Sunrise and Sunset Times

From the U.S. Naval Observatory (Eastern Daylight Time)

Sun rises at 6:46 a.m. and sets at 7:25 p.m. on the 1st.

Sun rises at 6:03 a.m. and sets at 7:55 p.m. on the 30th.

Moon’s Phases in April

New Moon on the 5th.

Full “Pink” Moon on the 19th.

Stars and Constellations

April, the first full month of spring, signals the inevitable departure of the winter star groups from the evening sky. Aldebaran and the Pleiades cluster, both in Taurus; Betelgeuse and Rigel in Orion; and Sirius in Canis Major will all be vanishing after this month, not to reappear in the evening sky until next autumn.

Procyon in Canis Minor will stick around for another month or so, while Pollux and Castor in Gemini and Capella in Auriga will remain viewable until early June.

While the stars of winter are exiting, the stars of spring are taking center stage.

One of the most famous spring stars is Regulus, the brightest star in Leo, the Lion, which is high in the south in early evening. Arcturus, the bright yellow-orange star in the constellation Boötes, the Herdsman, is getting high in the east. The two stars are both intrinsically more than 100 times brighter than the Sun. Arcturus lies about 37 light years from our solar system, while Regulus, at 79 light years distant, is over twice as far away and therefore appears fainter.

Between about 9 and 10 p.m., another bright star, Spica, in the constellation Virgo, can be seen in the southeast. Spica is even more distant than either Arcturus or Regulus at 250 light years from Earth.

Arcturus, Spica and Regulus form the “Spring Triangle,” which is larger though not nearly as famous as its summer counterpart consisting of Vega, Altair and Deneb.

A moderately bright star, Alphard, in the constellation Hydra, the Water Snake, lies a bit below Regulus. Alphard, which means the “solitary one,” is appropriately situated in a region of the sky that contains almost no other nearby stars of comparable brightness. Alphard is an orange giant star, similar to Arcturus, but is intrinsically even brighter. Moreover, Alphard lies 180 light years from our solar system, or about five times further away than Arcturus, and so it appears noticeably fainter, comparable in apparent brightness to Polaris.

The Big Dipper, the celebrated asterism within the constellation Ursa Major, is now rising in the northeast. The middle five stars — Merak, Phecda, Megrez, Alioth and Mizar — are all about 75 to 80 light years away, while the two outer stars, Dubhe and Alkaid, are 124 and 101 light years distant, respectively.

Naked-Eye Planets in the Evening and Morning Sky

Mars, mimicking a bright orange star, is up in the southwest at nightfall. Mars’s brightness continues to diminish as Earth continues to pull away from it. Mars is now more than five times farther from Earth than it was at closest approach last July and twice as far away from Earth as the Sun. This April, Mars rides through the constellation Taurus the Bull, passing below the Pleiades Cluster at the start of the month. Mars sets around 11:30 p.m. during April.

Jupiter is getting higher above the horizon with each passing morning, and by the start of April, it lies due south at the first glimmer of dawn twilight. Shining with a cream-colored brilliance, Jupiter rises around 1 a.m. as April begins and shortly after 11 p.m. at month’s end.

Rising about 1½ hours after Jupiter, the planet Saturn makes its appearance above the southeastern horizon during the wee hours of the morning. Saturn rises around 3 a.m. on the 1st and by 1 a.m. on the 30th.

Venus still catches the eye as it hovers like a brilliant yellow star above the eastern horizon during the dawn hour, but it is slowly descending into the glow of morning twilight. Venus rises only about an hour before the Sun, around 5:30 a.m. at the start of April and by 5 a.m. at the end of the month. The time between Venus-rise and sunrise is only about one hour this April, and that already small interval will diminish further over the next several months until Venus reaches superior conjunction with the Sun in August.

The innermost planet, Mercury, hovers very low in the east at dawn this month, but it is even closer to the horizon than Venus, rising not more than one hour before sunrise. It will be difficult to spot against the bright twilight.

Information on lunar phases and rise/set times of Sun and planets is obtained from the U.S. Naval Observatory Data Services at usno.navy.mil/astronomy. Additional information comes from "The Astronomical Almanac (2016-2020)" by Richard J. Bartlett (Stars ‘n Stuff Publishing, 2015). For more information on the night sky, visit the Widener Observatory Stargazing website at widener.edu/stargazing. A set of free sky maps can be obtained at skymaps.com.

comments powered by Disqus