What’s That Bright Star At Dawn?

Venus has returned to easy viewing in the dawn sky. Created with Stellarium

Several people have asked me in recent days what that bright “star” is shining near the sun at dawn. It’s Venus, brightest of the planets. Venus was in inferior conjunction with the sun on March 25, the date it wrapped up its evening sky run.

During inferior conjunction, a planet passes between the Earth and sun moving from east to west in the sky. We get our last glimpse of the planet in the western sky at dusk. After it’s lost in the solar glare for about a week, it swings to the other side of the sun and reappears in the eastern sky at dawn. Mercury and Venus both orbit closer to the sun than Earth, so they’re the only ones that can undergo inferior conjunction.

As Venus orbits the sun, it catches up on the slower Earth and passes it. Right now, we see Venus just past inferior conjunction to the right of the sun in the morning sky. Credit: ESO with annotations by the author

Venus was too close to the sun to see easily until a week or so ago, which explains why I’ve been getting a lot of questions.  As April becomes May and mosquitos make their first tentative appearance, the planet will climb higher and get easier to see. Venus will be with us before sunrise until early December.

Through even the smallest telescope, the planet looks just like a crescent moon. If you start now to observe it, you’ll be able to watch it slowly fill out to full phase come fall. Superior conjunction, when Venus lines up with the sun once again, but this time on the opposite side from Earth, occurs on Jan. 9, 2018, the date the planet returns to begin an evening shift.

Saturn is now very easy to find because it stands straight up south about two fists above the horizon at the start of dawn. Created with Stellarium

Saturn’s the other bright planet in the morning sky; it’s in Sagittarius and about two fists high due south at the same time the very first blush of dawn appears in the east. With no moon in the morning, if you find a dark sky, you’ll see that the Milky Way runs right past Saturn, arching high up into the southeastern sky. The only other bright object near the planet is Antares, a red supergiant star not quite three fists to the right (west) and 620 light years away. April is a splendid time to enjoy a mosquito-free view of the Milky Way in pleasant temperatures.

Mars, Aldebaran (brightest star in Taurus the bull) and a narrow moon appear together in the western sky during evening twilight tomorrow. Created with Stellarium

Jupiter dominates the evening sky and is now well up in the southeast at nightfall, its brilliance unmistakable. Mars still hangs in the western sky during the first half of evening twilight like a Millennial who won’t move out of the basement. Faded now to magnitude +1.6, you’ll find it about 8° above the very thin crescent moon and about the same distance to the right of Aldebaran Thursday evening April 27. Binoculars will provide you with a last look at the Seven Sisters star cluster or Pleiades.

Winter’s time and stars are past. Spring and summer’s stars and planets now rule the roost.