Watch the full Countdown to Eclipse series.

Act fast if you want reservations for places to stay near the path of totality of the total solar eclipse of April 8, 2024. After this event, we won’t have another total solar eclipse visible from the contiguous U.S. until 2044! The eclipse path will sweep across North America, Mexico and eastern Canada. A partial solar eclipse will be visible over North and Central America.

Total solar eclipse

Partial eclipse begins: at 15:42 UTC (11:42 a.m. EDT) on April 8.
Total eclipse begins: at 16:38 UTC (12:38 p.m. EDT) on April 8.
Greatest eclipse: at 18:17 UTC (2:17 p.m. EDT) on April 8.
Total eclipse ends: at 19:55 UTC (3:55 p.m. EDT) on April 8.
Partial eclipse ends: at 20:52 UTC (4:52 p.m. EDT) on April 8.
Note: The instant of greatest eclipse – when the axis of the moon’s shadow cone passes closest to Earth’s center – takes place at 18:17 UTC (2:17 p.m. EDT). It’s a relatively long total eclipse with a duration of totality lasting 4.47 minutes.

Remember that the number one rule for solar eclipse observing is to make sure you protect your eyes by using an appropriate filter.

Need eclipse glasses? Get ’em here, but order soon!

Don’t miss the great eclipse maps below.

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Moon, constellation, Saros

Greatest eclipse takes place one day after the moon reaches perigee, its closest point to Earth for the month. During the April 8, 2024, eclipse, the sun is located in the direction of the constellation Aries.

This eclipse has a magnitude of 1.0566.

The Saros catalog describes the periodicity of eclipses. The eclipse belongs to Saros 139. It is number 30 of 71 eclipses in the series. All eclipses in this series occur at the moon’s ascending node. The moon moves southward with respect to the node with each succeeding eclipse in the series.

Cities where the total solar eclipse is visible

Next eclipse and eclipse seasons

The total solar eclipse of April 8, 2024, is preceded two weeks earlier by a penumbral lunar eclipse on March 24, 2024.

These eclipses all take place during a single eclipse season.

An eclipse season is an approximate 35-day period during which it’s inevitable for at least two (and possibly three) eclipses to take place. The next eclipse season has three eclipses: September 17-18, October 2 and October 17, 2024.

Maps and data

Find maps and eclipse timings below. Remember to convert UTC to your time.

• Timeanddate.com: to get the exact timing of the eclipse from your location.
• Orthographic Map: detailed global map of eclipse visibility.
• Google Map: interactive map of the eclipse path.
• Path Table: coordinates of the central line and path limits.
• Circumstances Table: eclipse times for hundreds of cities.
• Saros 139 Table: data for all eclipses in the Saros series.
• Additional tables and data.

Here is what a total solar eclipse looks like

Eclipse maps from Great American Eclipse

Michael Zeiler of GreatAmericanEclipse.com has generously given us permission to share his eclipse maps for the total solar eclipse. Here you can get a better idea of where you’ll want to be and when to see this unique phenomenon.

Which location is closest to you?

Maps for the timing of the eclipse

How long will the eclipse last?

Read more: Total solar eclipse of April 8, 2024, from Michael Zeller

Watch the full Countdown to Eclipse series.

Bottom line: We’re counting down to the April 8, 2024, total solar eclipse, which will cross North America. Join us for a countdown! February 21, 2024, is 47 days until eclipse day. In this episode, Marcy Curran shares some fun facts of solar eclipses.

Read more from EarthSky: Tides, and the pull of the moon and sun

See photos of the December 2021 solar eclipse

EarthSky’s monthly planet guide: Visible planets and more

The post 47 days to total solar eclipse. Eclipse fun facts first appeared on EarthSky.

Cassiopeia the Queen in late winter and early spring

On late northern winter evenings and throughout spring, Cassiopeia the Queen descends in her throne in the northwest after nightfall. Cassiopeia is one of the easiest constellations to spot because of its distinctive shape. Cassiopeia looks like the letter W or M. Look for the Queen as your sky gets dark in February and March. She’ll be lower in the northwest as spring begins to unfold. For those in the northern U.S. and Canada, Cassiopeia is circumpolar, or above the horizon all night every night.

