Minnesota Starwatch 2021

Minnesota Starwatch by Deane Morrison, designed to inform the broadest possible community of the appearance of the nightly sky and current activities in newspapers, continues to be published in several newspapers throughout the state.

Contact:
Deane Morrison
University Relations
(612) 624-2346
morri029@umn.edu

SEPTEMBER 2021

Deneb, Cygnus, Northern Cross, Vega and Lyra, high in the south at nightfall in September

With daylight slipping away, September’s skies make an excellent background for watching stars and planets.

Venus shines briefly above the western horizon after sunset. On the 9th, a young crescent moon joins the planet. As both sink, the brilliant star Arcturus, in Bootes, the herdsman, comes out above them.

At nightfall, the Teapot of Sagittarius hangs low in the south. Its spout tips downward as if pouring the tea onto the tail of Scorpius. A little further west of the Teapot glows Antares, the scorpion’s red heart.

East of the Teapot, Saturn and brilliant Jupiter dot the darkness. Moving east again, the Great Square of Pegasus is gaining altitude.   

Above Saturn and Jupiter, the Milky Way courses through the large Summer Triangle of bright stars. If you haven’t seen the Triangle stars and constellations yet, September is the best month to check them out. Turn your binoculars on the brightest of the three stars: Vega, in Lyra, the lyre. Enjoy its brilliance and the almost perfect parallelogram of stars right below it. Those stars represent the lyre of the mythical Greek musician Orpheus. Also look for the Northern Cross, which extends from Deneb—the least bright star in the Triangle—and outlines the body of Cygnus, the swan. 

A waxing moon shines above Antares on the 12th, below Saturn on the 16th, and below Jupiter on the 17th. The moon becomes full at 6:55 p.m. on Monday, the 20th. It rises shortly afterward, so it will be very round as it climbs into the pale but rapidly darkening sky. Because this is the closest full moon to the fall equinox, it’s also the harvest moon. The harvest moon got its name because, at this time of year, the moon moves rapidly northward as it waxes to fullness and begins to wane. As a result, the moon rises relatively earlier from night to night, cutting the time farmers have to wait for a source of light for harvesting their crops.  

The fall equinox arrives at 2:21 p.m. on the 22nd. At that moment the sun crosses the equator on its way south and Earth will be lighted from pole to pole.

AUGUST 2021

Full moon, Jupiter, Saturn, Fomalhaut facing southwest, predawn August 22

Jupiter and Saturn are at their best of the year this month, thanks to Earth lapping them in the race around the sun. 

When Earth laps a planet, the event is called opposition because Earth passes directly between the planet and the sun, making the planet appear opposite the sun in the sky. Therefore, a planet at opposition rises around sunset and sets around sunrise. 

Saturn is at opposition on the 2nd, Jupiter on the 19th. On those dates, the respective planets will be up all night. They will also be near their maximum brightness for the year, although the difference will hardly be noticeable, given how far out Jupiter, and especially Saturn, orbit. The planets’ average distances from the sun are 484 million miles for Jupiter and 886 million miles for Saturn.

Traveling the night sky below and slightly east of the planets is Fomalhaut, dubbed “the loneliest star” for its status as the only bright star in its patch of sky. Its constellation—Piscis Austrinus, the southern fish—ranks among the dimmest. 

Venus still hovers close to the horizon after sunset, coming out slightly farther south from night to night. And in the morning sky, the familiar winter constellations rise earlier every day en route to their annual comeback.

The Perseid meteor shower is expected to peak the night of the 11th-12th, but the nights on either side of it may be just as good. The best time is usually after midnight. With no moon to interfere, this is a favorable year for the shower.    

August’s full moon arrives shortly after moonset the morning of the 22nd. As it nears the western horizon, the plump setting moon will shine against a pale predawn sky. This one qualifies as a blue moon according to one definition: the third of four full moons in a season. Why the third, rather than the fourth, was designated special is complicated, but what’s not to love about a summer with four full moons?

JULY 2021

Sagitta, Altair, Delphinus, Aquila facing southeast, last week of July, 90 minutes after sunset

Venus glimmers in the sun’s afterglow, where it will stay for months to come. Look for the planet low in the west-northwest about 40 minutes after sunset. The best days may be the 11th and 12th, when a young moon hovers nearby.

