Canis Minor the Lesser or Little Dog is a small constellation, but it has a major star. It’s home to the 8th-brightest star in all the sky, called Procyon or Alpha Canis Minoris. This star is also one of the six stars in the noticeable Winter Circle asterism.

The companion constellation to the Lesser Dog is, of course, nearby Canis Major, the Greater Dog. And Canis Major houses the brightest star in the sky, Sirius, which is also part of the Winter Circle.

Sirius is often called the Dog Star. And Procyon is known as the Little Dog Star.

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The mythology of Canis Minor

Canis Minor and Canis Major are the faithful dogs of Orion the Hunter. They lie east of Orion and follow him up from the horizon in the Northern Hemisphere.

In one mythological story, the gods placed the Lesser Dog at the banks of the river of the Milky Way so it would never be thirsty.

English astronomer Richard Proctor tried to rename Canis Minor for a cat, Felis, to distinguish it from Canis Major.

Due to Canis Minor’s proximity to Monoceros the Unicorn, many illustrations depict the Lesser Dog so that is seems to be standing on the Unicorn’s back.

Finding the Lesser Dog

Canis Minor is easy to find in February and March. If you can find Orion, you can easily starhop your way to Canis Minor. If you’re in the Northern Hemisphere, Orion stands high above the southern horizon mid-evening. To its left, out from reddish Betelgeuse, is bright Procyon. You can spot even brighter Sirius to the lower right. These three stars make up the Winter Triangle.

From the Southern Hemisphere, Orion is standing on his head above the northern horizon and Canis Minor is to the right.

Stars of Canis Minor

While Canis Minor is not the smallest of the 88 constellations, it is one of the smaller ones, ranking 71st. The majority of the smallest constellations are in Southern Hemisphere skies.

This diminutive constellation has two stars of note. The first you’ve already met, Procyon, or the Little Dog Star, shines at magnitude 0.40. The temperature of Procyon – at 7,000 kelvin (6,700 Celsius or 12,000 Fahrenheit) – is similar to that of the sun. But unlike the sun, it has a stellar companion, a hard-to-see white dwarf which requires a large telescope. Procyon appears bright to us on Earth because it’s a mere 11.4 light-years away.

The other bright star in Canis Minor is Gomeisa, or Beta Canis Minoris. Gomeisa shines at a magnitude 2.89. Gomeisa lies a much more distant 170 light-years away.

Part of the Winter Triangle and Circle

Bright Procyon gets incorporated into two important winter asterisms: the Winter Triangle and Winter Circle or Hexagon. Starting at the bottom of the Winter Circle with the brightest star, Sirius, the other stars in the Circle are Procyon, Pollux (and it twin, Castor), Capella, Aldebaran and Rigel. The Winter Triangle is like a slice of a pie taken out of the Winter Circle. It includes Sirius and Procyon plus Orion’s reddish Betelgeuse.

Deep-sky targets in Canis Minor

Also, a number of galaxies and nebulae lie in Canis Minor, but the majority are too faint for the casual amateur astronomer. In fact, the brightest of these is only 13th magnitude, the spiral galaxy NGC 2485. Because our own Milky Way lies in the southwest portion of the constellation, the faint galaxies that you will find all lie in the northeast portion of Canis Minor’s boundaries. You can think of the line drawn between Procyon and Gomeisa as the border of the Milky Way.

Bottom line: Canis Minor is a small constellation with one notably bright star, Procyon. The constellation of the Lesser Dog follows Orion across the sky.

The post Meet Canis Minor the Lesser Dog in February first appeared on EarthSky.

Taurus the Bull

The constellation Taurus the Bull is visible during the fall through spring in the Northern Hemisphere (or spring through fall in the Southern Hemisphere). It sits in the evening sky close to the easy-to-see constellation Orion.

Basically, Taurus the Bull takes the shape of a two-pronged fork, with the center V-shape consisting of an actual star cluster – a family of stars in space – that we call the Hyades. The Hyades marks the face of the Bull. The bright red star Aldebaran shines in the V and represents the Bull’s fiery eye. In addition, Taurus holds another famous star cluster, which we call the Pleiades or Seven Sisters. You’ll notice it has the shape of a tiny dipper.

Moreover, Taurus is also the radiant point for the annual Taurid meteor shower, which happens every year in November.