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The stars of Cassiopeia

Cassiopeia is home to five bright stars that form the W shape. Some describe these stars as outlining the chair – or throne – she sits upon. If you’re viewing Cassiopeia as the letter W, the stars, from left to right, are Segin, Ruchbah, Gamma Cassiopeiae, Schedar and Caph.

How to find Cassiopeia

Cassiopeia is opposite the Big Dipper in the northern sky. That is, the two constellations lie on opposite sides of the pole star, Polaris. So when Cassiopeia is high in the sky, as it is on evenings from about September through February, the Big Dipper is low in the sky. Every March, when the Dipper is ascending in the northeast, getting ready to appear prominently again in the evening sky, Cassiopeia is descending in the northwest.

Neighboring star clusters

If you have a dark sky, look across the border of Cassiopeia into Perseus the Hero for a famous binocular object. It’s the Double Cluster in Perseus. They are open star clusters, each of which consists of young stars still moving together from the primordial cloud of gas and dust that gave birth to them.

In fact, these clusters have a unique set of mismatched names: H and Chi Persei. Their names are from two different alphabets, the Greek and the Roman. Stars have Greek letter names, but most star clusters don’t. Johann Bayer (1572-1625) gave Chi Persei – the cluster on the top – its Greek letter name. Then, it’s said, he ran out of Greek letters. That’s when he used a Roman letter – the letter H – to name the other cluster.

Lore of the Queen

In sky lore and in Greek mythology, Cassiopeia was a beautiful and vain queen of Ethiopia. It’s said that she committed the sin of pride by boasting that both she and her daughter Andromeda were more beautiful than Nereids, or sea nymphs.

Her boast angered Poseidon, god of the sea, who sent a sea monster (Cetus the Whale) to ravage the kingdom. To pacify the monster, Cassiopeia’s daughter, Princess Andromeda, was left tied to a rock by the sea. Cetus was about to devour her when Perseus the Hero happened by on Pegasus the Winged Horse.

Then, Perseus rescued the princess, and all lived happily … and the gods were pleased, so all of these characters were elevated to the heavens as stars.

But – because of her vanity – Cassiopeia suffered an indignity. At some times of the night or year, this constellation has more the shape of the letter M, and you might imagine the Queen reclining on her starry throne. At other times of the year or night – as in the wee hours between midnight and dawn in February and March – Cassiopeia’s Chair dips below the celestial pole. And then this constellation appears to us on Earth more like the letter W.

That’s when the Lady of the Chair – as she is sometimes called – is upside-down and said to hang on for dear life. If Cassiopeia the Queen lets go, she will drop from the sky into the ocean below, where the Nereids must still be waiting.

Bottom line: The constellation Cassiopeia the Queen has the distinct shape of a W or M. You’ll find her descending in her throne on late northern winter evenings and throughout spring nights.

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When and where to look in 2024: Look for the bright, round, full moon to rise in the east near sunset on January 25, 2024. It’ll be glowing nearly overhead around midnight, and dropping low in the west near sunrise.
Crest of the full moon falls at 17:54 UTC on January 25. That’s 11:54 a.m. CST.

January’s full moon is the Wolf Moon

All full moons have popular nicknames. January’s full moon is often called the Wolf Moon because – in parts of the world where they live – wolves are active in January and often howl on cold nights. Other names derived from North American indigenous people also refer to January’s cold. They include the Cold Moon, Frost Exploding Moon, Freeze Up Moon, and Hard Moon.

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January full moon path

At full moon, the sun, Earth, and the moon align in space, with Earth in the middle. As a result, the moon’s day side – its fully lighted hemisphere – directly faces us. That is why the moon appears full. Also – as seen from the Northern Hemisphere – the sun travels daily in a short, low arc across the January sky. On the other hand, the full moon, opposite the sun in the sky, travels in a long, high arc across the sky, and passes nearly overhead around local midnight. Meanwhile, as seen from the Southern Hemisphere, the January sun is high, and the moon is low.

