Northern Sky

Northern Sky  –  May 26 – June 8, 2018
 
May closes out--almost--with another full moon, the full flower moon. The moment of fullness arrives at 9:19 a.m. on Tuesday, the 29th. But by then the moon will already have set, so if you want to see it, go outside at sunrise. It'll be over in the west, looking pretty against a pale sky.
 
If you're up even earlier that day, say, 90 minutes before sunrise, you'll have a great view of stars and planets. Like Jupiter getting ready to set in the west. Or the moon right above the crown of Scorpius, a more or less vertical curved line of three stars very low in the southwest. Just southeast of the moon you'll see the scorpion’s red heart, Antares, the rival of Mars. East of the moon are two bright objects. One is Saturn. It's just above the Teapot of Sagittarius, a lovely star pattern that actually looks like a teapot. These mornings it tips its spout as if to pour tea on the stinger of the scorpion. Earth is catching up to Saturn in the orbital race, and on June 27, we lap the ringed planet, and it'll be at its brightest.
 
The other bright object is farther east, and that's Mars. Mars is already starting to dazzle us with its growing brilliance. That's because, as I've been saying, it, too, is going to get lapped by Earth soon. At the end of July, in fact--just a month after Saturn. Above Mars, the Summer Triangle of bright stars twinkles away. And, wouldn't you know it, gaining altitude in the east is the Great Square of Pegasus, an autumn constellation.
 
After full moon, the moon continues its way eastward. On June 1, it'll be between Saturn and the Teaspoon, a curved line of stars hanging down over the handle of the Teapot. On the 2nd it'll be between Saturn and Mars, and on the morning of the 3rd it hovers over Mars; these two objects will look like a big pearl above a small ruby. After passing Mars, the moon glides through a relatively dim starfield on its way to becoming new.
 
In the evening sky, we have Jupiter again. It's up in the southeast by nightfall, very bright but no match for Venus. The planets I mentioned earlier follow Jupiter into the sky, but not all of them make it during the evening—that is, pre-midnight—hours. As for Venus, it continues to blaze away in the west. During the first week of June the Gemini twins Pollux and Castor drop toward the planet. The brighter twin, Pollux, is the one closer to Venus. During the last several days of May and into June, the twins and Venus form a triangle that starts out long and thin but then shortens and flattens as these three objects shift positions. By Friday, June 8, they'll have formed one of the flattest triangles in history. The twins are among the last of the winter stars to head into the sunset, but they'll all reappear in the morning sky by late summer.
 
Turning a little to the north from Venus, you may see Capella, a gorgeous multicolored winter star. It's the brightest in Auriga, the charioteer, but with so many bright stars up in the winter, it may get kind of lost in the shuffle.
 
Also after nightfall, we have Spica, in Virgo, the next bright object west of Jupiter. If skies are dark, you might want to grab a star chart and try to trace the form of Virgo. Spica is the constellation's only bright star, so it can be a challenge to find Virgo the first time.
 

Northern Sky -  by Deane Morrison - May 12-25 2018
 
 
For a week starting Saturday, May 12, we have morning and evening skies that are free or nearly free of moonlight, and that makes for good starwatching. The moon becomes new in the early morning of the 15th, then starts its next march eastward across the evening sky. As it goes, it gets bigger and brighter and sets later, so we have less and less time to see celestial objects without the moon washing everything out.
 
On evenings around new moon, look for Leo, the lion, high in the southwest. Its most prominent feature is a backward question mark of stars, known as the Sickle. The dot of the question mark is Regulus, the brightest star in Leo. Regulus is also the sharp point of a stellar triangle; the other two stars are brilliant Arcturus, which is high in the south at nightfall, and Spica, which is below Arcturus. Arcturus is the anchor for the kite-shaped constellation Bootes, the herdsman, and Spica is the only bright star in Virgo. These days Spica and Arcturus are also part of another triangle, with Jupiter. Jupiter is a beacon in the east, near the peak of its brightness. Also, just to the southwest of Spica you’ll find a four-sided figure. This is Corvus, the crow—another of those constellations that aren’t very prominent but can be fun to find.
 