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Locating Taurus the Bull

Taurus is a constellation of the zodiac, which means the sun, moon and planets travel through it regularly. In fact, the sun passes through the constellation Taurus from about May 14 to June 21. However, you can’t see Taurus when the sun is within its borders.

Generally speaking, Taurus is easy to find on its own. That’s because of the two star clusters, the V-shaped Hyades and small but distinctive stars of the Pleiades. Also, if you orient yourself with the famous constellation of Orion, you’ll know you’re looking in the right place.

First find Orion by looking for its three Belt stars. Orion and Taurus are next-door neighbors on the sky’s dome. In fact, Taurus rises above the horizon first. So by the time Orion is risen, you can use its Belt stars to draw a line upward to find Aldebaran and the two clusters of Taurus.

The stars of the Bull

Furthermore, Taurus is home to two particularly bright stars: Aldebaran and Elnath. Aldebaran is the easier of the two to find because it’s brighter, it’s part of the V-shape of the Hyades and it has a reddish hue.

For good reason, stargazers think of Aldebaran as the Bull’s fiery eye. Aldebaran is the 14th brightest star in the sky. It shines at magnitude 0.85. Although it may look like part of the Hyades cluster, it’s much closer. Aldebaran lies 65 light-years distant. The other stars of the Hyades are about 150 light-years away.

Elnath marks the end of one of Taurus the Bull’s horns. It’s on the opposite side of the Bull’s head from Aldebaran. Elnath is the 2nd brightest star in Taurus after Aldebaran. It shines at magnitude 1.68. Relatively nearby, Elnath lies about 130 light-years away, in the direction of the Milky Way’s anticenter.

The Crab Nebula

In addition, Taurus holds an excellent deep-sky target that you can spot with binoculars or a small telescope. Messier 1, or the Crab Nebula, is what’s left of a star after it exploded in a supernova. As a result, it lit up the daytime sky for over a month in 1054 CE.

Now, the Crab Nebula shines at magnitude 8.4. Plus, it’s easy to find since it lies near a star in Taurus named Zeta Tauri. While Elnath is the point of one of the Bull’s Horns, Zeta Tauri is the other.

Taurus the Bull in mythology and timekeeping

According to Greek mythology, the constellation Taurus commemorates the god Zeus. That’s because Zeus changed himself into a beautiful white Bull to win the affections of the Phoenician princess Europa. After Europa hopped onto the Bull’s back, the Bull swam across the Mediterranean Sea, taking Europa all the way to the island of Crete. Later, Zeus and Europa became the parents of Minos, the legendary king of Crete.

Meanwhile, the Zuni of New Mexico used the Pleiades cluster as an agricultural calendar. When the Pleiades – which the Zuni called the Seed Stars – disappeared into the western dusk in spring, they knew it was safe to plant their seeds, as the danger of frost had passed. However, the Zuni also knew the planting must be done before the Pleiades reappeared in the east before sunrise. Otherwise, immature plants would succumb to autumn frosts.

And the Zuni were hardly alone in their reverence for the Pleiades star cluster. Indeed, probably no other star formation has enjoyed such worldwide renown for timekeeping, celebration and storytelling.

Bottom line: Taurus the Bull resides near the constellation Orion. It contains two famous star clusters that are easy to spot: the Pleiades and the Hyades.

The constellations of the zodiac

Taurus the Bull in the evening sky
Gemini the Twins, home to 2 bright stars
Cancer the Crab and its Beehive Cluster
Leo the Lion and its backward question mark
Virgo the Maiden in northern spring skies
Libra the Scales, a zodiacal constellation
Scorpius the Scorpion is a summertime delight
Sagittarius the Archer and its famous Teapot
Capricornus the Sea-goat has an arrowhead shape
Aquarius the Water Bearer and its stars
Pisces the Fish, 1st constellation of the zodiac
Say hello to Aries the Ram
Born under the sign of Ophiuchus?

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You can find a Unicorn in the night sky. Monoceros the Unicorn is a constellation that Dutch cartographer Petrus Plancius invented in the 1600s. And, in January and February, the Unicorn is in a good position for viewing in the evening sky. It’s highest up and easiest to see in the late evening hours. And it’s visible nearly all night, with one caveat. That is – if you want to capture the celestial Unicorn – be sure to look in a dark sky. That’s because, true to mythical unicorns, Monoceros is elusive!