January’s full moon in front of Cancer

The January full moon can lie in front of one of two constellations of the zodiac. If the full moon falls in the first half of the month, as it did last year, it lands in Gemini the Twins. If it happens during the second half, as it does this year, it falls in Cancer the Crab.

The moon is roundest on the day when it is full, but it appears almost, but not quite full the day before and after. On the evening of this January’s full moon, the twin stars of Gemini, Castor (the dimmer one) and Pollux (the brighter one) shine nearby. However, the bright moonlight may make these two famous stars dim or even invisible. If you can’t spot them, rest assured, they are still there!

The full moon glows next to the Beehive

The pretty, but dim Beehive star cluster twinkles immediately below the full moon. It is much dimmer than Castor and Pollux, and it will be much closer to the bright moon making it indiscernible. So, to see the Beehive properly, you’ll need to come back when a bright moon isn’t in the sky.

January full moon and the July sun

Every full moon stays – more or less – opposite the sun. The moon’s path roughly follows the sun’s daytime path from six months ago, and six months from now.

In the Northern Hemisphere, you can see this happening as you watch the January full moon rise to almost the top of the sky, just as the sun does in July.

For the Southern Hemisphere, it’s the same effect, but reversed. Since it’s early summer there, the full moon in January rides low in the sky as the January sun rides high.

Tracing the high path of the January full moon

You can experiment with the path of the sun and moon. Simply trace a line with your finger from east to west along a low arc above the southern horizon to emulate the sun’s January path. Then trace another path high overhead to emulate the moon’s path in January. You’ll see that the higher path will be much longer than the lower one.

The monthly paths come into balance

Little by little, we can watch the two paths come back into balance. Each month, the full moon will cross the sky at a slightly lower arc than the previous month. Each successive full moon takes less time than the previous one to cross the sky. Since last month’s full moon was closest to the winter solstice, it rose the highest. At March’s full moon, which is near the Northern Hemisphere’s spring equinox, the two paths – of the moon and of the sun – will nearly be the same.

Then, near the June solstice, those of us in the Northern Hemisphere see the sun cross high overhead during the year’s longest days. And, during the short northern summer nights, we see the moon cross lower and spend less time in the sky.

And on the cycle goes.

Bottom line: The 2024 January full moon falls on January 25 at 17:54 UTC (11:54 a.m. CST). It’s in Cancer and appears nearby the Beehive star cluster. It also closely follows the path of the sun in July.

The post January full moon is the Wolf Moon. See it tonight! first appeared on EarthSky.

Cassiopeia and the Big Dipper in the night sky

Tonight, look for the northern sky’s two most prominent sky patterns – the constellation Cassiopeia the Queen and the Big Dipper. Cassiopeia and the Big Dipper circle around Polaris, the North Star, once a day, every day. What’s more, they are opposite each other, one on either side of the North Star.

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Cassiopeia

At nightfall, the constellation Cassiopeia the Queen is easy to recognize in the northern sky. This constellation looks like a W or M and contains five moderately bright stars. The distinctive shape of Cassiopeia makes it very noticeable among the stars of the northern sky.

The Big Dipper

And, of course, Ursa Major the Greater Bear – which contains the Big Dipper asterism – is one of the most famous star patterns. At nightfall this month, Cassiopeia shines high in the north while the Dipper lurks low. They are always on opposite sides of the North Star. From the southern half of the U.S., the Big Dipper is partly or totally beneath the horizon this month in the evening hours. North of about 40 degrees north latitude (the latitude of Denver, Colorado, and Beijing, China), the Big Dipper always stays above the horizon (if your horizon is level). To see a precise view from your location, try Stellarium Online.

They circle around Polaris all night

But remember, their positions change as the night passes, as the great carousel of stars wheels westward (counterclockwise) around Polaris, the North Star. Polaris resides halfway between Cassiopeia and the Big Dipper. As a result, they are like riders on opposite sides of a Ferris wheel. Thus, looking northward, they rotate counterclockwise around Polaris – the star that marks the sky’s north celestial pole – once a day. Approximately every 12 hours, as Earth spins beneath the heavens, Cassiopeia and the Big Dipper trade places in the sky.