In the southern sky, the summer stars have taken center stage. Grab a star chart—or find one online—go out at nightfall, and start by locating the Big Dipper in the northwest. Follow the curve of its handle to brilliant Arcturus, a star whose path cuts down through the plane of the Milky Way. Arcturus anchors the kite-shaped constellation Bootes, the herdsman.

Moving eastward, we first encounter Corona Borealis, the Northern Crown, accentuated by its bright star Alphecca (or Gemma). Next comes an hourglass of stars outlining upside-down Hercules. 

Then we meet the large Summer Triangle of stars. Brightest is Vega, in Lyra, the lyre. To Vega’s lower left is Deneb, the tail of Cygnus, the swan. Deneb is also the brightest star in the Northern Cross, whose long section extends below Vega. Farther below Vega shines Altair, in Aquila, the eagle. East of Altair, little Delphinus, the dolphin, seems to leap toward a dark sea. Above it floats skinny Sagitta, the arrow.

Low in the south, gigantic red Antares marks the heart of Scorpius. Just east of Scorpius sits the Teapot of Sagittarius, with its spout pointing toward the scorpion’s tail.

By month’s end, Saturn and Jupiter, in that order, will be rising in the southeast before midnight. Look for them below Altair. Or catch them in the southwestern predawn sky; note that they form a triangle with Fomalhaut, the lone bright star in Piscis Austrinus, the southern fish. Earth is catching up to both planets in the orbital race and laps them in August.  

July’s full moon rises within an hour of perfect fullness the evening of the 23rd. Though not designated a supermoon, it will still be close, and thus bright as well as quite round.

JUNE 2021

Jupiter, Saturn, Waning Moon facing south one hour before sunrise June 27

June has three big events in store for us: the summer solstice, the last of 2021’s three supermoons, and a partial eclipse of the sun.

First up is the solar eclipse, which will be in progress at sunrise on the 10th. Here are the times when the eclipse will be at its maximum in towns in the four corners of Minnesota, along with the percent of the sun’s face that will be covered at that moment: Pipestone, 5:45 a.m., 1.1%; Hallock, 5:31 a.m., 28.4%; Grand Marais, 5:07 a.m., 63%; and Winona, 5:31 a.m., 13.4%. To see it, make sure you have a clear view of the eastern horizon, and even though the sun will be very low, watch it only with proper eye protection.

Second, the summer solstice arrives at 10:32 p.m. on the 20th, when the Northern Hemisphere tilts most sharply toward the sun. At that moment a space traveler would see Earth lighted from the Antarctic Circle to the North Pole and beyond to the Arctic Circle on the dark side of our planet. 

Last comes June’s full moon, which qualifies as a supermoon by virtue of its closeness. It rises the evening of the 24th, near the juncture of the lid and handle of the Teapot of Sagittarius.

Because June’s full moon is unusually close, its new moon, being at the opposite point in the same lunar orbit, is unusually far away. As seen from some far northern regions of the globe, that new moon lines up so well with the sun on the 10th that if it were closer, it would produce a total eclipse. Instead, those areas see a rare annular eclipse, where the dark moon is encircled by a ring of bright sun.

Jupiter and Saturn begin rising before midnight in mid- to late June, and they’re well up in the southeast to south before dawn all month long. Between the 27th and 29th, watch the waning moon pass below the planets in the morning sky. In the evening sky, Venus hovers near the west-northwestern horizon, in the sun’s afterglow.

MAY 2021

Antares and Moon, facing southwest, 90 minutes before sunrise May 26 "Supermoon" in Crown of Scorpius

As the winter constellations head into the sunset, Mars struggles to avoid the same fate.

May Day finds the red planet on course to glide between the bright stars Procyon, in Canis Minor, to the east and Capella, in Auriga, the charioteer, to the west. At the end of the month, Mars will be close to Pollux, the brighter Gemini twin. All the while, the planet is steadily dimming and, despite its relatively fast orbital motion eastward, sinking toward its inevitable exit from the evening sky this summer.

In the southeast to south, Spica, Virgo’s only bright star, is outshone by brilliant Arcturus, high above it in Bootes, the herdsman. To Spica’s lower right is a misshapen rectangle of stars marking Corvus, the crow.

To the north, the Big Dipper—part of Ursa Major, the great bear—begins the month upside down, “spilling its water” on Polaris (the North Star) and Ursa Minor, the little bear. To identify Polaris, follow the “pointer stars” at the end of the Big Dipper’s bowl. Bracketing Polaris are two brilliant stars: Capella, in the northwest, and comparably bright Vega, in Lyra, the lyre, in the northeast. During the course of a night, or from night to night, this arrangement changes as the sky rotates counterclockwise around Polaris.