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How to find Monoceros

In January and February, the Unicorn comes out at nightfall. First, focus in on the bright stars Betelgeuse, Sirius and Procyon (see charts on this page). They make a triangle, which – in the Northern Hemisphere – has the nickname of the Winter Triangle. But you can see these stars from the Southern Hemisphere, too. In fact, Orion the Hunter and the stars near it are even better placed for viewing from the southern part of Earth’s globe.

Within the triangle of stars made by Betelgeuse, Sirius and Procyon – hidden among the many bright and glittering stars and constellations visible at this time of year – there’s a constellation that’s as elusive in our night sky as its namesake is in countless fairy tales.

This is the constellation Monoceros the Unicorn.

Star clusters in the Unicorn

The winter Milky Way runs through Monoceros. Those with dark skies might try drawing an imaginary line from the star Sirius to Procyon. About a third of the way along this line, you’ll find a hazy object. You can spot this region with optical aid; something will pop out at you. It’s a star cluster called M50. In fact, it’s one of several open star clusters in the region.

You need a telescope to see M50 clearly. But, with an ordinary pair of binoculars, this cluster of stars is wonderful to glimpse and contemplate on a winter night. There are about 100 stars in the little patch we know as M50. Also, the main part of the cluster is about 10 light-years across. The entire cluster is located some 3,000 light-years from us.

Bottom line: Treat yourself to a visit with a mythical beast – Monoceros the Unicorn – in the January and February evening sky.

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South circumpolar constellations are those that can be seen any time of year for observers in the Southern Hemisphere. Dorado the Swordfish and Mensa the Table Mountain are two of these. They hold the important distinction of being home to the Large Magellanic Cloud, a satellite galaxy of the Milky Way which flows across the border from one constellation to the other.

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The constellation Dorado the Swordfish

Dorado is a constellation in Southern Hemisphere skies that variously has the nickname of Swordfish, Dolphinfish and Goldfish. The two brightest stars of Dorado are actually somewhat dim. Alpha Doradus is magnitude 3.30, and Beta Doradus is magnitude 3.76. Still, you should be able to see these stars from a city without too much light pollution.

You’ll definitely want a dark sky, however, when it’s time to spot the most important feature of Dorado: the Large Magellanic Cloud. Dorado holds the larger portion of this satellite galaxy that it shares with Mensa. While you can see the Large Magellanic Cloud without optical aid, a telescope will let you explore many more of its clusters and nebulae.

Inside the Large Magellanic Cloud on Dorado’s side of the border is a popular nebula: the Tarantula Nebula, NGC 2070. The Tarantula Nebula shines at magnitude 8.19. It’s remarkable that we can see this cloud of gas and dust from another galaxy that’s around 160,000 light-years away. It’s the largest known nebula where new stars are being born. The Tarantula Nebula is an emission nebula, the same type of nebula as the Orion Nebula, M42. If the Tarantula Nebula were the same distance from Earth as the Orion Nebula, it would appear as large as all of the constellation Orion.

The constellation Mensa the Table Mountain

French astronomer Nicolas-Louis de Lacaille named Mensa the Table Mountain for Table Mountain in South Africa. Dorado borders Mensa on one side, and Octans – the constellation that contains the south celestial pole – lies on its opposite side.

Mensa’s stars are so dim that its brightest is the magnitude 5.1 star Alpha Mensae. In fact, no other constellation has a dimmer “brightest” star than Mensa. So of all the 88 constellations, Mensa could be considered the dimmest.

Even though Mensa contains nearly half of the Large Magellanic Cloud, most of the constellation’s star clusters, both open and globular, are rather dim. One unusual star, a luminous blue variable that scientists named R71, is normally an 11th magnitude star except during outbursts. In the 1970s it had regular outbursts, raising its magnitude temporarily to 9.2. Then, in 2012, it brightened to more than a million times as luminous as the sun. But even then, with its great distance, its peak magnitude was just 8.7, which you’d still have needed a telescope to see. Faintness is Mensa’s claim to fame.

The Large Magellanic Cloud

The Large Magellanic Cloud lies in both the constellations Dorado and Mensa. Draw a line from Sirius past the right side of Canopus to find it.

The Large Magellanic Cloud shines at magnitude 0.9. Keep in mind that it’s stretched out over an area of sky about 9 by 11 degrees. A star of that magnitude would appear very bright because of its pinpoint source of light, but for the Large Magellanic Cloud, its diffuse, spread-out light means it appears as a hazy smudge on the sky.