Thus, around midnight tonight, Cassiopeia circles directly west (left) of Polaris, whereas the Big Dipper sweeps to Polaris’ east (right). And then, before dawn tomorrow the Big Dipper climbs right above the North Star, while Cassiopeia swings directly below.

Bottom line: Watch the celestial clock and its two great big hour hands – Cassiopeia and the Big Dipper – as they swing around the North Star every night!

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Tonight look for the constellation Orion the Hunter. It’s a constant companion on winter evenings in the Northern Hemisphere, and on summer nights in the Southern Hemisphere. Plus, it’s probably the easiest constellation to spot thanks to its distinctive Belt. Orion’s Belt consists of three medium-bright stars in a short, straight row at the Hunter’s waistline. So if you see any three equally bright stars in a row this evening, you’re probably looking at Orion. Do you want to be sure? There are two even brighter stars – one reddish and the other blue – on either side of the Belt stars.

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When to look for Orion

As seen from mid-northern latitudes, you’ll find Orion in the southeast in the early evening and shining high in the south by mid-to-late evening (around 9 to 10 p.m. local time, the time on your clock wherever you live). If you live at temperate latitudes south of the equator, you’ll see Orion high in your northern sky around that same hour.

What to look for in Orion the Hunter

First, look for the two brightest stars in Orion: Betelgeuse and Rigel. Rigel’s distance is approximately 860 light-years. However, the distance to Betelgeuse has been harder for scientists to determine. Its current estimate is about 724 light-years away, but uncertainties remain.

Betelgeuse dimmed for a while in late 2019, generating a fair amount of excitement, because Betelgeuse is a star on the brink of a supernova. However, the star has since returned to its normal brightness. So how bright does it look tonight?

Also, take a moment to trace the Belt of Orion and the Sword that hangs from his belt. If one of the stars in the Sword looks blurry to you, that’s because you’re actually seeing the Orion Nebula. And if you use binoculars or a telescope to look at the Orion Nebula, you’ll start to see some shape in the gas and dust cloud.

Connections between the stars

While the stars of constellations often look like they should be physically related and gravitationally bound, they usually are not.

However, some of Orion’s most famous stars do have a connection. Several of the brightest stars in Orion are members of our local spiral arm, sometimes called the Orion Arm or sometimes the Orion Spur of the Milky Way. Our local spiral arm lies between the Sagittarius and Perseus Arms of the Milky Way.

Now consider those three prominent Belt stars. They appear fainter than Rigel or Betelgeuse, and, not surprisingly, they’re farther away. As a matter of fact, they’re all giant stars located in the Orion Arm. These stars’ names and approximate distances are Mintaka (1,200 light-years), Alnilam (2,000 light-years), and Alnitak (1,260 light-years). When you look at these three stars, know that you’re looking across vast space, and into our local arm of the Milky Way galaxy.

Bottom line: Orion the Hunter is one of the easiest constellations to identify thanks to its Belt, the three medium-bright stars in a short, straight row at his waist.

Why do stars seem brighter in winter?

The post Orion the Hunter is easy to spot in January first appeared on EarthSky.

Observable comets in 2024

UK astronomer Guy Ottewell published his article about comets in 2024 at his website on January 12, 2024. Reprinted with permission. Edits by EarthSky.

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Comets are always unpredictable

The predicted brightness of a comet – an icy visitor, often from the outermost reaches of our solar system – can and does change frequently. For example, a comet’s orbital elements can change, as observations are continually sent in by observers around the world. Or, a comet’s brightness parameters may be changed. The brightness predictions are based on a comet body’s size (typically around six miles, or 10 km, in diameter) and the rate at which it brightens by shedding cloudy material as it approaches the sun.

Also, new comets can and do appear from the depths of space.

So comets don’t always behave as we think they will! That said, my calculations suggest the comets in the chart below will be brighter than 9th magnitude in 2024. That is, they’ll be bright enough to observe with binoculars or small telescopes in dark sky.

More about this chart

Just so you know … the above list of observable comets – and their brightnesses or magnitudes – can change at any time.