On Wednesday, the 16th, look for a very young crescent moon down by the horizon below Venus—that brilliant light in the west. The next night, the 17th, the waxing moon will have moved to about the same level as Venus. On the 18th, a fatter crescent appears below Pollux, the brighter of the Gemini twins. The other twin, Castor, is to the right of Pollux. On Monday the 21st, a first-quarter moon will be practically sitting on top of Regulus. And the evening of the 25th, a bigger, brighter moon appears above Spica.
 
If you have a lawn chair, you may want to grab it and look for Ursa Major, the great bear. It’s really high after nightfall these days, close to the overhead position, hence the advisability of observing from a reclining position. You may also need a star chart to make out the whole constellation. The Big Dipper is the bear’s hindquarters and tail, and the arc of the tail—which is also the handle of the dipper—leads you to Arcturus. Just remember “arc to Arcturus.” At the bend of the handle is a famous double star. Binoculars will bring them out nicely. The stars are Mizar, the brighter one, and Alcor, its fainter companion. These two have also been dubbed the horse and rider.
 
Also, I enjoy looking for three tight pairs of stars that represent the paws and one hind foot of the great bear—although not all star maps indicate that. The three pairs of stars form a diagonal line below the bowl of the Big Dipper and they have been named the Three Leaps of the Gazelle. They’re also not prominent, but they’re one—or three—more things that can be fun to find.
 
In astronomy news, NASA just launched its InSight mission to Mars. InSight is designed to find out, as NASA puts it, “what makes Mars tick.” The lander will plant a seismometer on Mars. It’ll study Mars quakes, and the mission will also track how heat in the interior of the planet gets dispersed, and how Mars wobbles. It may even be able to detect liquid water or plumes of active volcanoes below the Martian surface. All this data will shed light on the formation of other rocky planets, including Earth and the moon. Landing is scheduled for November 26th.

Northern Sky by Deane Morrison for April 28 - May 10 2018

April's weather has been forgettable, but on the evening of the 29th it gives us a gorgeous full moon. Perfect fullness happens at 7:58. That's just minutes after moonrise in Grand Marais, so when it first clears the eastern horizon it'll be one of the roundest moons ever. April's full moon is called the full pink moon, after wild ground phlox, also known as grass pink, a small pink flower that carpets the land this time of year. This full moon won't be especially large or small, but if you can get outside just before eight o'clock on Sunday, the 29th, it will be worth it.
 
The next night is a treat for anybody who follows the Celtic holidays. It's April 30, the eve of May Day. According to old Celtic tradition, sundown on April 30 was the beginning of the holiday known as Beltane. It signified the end of the dark half of the year, which began at sundown on Halloween. The critical events that defined the dark and light halves of the old Celtic year had to do with evil spirits. At sundown on Halloween, they came rushing out of exile and started causing illness and otherwise making trouble, but at sunrise on May 1 they disappeared into exile again, and the light half of the year began. Beltane, or May Day, and Halloween are astronomically based holidays. They're what's known as cross-quarter days and they fall more or less halfway between an equinox and a solstice. Groundhog Day is another one, but the fourth cross-quarter day doesn’t get much press. That’s Lughnasa, a harvest holiday at the beginning of August.
 
As we get into May, the moon will be waning and spending less time in the evening sky. Be sure to have a look at Venus; it's the bright object that comes out in the afterglow of the setting sun. In the east, Jupiter is a rival beacon. These are the two brightest planets, and when darkness falls you can compare them not just in brightness but in color. On the night of the full moon, Jupiter rises below the moon and follows it across the sky.
 
Jupiter is about as bright as it gets now because Earth laps it in the orbital race early on the night of May 8th. That event is called opposition because it puts Jupiter opposite the sun in the sky. At opposition an outer planet rises around sunset and sets around sunrise. On the 10th, Jupiter and Earth come within about 409 million miles. That's their closest approach, and it comes after opposition because Earth is moving farther from the sun while Jupiter is moving in, and that brings them closer before speedier Earth pulls away.
 