The famous Supernova 1987A exploded in the Large Magellanic Cloud on the Dorado side of the border. After it lit up overnight from February 23 to 24, 1987, people continued to see the supernova with the unaided eye for months. In fact, it didn’t peak in brightness until May. It was the brightest supernova visible in 400 years.

Bottom line: The constellations Dorado and Mensa are deep in southern skies. Between them, stretching across the border, lies the Large Magellanic Cloud.

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Lepus the Hare is a constellation that brushes the southern horizon in winter months for observers at high latitudes in the Northern Hemisphere. The Hare is under the feet of Orion the Hunter and beside Orion’s hunting dog, Canis Major. Lepus will move from the southeast to the southwest over the course of each winter night and during the winter season. Meanwhile, for Southern Hemisphere observers, Lepus cuts across the sky in an arc that passes nearly overhead in January.

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The mythology of Lepus

Lepus the Hare is a constellation known since ancient times. Some myths say that nearby Canis Major the Greater Dog pursues the rabbit across the sky. On the other hand, others say that the winged messenger god Hermes placed the speedy rabbit in the sky as an honor.

The stars of Lepus the Hare

The 2nd and 3rd magnitude stars of Lepus look a bit like a pinwheel with stars streaming out from its center. So, do the stars form the shape of the limbs or ears of a rabbit to you? The brightest star in this pinwheel is the star at the center, Alpha Leporis. Also known as Arneb, Alpha Leporis is magnitude 2.58 and shines from a great distance of 1,284 light-years. The next brightest star in Lepus is three degrees south of Alpha. Beta Leporis, or Nihal, is magnitude 2.81 and lies almost 10 times closer than Alpha, at 160 light-years. No other stars in Lepus have formal names.

Lepus’s globular cluster

Lepus contains one Messier object, M79. M79 is a globular cluster, a huge group of ancient stars that orbits the Milky Way. You can find it by using the stars Alpha and Beta. Draw a line from Alpha to Beta, which will be about three degrees in length, and then continue the line straight south for four degrees until you come upon the 8th magnitude globular cluster. You can spot it in binoculars from a dark sky, but it looks even better in a telescope.

M79 lies about 40,000 light-years away from Earth but 60,000 light-years away from the galactic center. Notably, its location is unusual for a globular cluster. Most globular clusters are closer to the galaxy’s core than we are, orbiting the general bulk at its center. M79, however, is farther away, on the outskirts of the galaxy. Indeed, this discovery leads scientists to believe it is actually an extragalactic cluster.

In fact, some scientists believe the globular cluster M79 once belonged to a neighboring dwarf galaxy that the Milky Way ate. Others believe the dim, dispersed dwarf galaxy still exists just beyond the Milky Way but that it will soon intermingle and become part of the Milky Way’s stars.

Bottom line: Lepus the Hare is a constellation that lies below Orion. You can best spot it on January evenings. It’s home to globular cluster M79.

Read more about a discovery in Lepus: Have astronomers found a hyper-volcanic exomoon?

The post Lepus the Hare hops through the January sky first appeared on EarthSky.

Eridanus the River

You’ll need a dark sky to see Eridanus the River. You won’t see this constellation from the city, or even the suburbs. The River begins near the star Rigel in the constellation Orion the Hunter and wells up in a great loop before ambling back down toward the southern horizon.

Eridanus is one of the longest and faintest constellations. But it’s very noticeable in a dark sky. It was one of the 48 constellations listed by the second century astronomer Ptolemy. The International Astronomical Union (IAU) included it on its list of 88 official modern constellations. Eridanus is the sixth largest of the modern constellations. It’s the one that extends farthest in the sky from north to south.

Why to search for such a faint constellation? Only because it’s beautiful. And seeing Eridanus – understanding its association with a river in the minds of the early stargazers – can give you a kinship with those stargazers from centuries ago.

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How to find Eridanus

From the Northern Hemisphere, look southward for Eridanus on northern winter evenings, say, in the month of January. At this time of year, the noticeable constellation Orion the Hunter is making its great arc across the southern sky. Orion is the key to seeing Eridanus. The River begins at Orion’s bright star Rigel. It then swells up in its mighty loop, before meandering back southward. From most of the U.S., the River disappears before its end below the southern horizon. But if you live at a very southerly latitude in the Northern Hemisphere, you can see a special sight: the bright star that represents the end of the River. This star is Achernar.