See the note at the bottom of this post to learn how I calculated 2024’s observable comets. After disentangling my calculations, I find these comets might be brighter than magnitude 9.5 in 2024. In other words, these are the comets you might see with ordinary 7X50 binoculars. And, if we’re lucky, some of these comets could become visible to the eye alone.

By the way, the 9.5 magnitude threshold is arbitrary. Changing it admits more or fewer comets. Also, there is always the caution that their actual behavior can depart wildly from what’s predicted. That’s because comets can flare, or shed so much of their cloudy material that they become like asteroids. Or comets can break into several bodies, and completely disintegrate and disappear. Never bet on a comet! Additionally, there are often new comets of the non-periodic kind, which are unpredictable and are liable to be among the brightest. These can arrive from deep space at any time.

Comet 62P Tsuchinsha

62P Tsuchinsha’s designation means that it was the 62nd comet to be recognized as periodic – that is – with elliptical orbit of under 200 years. And it was at its brightest for 2024 on January 1, 2024. That’s because it passed its peak brightness on December 25, 2023. However, reports are that it may be running about one magnitude brighter than predicted and is currently shining around magnitude nine.

It will be nearest to Earth (0.495 AU) on January 29, 2024, but half a magnitude dimmer because it’s farther from the sun. And then, it will keep climbing higher in the morning sky until we pass it at opposition on March 24. Unfortunately, it will probably have faded to magnitude 12 by then.

Comet C/2021 S3 PANSTARRSS

C/2021 S3 PANSTARRSS was one of the discoveries of the automated search program Pan-STARRS (Panoramic Survey Telescope and Rapid Response System, on Mount Haleakala in Hawaii). And S3 means it was the third comet discovery or recovery in the second half of September. By the way, it approached us from the south, in a vast and steeply inclined orbit (eccentricity given as 1.0002, inclination 58.5 degrees).

So, in contrast to 62P, it is running fainter than the prediction. It will cross the ecliptic plane northward on February 7, 2024, and pass through perihelion (closest to the sun, 1.32 AU, not far outside Earth’s orbit) on February 14. Then, around February 28, it should be at its brightest, about magnitude seven. Afterward, it’ll cross the celestial equator northward on March 4 and be nearest to Earth (1.29 AU) on March 14. Later, by the end of May it’ll be around magnitude 10. Finally, in August, when it’s at opposition (2.5 AU away from us) and far north in the sky, it’ll probably be a dim magnitude 12.

Comet 12P/Pons-Brooks

Comet 12P/Pons-Brooks is a periodic comet (a comet that has an orbit around the sun less than 200 years) discovered by Jean-Louis Pons in 1812 and then recovered by William Robert Brooks in 1883. It orbits the sun every 71 years. At perihelion – or its closest approach to the sun – it will be about 0.78 astronomical units (AU) from the sun. Its aphelion – or its furthest point from the sun – is about 17.2 AU from the sun.

In 2024 Comet 12P/Pons-Brooks is predicted to become bright enough to see with the unaided eye. Coincidentally, it’ll be closest to the sun about two weeks after the total solar eclipse on April 8 2024. So there is a chance observers may be able to see the comet during totality.

Comet 13P/Olbers

13P/Olbers is a periodic comet with an orbital period of 69 years. The comet was last seen in 1956 and its next perihelion (closest point to the sun) is on June 30, 2024. It’ll be 1.18 AU from the sun and is expected to be shining at around magnitude 7.5.

One of the brightest comets in 2024?

And, last but not least, we may have a bright comet in October 2024. Indeed, we are long overdue for a beautiful comet with a wispy comet tail stretching across our evening sky. In October 2024, especially around October 14 through 24, C/2023 A3 (Tsuchinshan-ATLAS) could be bright in the early evening sky. With ten months to go, all looks good for a great showing.

The comet will make its closest approach to the sun perihelion on September 28, 2024. At that point, some estimates are suggesting it might be around magnitude 0.7. That brightness rivals some of the brightest stars in the sky (though, for comets, the brightness is diffuse, not in a single point). Stay tuned!