For early risers, we still have, in this order, Mars, Saturn and Jupiter strung from left to right across the predawn sky in the south. This string of planets is lengthening as Mars moves eastward against the background of stars while Saturn and Jupiter move westward. Saturn and Jupiter appear to move westward against the stars, in what's called retrograde motion, now because they’re at or nearing opposition. When Earth is lapping one of the outer planets, the act of passing it by makes it appear to move backwards, or westward, even though the planet’s own motion carries it eastward. It's the same when a runner in an inside lane laps a runner in an outer lane. The outer runner will seem to move in the opposite direction from how he or she is actually moving. Saturn reaches opposition in late June, Mars not till late July.
 

Northern Sky by Deane Morrison for  April 14-27 2018
 
If April can just let up on the rain and snow a bit, there are bright planets in both morning and evening for us to enjoy.
 
In the evening, we have Venus, the brightest of planets. It’s hard to miss—a real beacon in the west after sunset. But its beauty obscures a rather different reality. Venus has a thick atmosphere that’s mostly carbon dioxide. The planet owes its brightness to very reflective clouds of sulfuric acid droplets and crystals. Its surface atmospheric pressure is more than 90 times that of Earth’—as high as the pressure 3,000 feet down in the ocean. And its surface temperature hovers above 850 degrees Fahrenheit. In short, Venus is a hellish place with a heavenly face.
 
For an even more heavenly sight, have a look on Tuesday, April 17, when the moon pays a visit. On that evening Venus and a young fingernail crescent moon will make a lovely pair.
 
If you go outside on or before the 17th, before the moon gets bright enough to interfere, try comparing Venus to Sirius, the brightest of stars, which will be rather low in the southwest. Spoiler alert: It's no contest; Venus easily outshines Sirius.
 
Sirius and the other winter stars are busy exiting the sky to the west. In their place is the spring constellation Leo the lion. It’s now high in the south during prime evening viewing hours. Look for a backward question mark of stars with a bright one--namely, Regulus--at the base. That question mark is known as the Sickle, and its stars represent Leo's head and heart. The hindquarters and tail are a triangle of stars just east of the Sickle.
 
In the morning sky, the best thing to see is Mars because it's getting really bright now as Earth gets closer and closer. It appears as a red dot low in the southeast for a couple of hours before dawn. West of Mars is Saturn, and even farther west is brilliant Jupiter.
 
In astronomy news, a University of Minnesota researcher--formerly at UC Berkeley--led a team that found the most distant individual star ever observed. Its light took nine billion years to reach Earth--or, more exactly, the Hubble Space Telescope. It's a large blue star, but it could never have been seen from, as NASA puts it, more than halfway across the universe if nature hadn't given us a cosmic magnifying glass. That magnifying glass is a cluster of galaxies that are between us and the star, which the team named Icarus.
 
It works like this. Massive objects like stars, galaxies, and clusters of galaxies act like lenses. Their gravity is so strong, it bends the space all around them, and light bends with it. Icarus is behind that cluster of galaxies, but when light from the star got near the cluster, it was bent by the cluster's gravity and curved around the cluster, then continued on toward us. The bending focused and magnified Icarus’s light by about 600 times. But that wasn't enough; the researchers hypothesize that Icarus only became visible—briefly—when a sun-sized star in the cluster of galaxies moved in front of Icarus. Then, that star took the light from Icarus-- already magnified 600 times--and focused it again, resulting in a total magnification of 2,000 times. Enough for Hubble to pick up. This work gives astronomers a way to study stars in very distant galaxies. We see them as they existed billions of years ago, when the universe was much younger.
 
The team named the star Icarus because it had a brief, you might say, moment in the sun, just like its namesake from Greek mythology. He made wings of feathers, held together with wax, but he flew too near the sun. The wax melted, and that was it for Icarus.  
 

Northern Sky - by Deane Morrison for March 31 - April 13, 2018.

Deane Morrison is a science writer at the University of Minnesota.
She authors the Minnesota Starwatch column.  It can be found on the University of Minnesota website at 
astro.umn.edu.