From the Southern Hemisphere, Orion is still helpful as a guide to seeing Eridanus. About two hours after sunset in January, part of the River will pass straight overhead. Those in the Southern Hemisphere can easily trace the entire River from near Rigel in Orion through the zenith to its bright star Achernar. Achernar lies at the end of the River not far from the Small Magellanic Cloud in Tucana the Toucan.

The River in skylore

Over the years, this long, winding constellation has represented the Nile in Egypt, Euphrates in western Asia, or the River Po in Italy. Eridanus also holds the nickname of the River of Orion, or River of Ocean. In Homer‘s day in ancient Greece, people thought that the River of Ocean encircled a flat Earth.

The mythology of Eridanus ties it to Phaethon. Phaethon was the son of Helios, the god of the sun. When he tried to fly his father’s chariot, he was unable to control the horses. The chariot veered wildly in different directions, scorching both Earth and heaven. Zeus struck the wayward Phaethon dead with a lightning bolt, and Phaethon fell into the River Erdianus. The constellation was sometimes the path Phaethon drove; other times, it was the path of souls.

Bottom line: Can you find the long, meandering river of stars called Eridanus in your sky? Be sure to look from a dark location.

The post See Eridanus the River in the January sky first appeared on EarthSky.

For those of us in the Northern Hemisphere, winter is the best time to observe the constellation Canis Major the Greater Dog. It’s easy to find since it follows Orion the Hunter up from the horizon, heading from southeast to southwest. Also, Sirius is the brightest star not only in Canis Major but in the entire sky. The fact is, it’s so bright in our sky because it’s one of the closest stars to Earth, at 8.6 light-years away.

The mythology of Canis Major

Canis Major is the Greater Dog, one of Orion’s two hunting dogs that follow him in the sky. Likewise, Canis Minor the Lesser Dog also has a bright star – the eighth brightest in the sky – Procyon. The mythological story says that the two dogs are pursuing a rabbit, and, indeed, the constellation Lepus the Hare is close to Canis Major and just below the feet of Orion.

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Finding Sirius and Canis Major

Conveniently, Canis Major is easy to find. Its bright star Sirius and location near Orion make it one of the easiest constellations to spot in the night sky. On winter evenings in the Northern Hemisphere, Orion rises first from the southeastern horizon, and bright Sirius anchoring Canis Major follows. In addition, Sirius marks the location of the Greater Dog’s collar. The head is a dimmer triangle, but bright stars mark his front foot and his rear flank and tail.

The stars of Canis Major

Sirius holds the nickname of the Dog Star because it lies in the constellation of the Greater Dog. At magnitude -1.44, it outshines every other star in the sky as seen from Earth. Sirius, which also has the more formal name of Alpha Canis Majoris, is a binary star system. Sirius A is the younger, hotter and brighter star, with Sirius B playing the part of the dim companion.

Correspondingly, the second brightest star in Canis Major is toward the back portion of the dog, where its hind leg would connect with its body. This star is Adhara, also known as Epsilon Canis Majoris, a magnitude 1.5 beacon lying 430 light-years away. And then, just above on the Greater Dog’s body, where the tail connects to the torso, is Wezen, also known as Delta Canis Majoris, a magnitude 1.83 star that would be much brighter than Sirius if it were closer. Wezen lies about 1,800 light-years away.

The fourth brightest star in Canis Major is 5 1/2 degrees from Sirius, marking the front foot of the dog. This star is Mirzam (Beta Canis Majoris), a magnitude 1.98 star. It’s about 500 light-years distant. Finally, the last bright star in Canis Major is back toward the rear of the dog. Aludra (Eta Canis Majoris), at magnitude 2.45, marks the tip of the Dog’s tail. As a matter of fact, it lies farther away than all the other bright stars in Canis Major, at 3,000 light-years.

In addition, three stars form a triangle near Sirius and mark the Dog’s head. They’re best seen from dark skies. They range in magnitude from 4.0 to 4.3.

Deep-sky objects in the Greater Dog

There is only one Messier object in Canis Major, and that is M41. M41 is a relatively bright open cluster that shines with a magnitude of 4.5. The cluster lies about four degrees from Sirius, in the general location of what would be the Dog’s heart. Of course, you should be able to spot it without any optical aid, but binoculars improve the view.

