliant bluish-white star Vega, has climbed to a point almost directly overhead. The Lyrid meteor shower has been observed for more than 2,600 years; Chinese records say “stars fell like rain” in the shower of 687 B.C. Quite spectacular displays have also been witnessed at least a dozen times since. These meteors are the dust left behind by Comet Thatcher, which visited the inner solar system in 1861.
April 21 is Spring Astronomy Day!
April 22—First Quarter Moon, 5:46 p.m. In this phase, the Moon looks like a half-Moon in the sky. One-half of the Moon is illuminated by direct sunlight while the illuminated part is increasing, on its way toward full.
April 29 — April’s Full Pink Moon will be astronomically full at 8:58 p.m. In this phase, the visible Moon is fully illuminated by direct sunlight. Though the Moon is only technically in this phase for a few seconds, it will appear full for about 3 days. This is the first full Moon of the spring season.
With information provided by contributing Astronomer, Joe Rao.