Northern Sky by Deane Morrison -  March 17-30 2018

March came in with a full moon, and it's going out with a full moon. Meanwhile, there's plenty going on in both the morning and evening skies.
 
Look to the south an hour before dawn and you'll see Jupiter blazing away. Then look eastward to see the stars of Scorpius, especially bright red Antares, the heart of the scorpion. Moving east again, we have the Teapot of Sagittarius. Right above the Teapot, Saturn seems to float motionless from day to day. But Mars is moving eastward against the background of stars, and it's rapidly closing in on Saturn. Mars stays to the west of Saturn until the end of March, but in the first week of April it's going to zip right below the ringed planet.
 
If you look above and east of Saturn and Mars, you'll see the Summer Triangle of bright stars high in the southeast. And off to the west of Jupiter, and higher, we have Arcturus, the brightest star in the northern hemisphere of sky. If you're ever in doubt as to which star is Arcturus, you can find it by extending the curve of the Big Dipper's handle.
 
In the evening sky, Venus is low in the west after sunset. So is Mercury, but not for long. The best night to see it was March 15. But now it's fading and dropping toward the sun because it's on its way between Earth and the sun. On the 17th Mercury is to the upper right of Venus, which is by far the brighter planet. On the 18th, a young crescent moon appears with the two planets--that will be lovely. But by the 21st Mercury will have dropped down to the level of Venus, and then it just plummets out of sight.
 
Sirius, the brightest star in the night sky, is still up. It's somewhat low in the south to southwest after nightfall. If you've never seen it, do take a look. And while you're at it, grab some binoculars and look for the Beehive star cluster, an inconspicuous little jewel that is now high in the south.
 
The Beehive is between two bright stars. One star is Pollux, the brighter of the Gemini twins. To find it, start with Sirius and look up to the bright star Procyon, and then up about the same distance again. The other star is Regulus, the brightest in Leo, the lion. It's east and a little south of Pollux. The Beehive is a bit dim, so you may need a star chart to get its exact location. But seeing it through binoculars is a real treat.
 
The spring equinox arrives at 11:15 a.m. on Tuesday, March 20. At that instant, Earth will be lighted from pole to pole and it won't be tilted with respect to the sun. That's because our spring equinox is an inflection point, the point at which the Earth’s orientation to the sun switches so that the Northern Hemisphere starts tilting toward the sun. The tilt changes fastest in the days closest to the equinoxes; therefore, these days we're gaining daylight at the maximum rate, approximately three minutes a day. Also, starting at the spring equinox, days get longer as you travel north.
 
March gets its second full moon on the 31st. This qualifies as another blue moon. The moment of fullness comes at 7:37 a.m. However, the moon sets over Grand Marais at 7:10 that morning. If you want to see the moon at its fullest, you might want to get outside by 6:30, or even earlier if there are obstructions to your view of the western horizon. Or just enjoy it the evening of the 30th.
 

Northern Sky -  March 3-16 2018

During the first half of March, the moon wanes away to the thinnest of crescents and then to a new moon on the morning of the 17th. In the process, the moon moves across the morning sky and gives us more moon-free time to enjoy the evening sky. 
 
These days we can see Venus and Mercury together above the sunset horizon. Mercury is the closest planet to the sun, and so it never appears very far from the sun, and the sun’s glare often makes it hard to catch Mercury. To see Mercury and Venus, look low in the west shortly after sunset—maybe 30 minutes after. Venus is by far the brighter planet, so it's easy to tell the two apart. Mercury climbs up and passes closest to Venus on the 3rd, when the planets will be about two moon widths apart. Mercury gets higher until the 15th, when it will be at its greatest angular distance from the sun, and then it rapidly falls into the sunset. Whenever Mercury or Venus falls into a setting sun, that's the beginning of the planet’s next trip between Earth and the sun. When it emerges from that trip it reappears in the morning sky.
 
Mercury was, of course, the messenger of the gods. And it's easy to see how it got that name. From our point of view, it's always racing back and forth between the evening and morning sky, never sticking around for very long. As for Venus, right now it’s also climbing in the evening twilight, but slowly, and it will stick around for several more months.
 