Also, there’s a pretty nebula in Canis Major that’s beautiful in astrophotos, even if it’s too far away and dim for you to see through binoculars. In the corner of the constellation above the dog’s head, almost nine degrees northeast of Sirius, is NGC 2359, or Thor’s Helmet. This strange-looking nebula has a massive Wolf-Rayet star at its core. The nebula has a central bubble shape, with appendage-like tentacles streaming out on various sides. Lying about 15,000 light-years away, this nebula has a magnitude of 11.45, a good challenge for telescope owners.

Bottom line: Canis Major the Greater Dog is most famous for being home to the brightest star in the sky, Sirius. Of course, you can’t miss Sirius in the evening sky.

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Aries the Ram isn’t a noticeable constellation. It ranks as the 11th smallest out of the 12 zodiacal constellations. And its stars are only moderately bright. But the giant planet Jupiter lies in front of Aries now. And December and January are great months to spot this faint constellation, with Jupiter’s help. Although Aries has few bright stars, there’s much to see telescopically within this constellation. And it figures prominently into the history of astronomy.

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How to see Aries the Ram

The best time to behold the Mighty Ram is when the Earth is on the other side of the sun from this constellation. The months around the December solstice are especially good for viewing Aries the Ram in all his starlit majesty. During those months, this constellation shines above the eastern horizon at nightfall and stays out for most of the night. Aries culminates – reaches its highest point in the sky – at about 10 p.m. your local time in late November, 8 p.m. your local time in late December and 6 p.m. your local time in late January.

Because Aries isn’t a particularly prominent constellation, you’ll want a dark country sky, on a night when there’s no moon. The three stars depicting the Ram’s bust – Hamal, Sheratan and Mesartim – suddenly brighten in a dark sky. In fact, it’s as if someone had turned up the dimmer switch. By the way, a small telescope reveals that Mesartim is a double star.

Fortunately, the head of the Ram is fairly easy to locate. You’ll find it midway between these two signposts: the Pleiades star cluster to the east and the Great Square of Pegasus to the west. The Ram’s head is turned backward, as if admiring the Pleiades, or perhaps his own golden fleece.

What is the First Point of Aries?

The First Point of Aries marks the sun’s position in front of the constellations of the zodiac on the Northern Hemisphere’s spring equinox or Southern Hemisphere’s autumnal equinox. This equinox happens yearly on or near March 20, as the sun crosses the celestial equator, going from south to north.

Also, the First Point of Aries, which is actually in the constellation Pisces nowadays, defines the coordinate system on the celestial sphere. The First Point of Aries always coincides with zero degrees right ascension and zero degrees declination. Right ascension is the equivalent of longitude here on Earth. Declination on the sky’s dome is the equivalent of latitude.

In addition, the First Point of Aries is one of two places on the celestial sphere where the ecliptic and celestial equator intersect. Then the First Point of Libra resides 180 degrees east of the First Point of Aries, marking the September equinox point on the celestial sphere.

What is the First Point in Pisces?

Since the Earth’s rotational axis wobbles full circle relative to the backdrop stars in about 26,000 years, Polaris doesn’t remain the North Star forever. In turn, that means the equinox points don’t remain fixed relative to the stars of the zodiac. So, the March equinox point drifts westward (along the ecliptic) through the constellations of the zodiac at about one degree (two sun diameters) in 72 years, or 30 degrees in 2,160 years.

Hence, the March equinox point passed out of the constellation Aries and into the constellation Pisces in 68 B.C. Even so, we still call this equinox point the First Point of Aries.

Hamal, brightest star in Aries

Hamal, or Alpha Arietis, is the brightest star in Aries. This orange giant star shines at magnitude 2 and lies a bit more than 65 light-years from Earth.

In fact, Hamal means head of the ram, a fitting name. Also, sailors once used Hamal to help in navigation. And the star is the 50th brightest in the sky.

The celestial Ram in star lore

In Greek mythology, Aries represents the supernatural Ram that was sent by Zeus to rescue the children of Athamus, the King of Thebes, from political intrigue. Phrixus and his sister Helle were about to meet their demise, but the flying Ram, which could both speak and reason, took them away in the nick of time.