Note from Guy Ottewell

The reason “hairy stars” have been absent from the last few Guy Ottewell’s Astronomical Calendars is because it was difficult to find information far enough in advance about comets likely to be observable.

I used a list of orbital elements for comets provided by the Minor Planet Center and ran calculations for the whole year to find which of them should become observable. The only criterion I’ve used is brightness (astronomically expressed as magnitude).

However, other factors can affect observability: elongation (angular distance from the sun) and declination (how far north or south in the map of the sky).

Bottom line: Here are predictions from Guy Ottewell for the observable comets in 2024. C/2023 A3 Tsuchinshan-ATLAS may be a bright comet in October 2024.

The post Observable comets in 2024, from Guy Ottewell first appeared on EarthSky.

Earth at perihelion in January

Earth’s orbit around the sun isn’t a circle. Instead, it’s an ellipse, like a circle someone sat down on. So, it makes sense that Earth has closest and farthest points from the sun each year. For 2024, our closest point comes at 1 UTC on January 3 (7 p.m. CST on January 2). This closest Earth-sun distance is called perihelion, from the Greek roots peri meaning near and helios meaning sun. In early January, we’re about 3% closer to the sun – roughly 3 million miles (5 million km) – than we are during Earth’s aphelion (farthest point) in early July. That’s in contrast to our average distance of about 93 million miles (150 million km).

NASA Earth Fact Sheet with precise perihelion and aphelion distances.

So, Earth is closest to the sun every year in early January, when it’s winter for the Northern Hemisphere.

And we’re farthest away from the sun in early July, during our Northern Hemisphere summer.

Clearly, Earth’s distance from the sun isn’t the cause of the seasons.

Today is perihelion. Earth is at its closest point to the Sun. However, Earth's orbit is so round that if you used a pencil & compass to draw an 8.5" circle on a piece of 8.5×11 paper to represent Earth's orbit, Earth would never leave the pencil line.https://t.co/9JJb2x5vZn

— Tony Dunn (@tony873004) January 3, 2024

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Earth’s orbit doesn’t cause seasons

Earth’s orbit isn’t a circle. But it’s nearly circular. And it’s not our distance from the sun that creates winter and summer on Earth. Instead, the tilt of our world’s axis with respect to our orbit causes seasons.

In winter, your part of Earth is tilted away from the sun. In summer, your part of Earth is tilted toward the sun. The day of maximum tilt toward or away from the sun is the December or June solstice.

The tilt changes the angle of sunlight falling on your part of Earth. More direct sunlight = summer. Less direct sunlight = winter.

Earth’s orbit affects length of the seasons

Though not responsible for the seasons, Earth’s closest and farthest points to the sun do affect seasonal lengths. When the Earth comes closest to the sun for the year, as we do every year in early January, our world is moving fastest in orbit. Earth is rushing along now at almost 19 miles per second (30.3 kilometers/sec), moving about 0.6 miles per second (1 kilometer/sec) faster than when Earth is farthest from the sun in early July. So the Northern Hemisphere winter and – simultaneously – the Southern Hemisphere summer are the shortest seasons, as Earth rushes from the solstice in December to the equinox in March.

In the Northern Hemisphere, the summer season (June solstice to September equinox) lasts nearly five days longer than our winter season. This holds true for the corresponding seasons in the Southern Hemisphere, as well. And the Southern Hemisphere winter is nearly five days longer than the Southern Hemisphere summer.

The 30-second YouTube video below illustrates how a planetary body speeds up around perihelion and slows down at aphelion. It’s due to Kepler’s second law of planetary motion: a line connecting the sun and a planet sweeps out equal areas in equal times.

Bottom line: In 2024, Earth’s perihelion, its closest point to the sun, is on January 3, 2024, at 1 UTC. That’s 7 p.m. CST on January 2, 2024.

The post Earth at perihelion – closest to sun – on January 2-3 first appeared on EarthSky.

Best sky scenes of 2024

Mark your calendars for the best stargazing events for 2024. From planetary pairings to a solar eclipse, from meteors to a possible spectacular comet, and from star clusters to star-forming nebulae … here they are.

