Mars setting, Comet Johnson in binoculars, and a crown for Spring

Spring is often crowned by numerous flowers, and there is a crown in the evening sky as well – Corona Borealis.  Comet Johnson has become visible in binoculars while Mars is sinking and the next two weeks are your last chance before we lose the planet in the glare of sunset.  Here is your guide to the sky for May 15 to 21, 2017…

Sun – Earth – Moon

Sunrise this week is at 5:03 am and sunset at 8:01 pm giving us 15 hours or sunlight as or days lengthen to the Summer Solstice in mid-June.  Last Quarter Moon takes place on Thursday at 8:33 pm.

Planets in the Sky

Mercury reaches its greatest western elongation on Wednesday, but its angle via the ecliptic is so low that it will be a challenge to find in the predawn sky before sunrise.  Instead look for Venus which rises in the east at 3:30 am. Mars is sinking in the twilight, only visible for about 30 minutes after sunset.  Jupiter shines brilliantly in the south-southeast after sunset. Saturn rises in the eastern sky around 10:30 pm and the Moon will be 3 degrees south of it on Saturday.

Constellations – A spring crown and a comet nearby

Corona Borealis, also known as the “Northern Crown” is a faint circlet of stars next to Bootes the Herdsman. The constellation is associated with Ariadne, the daughter of King Minos of Crete. Minos wife had borne a hideous monster, half-man and half-bull called the Minotaur who was locked up in a complex labyrinth.  Periodically, the Minotaur needed to be fed, and a number of Athenians would be put into the labyrinth for it to eat. On the third such feeding, the hero Theseus was one of those chosen as a sacrifice. Ariadne fell in love with him, and offered to help if he would take her away with him when he escaped. He agreed, and she gave him a thread to unwind behind him to mark his passage. He killed the Minotaur, followed the thread out of the labyrinth, and sailed from Crete with Ariadne.  All seemed well but when Theseus landed on the shore of Dia, he ruelly abandoned Ariadne.  Left all alone, was sadly lamenting her fate, when Bacchus put his arms around her.  He took the crown from her forehead, and set it as a constellation in the sky, to bring her eternal glory.   Look for Corona Borealis just to the east of Bootes the Herdsman.

Comet Johnson which is visible in binoculars this week passes between Corona Borealis and Bootes.  It currently is displaying a double tail, one of dust and an ion one as well.  The comet also known as C/2015 V2 was discovered by J.A. Johnson in November of 2015 from images taken with the Catalina Sky Survey.   It makes it closest approach to Earth on June 5 and reaches perihelion on June 12, so it should be getting brighter from now until then before starting to fade.    Do check it out!

Sky at 8:30 pm this week – Star chart courtesy of

Satellites to See…

Monday morning look for the International Space Station (ISS) from 3:33 to 3:39 AM moving from northwest to northeast.  On Wednesday morning see it from 1:52 to 1:56 am moving from north to northeast. Saturday morning try catching it from 4:03 to 4:09 am moving from northwest to east.

Grab a light jacket and your binoculars and get out there and find a comet, check out a crown while searching for it, and see if you can catch some of the planets.  Happy stargazing and keep your eye on the sky!

Shawn Laatsch

About Shawn Laatsch

Shawn Laatsch is the director of the Emera Astronomy Center and Jordan Planetarium at the University of Maine. He started his astronomy education career in 1984 and has directed planetariums in university and science center facilities, taught undergraduate astronomy courses, and given numerous lectures around the globe. He serves as President (2017 & 2018) of the International Planetarium Society, Inc. the world’s largest organization of planetarium professionals. Shawn has a passion for sharing astronomy and stargazing with people of all ages.