The children held on tight as the Ram flew them away for the safety of Colchis, an ancient kingdom bordering the eastern shore of the Black Sea. Unfortunately, Helle fell into the sea and drowned before reaching their destination. Hellespont – the ancient name for the Dardanelles Strait near Istanbul, Turkey – marks the place of her death, named in her honor.

Phrixus survived the long trip to Colchis. He gave thanks by sacrificing the Ram to Zeus, hanging it in a sacred grove where the fleece turned to gold. Later, Jason and the Argonauts recovered the Golden Fleece.

Bottom line: How to see the constellation Aries the Ram, plus info about this constellation in the history of astronomy and mythology.

All 12 (13) zodiac constellations

Taurus? Here’s your constellation
Gemini? Here’s your constellation
Cancer? Here’s your constellation
Leo? Here’s your constellation
Virgo? Here’s your constellation
Libra? Here’s your constellation
Scorpius? Here’s your contellation
Sagittarius? Here’s your constellation
Capricornus? Here’s your constellation
Aquarius? Here’s your constellation
Pisces? Here’s your constellation
Aries? Here’s your constellation

The post Aries the Ram – and Jupiter – in the evening sky first appeared on EarthSky.

Orion the Hunter is arguably the most recognizable constellation in the world. Orion lies on the celestial equator, making it visible from both the Northern and Southern Hemispheres. Orion’s shape is easy to pick out because of its many bright stars and signature Orion’s Belt: three stars close together in a nearly straight line.

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Mythology of Orion the Hunter

In many drawings of the constellation Orion, the Hunter looks to be battling his neighbor, Taurus the Bull. Yet there is no such story in the mythology of Orion. Some stories have Orion pursuing the seven sisters of the Pleiades, which is a star cluster in the constellation Taurus. On the other side of Orion are his hunting dogs, Canis Major and Canis Minor (not to be confused with Canes Venatici, a different constellation with the actual nickname of the Hunting Dogs).

Mythology says that a scorpion killed Orion; that’s why Orion is on one side of the sky while Scorpius the Scorpion is on the opposite side. As Scorpius is about to rise in the east, Orion makes a hurried exit from the sky in the west.

Brightest stars in Orion

The brightest star in Orion is the bluish Rigel, which marks his western knee or foot. Rigel is a blue supergiant 770 light-years away with a magnitude of +0.2. Rigel is the seventh brightest star in the entire sky. The star marking the other knee or foot of Orion is Saiph, a magnitude 2.1 star. It’s a blue supergiant and 720 light-years distant.

The second brightest star in Orion is reddish-orange Betelgeuse, which marks one shoulder. Betelgeuse is the 10th brightest star in the sky at magnitude 0.5. It’s a red supergiant 550 light-years away and a whopping 800 times larger than our sun. If we substituted Betelgeuse for our sun, it would swallow up all the inner planets.

The third brightest star of Orion, which marks his other shoulder, is Bellatrix. Bellatrix, a blue supergiant shining at magnitude 1.6, is the 22nd brightest star in the sky and 245 light-years away.

Other stars in Orion

Extending out from Bellatrix is Orion’s arm, where he is holding either a shield or an animal, depending on the artist’s concept. The brighter stars marking this object are all of 3rd and 4th magnitude.

Extending upward from Betelgeuse is Orion’s other arm, which holds a club or sword. The brightest stars in the arm and club are all 4th magnitude.

The stars that make up Orion’s head are a test of your sky’s darkness. They range from 3rd magnitude to 6th magnitude. The more stars you can see, the better your skies are.

The three Belt stars from east to west are Alnitak (magnitude 1.8), Alnilam (magnitude 1.7) and Mintaka (magnitude 2.2).

Nebulae of Orion the Hunter

The stars in the Sword that hangs down from the Belt are part of the Orion Nebula (M42). You can see the nebula, or cloud of gas, without optical aid as a hazy, 4th-magnitude patch. Using magnification reveals a quadruple star at the center of the nebula. These four newborn stars – the Trapezium Cluster – light up their dusty cocoon, making its glow visible to us here on Earth, a vast 1,400 light-years away.

The famous Horsehead Nebula lies near the Belt star Alnitak. This dark nebula is a faint target even for most amateur telescopes; your best bet is to view it in a picture compliments of an astrophotographer. (Learn more about dark nebulae.)