If you're out after the sky gets good and dark, enjoy the bright winter stars in the south and southwest. Next month they'll begin setting in the early evening.
 
In the morning sky, the predawn sky, we have the three outer planets that are visible to the naked eye lined up in the southeast and south. From left to right they are Saturn, Mars and Jupiter. Between Mars and Jupiter is Antares, a gigantic red star that marks the heart of Scorpius. But the real star of the show is Mars. If you can get out and watch every day, or every other day, you can see it moving eastward against the background of stars, away from Antares and Jupiter, and toward Saturn.
 
Starting on the 7th, that waning moon I mentioned comes in handy for telling all these objects apart. As it wanes, the moon sweeps from east to west across the morning sky. On the 7th, the moon is close to Jupiter. On the 8th, it appears above Antares. On the 9th, it's approaching Mars, and on the 10th, it's passed Mars and sits between Mars and Saturn. And on the 11th it has passed Saturn and appears near the bowl of the Teaspoon, which is a curved line of stars above the handle of the Teapot of Sagittarius. Over the next few mornings, the moon will be thinner and closer to the sun, and that may make it an even nicer companion to the planets and stars.
 
The Summer Triangle of bright stars is also up, high in the east, before dawn. And high in the south to southwest is Arcturus, the brightest star in Bootes, the herdsman, a lovely kite-shaped constellation.
 
With the moon mostly absent from the early evening sky, we have another chance to find the elusive zodiacal light an hour or so after sunset. It appears as a faint finger of light pointing up along the sun's path. The zodiacal light is the result of sunlight reflecting off dust in the plane of the solar system.
 
 

“Northern Sky” by Deane Morrison  Feb. 17-March 2 2018

In the second half of February, Venus starts to peek out from the sun's afterglow and slowly climb into the evening sky. On Saturday, February 17, there's a thin young crescent moon in the west-southwest, and if you look half an hour after sunset you may spot Venus way below and a little to the right of the moon. In the coming days, the moon will move on to the east, but keep looking in the same spot for Venus, although it will be a little higher each night.
 
As the moon makes its way eastward, it waxes. Between the evenings of the 22nd and 23rd, it passes the bright star Aldebaran, the eye of Taurus, the bull. The evening of the 24th, it travels the night sky above Orion.
 
The moon finally becomes full on Thursday, March 1st, at 6:51 p.m. It'll be big and bright because it'll be just a couple of days past its closest approach to Earth in this lunar cycle. And, since moonrise over Grand Marais comes at 5:32 p.m.--barely more than an hour before perfect fullness--it'll be one of the roundest moons. Also, this gorgeous moon rises against a pale sky opposite a setting sun. It crosses the night sky below the belly of Leo, the lion, a spring constellation.
 
The latter half of February is a good time to watch the predawn show because there’s little interference from the moon. Three planets are all well up by an hour before sunrise, and they form an almost perfectly straight line. Starting low in the southeast and moving diagonally up and to the right, they are Saturn, Mars and Jupiter. Off to the right of Mars is Antares, the bright heart of Scorpius. Antares' name means rival of Mars, and as Mars brightens over the coming months it'll really outshine Antares and even begin to rival Jupiter.
 
Unlike Mars, Jupiter and Saturn don't change much in brightness because they're always very far from Earth no matter where Earth is in its orbit. Therefore, their distance from us can only change by a relatively small amount. But the orbits of Mars and Earth are much closer, and like runners in adjacent lanes on a track, our two planets vary widely in relative distance. As Earth gains on Mars and gets ready to lap it in the race around the sun, we get a lot closer. Mars’s mid-February distance is about 143 million miles; that shrinks to only 36 million miles when we lap it in July.
 