In the predawn sky, look for Jupiter and dimmer Saturn low in the southeast. Thanks to the resurgent sun, we have to get out earlier each morning to see them against a dark sky.

The night of the 25th-26th, May’s full “supermoon” will be large and luminous as it slips through the Crown of Scorpius, a line of three stars near Antares, the scorpions red heart. The moon undergoes a total lunar eclipse on the morning of the 26th, but sets before the moment of perfect fullness and also before the eclipse reaches totality.

This will be the year’s closest full moon. It reaches perigee, the moons closest approach to Earth in a lunar cycle, only about nine and a half hours before reaching fullness. It edges out the runner-up, April’s supermoon, by a razor-thin margin. According to NASA, May’s full moon will be closer than April’s “by about 98 miles, or about 0.04 percent of the distance from the Earth to the Moon at perigee.”

APRIL 2021

The Sickle, Moon and Regulus, facing south, mid-evening April 21

Spring is now in the sky as well as the air. And nothing’s springier than Leo, the lion.

In April Leo dominates the southern sky after nightfall. Look for the backward question mark of stars known as the Sickle, which outlines the lion’s head. The dot of the question mark is Regulus, Leo’s brightest star. To the east, a triangle of stars mark the hindquarters and tail. On the 21st, a waxing gibbous moon hovers near the Sickle. 

The night of the 26th, a full “supermoon” crosses the sky behind Spica, the only bright star in Virgo, the maiden. Fullness comes at 10:33 p.m., less than three hours after moonrise. So this will be not only the second closest full moon of the year, but, as it clears the eastern horizon, one of the largest and roundest.  

That night the moon forms a tall triangle with Spica and brilliant Arcturus, the jewel of kite-shaped Bootes, the herdsman. As dawn starts to break on the 27th, the triangle will have moved to the west. Also, its base will have broadened as a result of the moon’s motion eastward against the background of stars during the night.

In the morning sky, Saturn and Jupiter are now high enough above the southeastern horizon for easy viewing. Go out an hour before sunrise to see them against a dark sky. Jupiter is lower and brighter than Saturn, and no bright stars are close enough to be confused with them. As the days go by, both planets rise earlier, even as they move slowly and steadily apart. Their increasing separation is due to Jupiter’s faster motion eastward in its orbit. 

Between the 1st and the 4th, a waning moon rolls through the stars of Scorpius and Sagittarius in the morning sky. On the 6th, a fat crescent rises below Saturn, and the next morning a slightly thinner moon rises below Jupiter.

The Lyrid meteor shower has a broad peak, spanning from the 16th to the 25th. It’s predicted to be strongest in the predawn hours of the 22nd, when it should sprinkle a dark sky with 10-15 meteors per hour. Meteors will radiate from high in the south-southeast, near the brilliant star Vega, in Lyra, the lyre.

 

MARCH 2021

Waxing Moon, Mars, Aldebaran, Hyades & Pleiades as seen facing SW between 8-10pm on March 19

Winter may seem endless by the time March rolls around, but this month the sun and the day length are both climbing at top speed.

At our northern latitude, the day length is increasing by about three minutes a day. The rate of change peaks at the vernal equinox, which this year arrives at 4:37 a.m. on the 20th. At that moment the sun crosses the equator on its journey north and an observer in space would see the Earth lighted from pole to pole.

Saturn and Jupiter are reentering the morning sky, but they won’t get high enough for easy viewing till at least mid-month. However, on the 5th, binoculars may help you catch Mercury immediately to the left of Jupiter in the sun’s foreglow, just above the east-southeastern horizon. A better bet that morning is the last-quarter moon hanging above the red star Antares in Scorpius.

On the 14th, the moon begins trekking across the evening sky. On the 19th, it visits Mars as the red planet glides above the V-shaped Hyades star cluster. Next to the Hyades shines Aldebaran, the eye of Taurus, the bull. On the 22nd, the moon appears below the Gemini twins Pollux (the brighter) and Castor.

On the 25th a hefty gibbous moon appears in the spring constellation Leo, the lion. The moon sits in the Sickle of stars outlining the lion’s head, between Regulus, Leo’s brightest star, and Algieba, a double star system that also contains a planet. On the 28th, March’s full moon rises in Virgo. As twilight fades, brilliant Arcturus, in Bootes, the herdsman, comes out to the left of the moon.