Along Orion’s side between Alnitak and Betelgeuse (but closer to the belt stars) is the 8th-magnitude nebula M78. M78 has the awkward title of “brightest diffuse reflection nebula in the sky.” One more notable nebula in Orion is near Rigel and crosses into Eridanus the River. IC 2118, the Witch Head Nebula, is extremely faint but also extremely large, spanning six full moons.

EarthSky Community Photos of Orion

Bottom line: Orion the Hunter may be the most recognizable constellation in the world. It’s visible from the north in winter and from the south in summer.

Read more: Orion the Hunter is easy to spot

The post Orion the Hunter, the most recognizable constellation first appeared on EarthSky.

On the nights until December 22, 2023, watch for the moon, as it will pass above the constellation Cetus the Whale. The moon will near the tail of Cetus, cross above the body and then appear near the whale’s head. So the moon can be your guide to Cetus on these nights. What else is nearby? Only our solar system’s largest planet, and the brightest “star” in the evening sky, Jupiter.

Cetus the Whale doesn’t have Jupiter’s brightness. But it’s noteworthy as the 4th-largest of the 88 constellations. Only Ursa Major the Great Bear, Virgo the Maiden and Hydra the Water Snake are bigger. Also, Cetus lies in a part of the night sky that represents a celestial sea. You’ll find it below Pisces the Fish and Eridanus the River. Other water-themed constellation inhabit this region of the sky as well.

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The mythology of Cetus

In Greek mythology, Cetus was a fearsome sea monster. Cetus nearly ate Andromeda the Chained Lady before Perseus the Hero arrived and saved the day, slaying Cetus. And depending on the myth you read, Cetus either meets its fate on the sword of Perseus or by turning to stone after viewing the severed head of Medusa.

The stars of Cetus the Whale

The brightest star in the head of Cetus is Menkar, shining at magnitude 2.54, but it’s the second brightest star in the body Cetus and also goes by the name Alpha Ceti. It’s located about 250 light-years away.

The star that marks where the whale’s head joins its neck is the 3.47-magnitude star Kaffaljidhma, or Gamma Ceti. Moving toward the body of the whale is Delta Ceti at magnitude 4.08. Delta will be useful later for finding Cetus’ one prominent galaxy.

The next star in the body of the whale is the famous Mira the Wonderful. Mira, or Omicron Ceti, is a popular variable star, which is one that changes in brightness. This long-period variable star can get as bright as magnitude 2 and as dim as magnitude 10. When you compare it to the other stars in Cetus, how bright does Mira look tonight? Another curious feature of Mira is that it is rushing through space at 290,000 miles per hour (466,000 km/h). This immense speed and the fact that Mira is nearing the end of its life and ejecting material means the wonderful star sports a tail that stretches for an incredible 13 light-years.

The brightest star in Cetus goes by three different names: Beta Ceti, Diphda and Deneb Kaitos. This star shines at magnitude 2, lies in the tail of the beast and is 96 light-years away.

Finally, the star Earendel is the most distant star ever detected. As a matter of fact – it is so distant – it emitted the light we now see some 12.9 billion years ago.

Galaxies in Cetus the Whale

The only Messier object in Cetus is the Squid galaxy or M77. It lies just a degree east-southeast of the star Delta Ceti. M77 shines at magnitude 8.8 from 47 million light-years away. The face-on spiral galaxy has an active galactic nucleus and a noticeably bright center. Those with large telescopes may be able to catch another galaxy between Delta Ceti and M77. The magnitude -10.6 galaxy NGC 1055 resides there.

By the way, M77 is generally the first object to find if you’re doing a Messier Marathon in spring. That’s because it slips away fast in the western evening twilight that time of year.

Nebulae in Cetus the Whale

One notable planetary nebula lies six degrees north of the brightest star Diphda, or Deneb Kaitos. NGC 246 has a magnitude of 8. The nebula has a bubble or ring-shaped appearance and is 1,600 million light-years away.

Planetary nebulae come into being when stars puff off material toward the end of their lives. Mira will eventually create another planetary nebula in Cetus when it ends its life and ejects its remaining gas. As a fitting moniker for a star that has given up the ghost, NGC 246 also bears the nickname of the Skull nebula.

Bottom line: Cetus the Whale is a huge constellation that swims in a sea of stars near constellations named for a river and fish. Its most notable star is Mira the Wonderful. The moon – and Jupiter – are near Cetus from December 19-23, 2023.

The post Look for Cetus the Whale swimming in a celestial sea first appeared on EarthSky.