Mars also differs from Saturn and Jupiter in another way that we don’t need a telescope to see. If you watch the planets’ positions with respect to the stars, it looks as though Saturn and Jupiter are barely budging. And why not? Earth’s orbital motion pushes both stars and planets westward. But Mars is budging quite a bit compared to the background of stars, because its orbital motion, eastward, is so much faster than the other outer planets'. Sure, Earth’s motion also pushes Mars westward, but not nearly as fast as it does the background stars, or Jupiter or Saturn. From morning to morning you can watch Mars plowing its way eastward, away from Jupiter and Antares and toward Saturn. In the first week of April, Mars passes Saturn.
 
Also in the predawn sky, the Big Dipper is now hanging high in the west. If you follow the curve of its handle, that brings you to Arcturus, whose name means follower or guardian of the bear. Arcturus is a brilliant star, high to the upper right of Jupiter. Also try finding the crown of Scorpius, which is three stars that now look like a shield protecting Antares from Jupiter.
 

Northern Sky  by  Deane Morrison 
Feb. 3-16 2018
 
As we approach the middle of February, the moon spends more and more time in the morning sky, and that's good for everybody who would rather see stars in the evening.
 
This is the best time of year to enjoy all the bright winter constellations I've been talking about. If you go out an hour after sunset, you'll see them in the southeast to south. Sirius is the brightest star of all, and it's also the lowest of the bright winter stars. Sirius is called the Dog Star because it dominates Canis Major, the larger of Orion's hunting dogs. In ancient times, people thought that during the summer, when Sirius appears nearer the sun in the sky, its heat combined with the sun's heat to produce the hottest days of the year, which were dubbed the dog days. Of course, Sirius has nothing to do with it, but when looking at it against a dark winter sky, it's easy to see how people could think that.
 
Sirius is also part of two well-known geometric arrangements of stars. One is the Winter Triangle. Besides Sirius, the stars in the triangle are Procyon, which is above and a little east of Sirius, and reddish Betelgeuse, which is a little west of Procyon. Then there's the Winter Hexagon. Again starting with Sirius, move around clockwise to Procyon, which is in Canis Minor, the little dog; then Pollux, the brighter Gemini twin; Capella, in Bootes the herdsman--this is the highest star in the hexagon; then Aldebaran, the eye of Taurus, the bull; and finally Rigel, in Orion.
 
In the morning sky, the planet show continues. The planets and neighboring stars are moving out of the southeast and into the south now. All three morning planets are rather low, but the highest, brightest and most western one is Jupiter. Moving to the left, or east, the constellation Scorpius has Mars, and below Mars is the gigantic red star Antares, the heart of the scorpion. The bright light to the lower left of Mars and Antares is Saturn. At this point, Mars isn’t especially bright, because it’s about 143 million miles away. But when Earth catches up to it this summer, it’ll be almost four times closer—just 36 million miles away. And pretty darn bright.
 
The moon wanes away to the new phase on February 15th, and on its way it visits the morning planets. Between the 7th and 8th it sweeps by Jupiter. Between the 8th and 9th, it passes Mars. On the 9th, the moon, Mars and Antares will make a nice trio of objects. On the 11th, the moon will be right above Saturn, and Saturn will be right above the lid of the Teapot of Sagittarius. On the 12th, the crescent moon will be sitting in the curved line of stars known as the Teaspoon, which hangs above the handle of the Teapot. On the 13th, the moon will be a lovely thin crescent. On the 16th, a young moon of the next cycle appears in the west, in the sun's afterglow. You'll have to look about half an hour after sunset to see it, and you may catch Venus to the lower right of the moon. This month, Venus is just starting a climb into the evening sky.
 
Also in the evening, look for the pale and elusive zodiacal light in the west as soon as the sky gets dark. The zodiacal light appears as a broad finger, or cone, of light extending up along the sun's path. It's caused by sunlight reflecting off dust in the plane of the solar system. You need dark skies to see it, and if you do, count yourself among the fortunate few.

 

Northern Sky by Deane Morrison  for January 20 through February 2, 2018.

Deane Morrison is a science writer at the University of Minnesota.
 She authors the Minnesota Starwatch column, and in this feature
she shares what there is to see in the night sky in our region.

Deane Morrison’s column “Minnesota Starwatch” can be found on the
University of Minnesota website at     astro.umn.edu.