The faint zodiacal light glimmers in the west after nightfall during the first half of the month. A broad finger of light pointing up from the horizon along the sun’s path, this phenomenon is caused by sunlight glinting off dust in the plane of Earth’s orbit. 

FEBRUARY 2021

Aldebaran, Hyades, Pleiades and Mars as seen facing south at 7 pm on the 12th of February

February evenings offer some of the best conditions for viewing the famous winter constellations. This year they approach Mars from the east, ending the month with the Pleiades star cluster closing in on the red planet. Meanwhile, the rising of Scorpius brings a hint of summer to the morning sky.

The brightest stars in the winter constellations form the corners of the Winter Hexagon. To see it, start at the top with Capella, in Auriga the charioteer, and move counterclockwise through the other corners: Pollux, the brighter Gemini twin; Procyon, in Canis Minor, the little dog; Sirius, in Canis Major, the big dog; Rigel, in Orion; and Aldebaran, in Taurus, the bull. If you start instead at Aldebaran, you can trace a “G” by turning when you get to Rigel and finishing at Betelgeuse, Orion’s right shoulder.

While viewing Orion, aim your binoculars at his sword—a line of stars that seem suspended below the three stars of his belt. On a clear moonless night, you can see, even with the naked eye, a colorful, hazy “star” about halfway down the sword. This is the Orion Nebula, a chaotic cauldron of starlit gas and dust whipped by interstellar winds. At 1,300 light-years away, it is the closest large stellar nursery, where new stars—and potential planetary systems—are being born.

Orion is also home to another famous nebula: the Horsehead. Shaped like its namesake, the Horsehead Nebula is silhouetted against a glowing cloud of gas below Alnitak, the farthest left of the three stars in Orion’s belt. It is best seen in images online.

In the predawn sky, the sinuous form of the summer constellation Scorpius rears up over the southeastern horizon. On the 6th, a hefty waning crescent moon hangs near Antares, the red heart of the scorpion.

Groundhog Day also carries the promise of summer. It began as the astronomically based Celtic holiday Imbolc, which heralded the start of lambing season. Imbolc was one of four “cross-quarter” days falling midway between a solstice and an equinox.

A waxing moon shines close to Mars on the evening of the 18th. On the night of the 26th-27th, February’s full moon crosses the sky with the spring constellation Leo, the lion.

JANUARY 2021

Minnesota Starwatch: Spica, Corvus, and the waning Moon as seen facing south at predawn on January 7th.

As the new year dawns, three of the five brightest planets are busy dropping out of view—Venus from its position as a morning planet, Jupiter and Saturn as ornaments of the evening sky.

Actually, the planets are only switching places. We’re leaving Jupiter and Saturn in the dust as we circle behind the sun, but when we come around in a couple of months we’ll find them in the morning sky. Likewise, speedy Venus is now heading behind the sun, but it will reappear as an evening planet in late spring.

In the last two weeks of January, Mercury pops up very low in the west-southwest. The sunset glow may obscure it, so have your binoculars handy. Mars, however, remains high but drifts slowly westward as the large knot of famous winter constellations closes in on it from the east.

These constellations won’t all be up until about three hours after sunset on the 1st, earlier as the month goes on. Atop the assembly sits brilliant Capella, in Auriga, the charioteer. At the bottom, even more brilliant Sirius outshines not only its fellow stars in Canis Major, the big dog, but every other star in the night sky. Sirius also is one point of the nearly equilateral Winter Triangle. The others are Betelgeuse, at Orion’s right shoulder, and Procyon, to the upper left of Sirius in Canis Minor, the little dog.

The morning of the 2nd, Earth reaches perihelion, its minimum distance—about 91.5 million miles—from the sun. We sweep through perihelion at top speed: 18.8 miles per second.

On the 6th, a last-quarter moon hovers above Spica, the only bright star in Virgo, the maiden, in the predawn sky. The next morning, the moon appears next to Spica. Off to Spica’s lower right is the skewed four-sided figure of Corvus, the crow. High to the left of Spica blazes Arcturus, the beacon of kite-shaped Bootes, the herdsman. An old moon rises near Antares, the heart of Scorpius, the morning of the 10th. If you go out 40 minutes before sunrise on the 11th, you may catch a very thin lunar crescent close to Venus.

January’s full moon shines the night of the 28th and follows the winter constellations across the sky.