Remember, for a precise view from your location, visit the free online planetarium Stellarium. Enter your location and the date of the event to see a replica of the sky where you live.

Available now! 2024 EarthSky lunar calendar. Makes a great New Year’s gift!

January 8 and 9: Venus and friends

On the morning of January 8 and 9, look to the southeast for a crowded celestial scene. On the first morning, the thin crescent moon, full with earthshine, glows next to the bright red star Antares in Scorpius. Also, for skywatchers in the southwestern US, the moon passes in front of – or occults – Antares about an hour before sunrise. For everyone in the U.S., Venus brilliantly shines to their upper left. Then, 30 minutes before sunrise, little Mercury pops above the horizon, appearing to the lower left of Venus.

Later, on the following morning, an even thinner crescent moon floats below unmistakable Venus while Mercury rises a little higher than the morning before and appears next to the moon.

March 22 to 25: Mercury makes a grand appearance

Mercury always lies close to the sun. Consequently, it never appears far above either the morning or evening twilight. From March 17 through March 25, as it nears eastern elongation, the little and sometimes elusive planet shines brightly in the western twilight 40 minutes after sunset. In a clear sky, you should be able to spot it easily.

April 8: A total (and partial) solar eclipse in North America

For millions, the biggest event of the year will be the total solar eclipse that will travel along a 115-mile-wide band stretching across North America. On the afternoon of April 8, the moon moves across the disk of the sun. And, if you are in the path of totality, the moon completely covers the sun, revealing a spectacular sight. Observers outside the path will see a partial eclipse, where the moon does not completely cover the sun. To view the partial stages of this event, you must wear proper eclipse glasses. Don’t have any? Order them here before they sell out!

April 10 and 11: Moon, Jupiter and star clusters create a captivating scene

A lovely crescent moon shines near a collection of beautiful objects on the evenings of April 10 and 11. The bright point of light shining nearby is Jupiter. In addition, the dipper-shaped Pleiades star cluster – or Seven Sisters – is a favorite sight among stargazers. And the larger, V-shaped Hyades star cluster with its bright red foreground star, Aldebaran, ranks highly as well. Look west-northwest about an hour after sunset. What a great sight to end your day!

July 7: The crescent moon and Mercury

The thin crescent moon – lying low in the bright western-northwestern twilight sky on July 7 – will be a convenient guide for finding little Mercury. Simply look toward the moon about 40 minutes after sunset. The planet will be between the moon and the horizon. Binoculars give a clearer view. Place the moon at the upper edge of the field, and Mercury will be near the field’s center.

July 30 and 31: The crescent moon, Jupiter and Mars

An attractive scene plays out on the last two mornings of July. First, on July 30, the crescent moon floats among bright Jupiter, red Mars, the bright star Aldebaran, and the pretty Pleiades star cluster. They’re all in the eastern sky two hours before sunrise. Then, next morning the moon, as an even thinner crescent, hangs below the celestial grouping.

August 12: The Perseus meteor shower peaks

After 11 p.m. local time on August 11, begin looking toward the northeast for streaking meteors from the Perseid meteor shower. You can watch for meteors through dawn on the morning of August 12. Since the moon sets near midnight, its light interferes little with spotting meteors, which may number up to 50 per hour, perhaps more. They appear to emanate from the constellation Perseus, which is near the more familiar W–shaped constellation Cassiopeia. To be sure, the Perseids likely will be 2024’s best meteor shower.

August 14: Conjunction between red Mars and bright Jupiter

From mid-July through mid-August, red Mars will slowly approach bright Jupiter in Taurus the Bull. Then, on the morning of August 14, Mars will be less than the width of a full moon from Jupiter.

Late August mornings: 6 planets before sunrise

By this time, you’ve probably already seen Jupiter and Mars in the morning sky, coming off their conjunction in mid-August. You’ve probably spotted Saturn, too, farther to the west. But in late August, there are six planets in the morning sky. Can you challenge yourself to spot them all? Mercury will be rising before the sun. The later in the month you look, the better your chance to see it, creeping up from the eastern horizon. Uranus and Neptune will require optical aid and finder charts. Uranus is currently in Taurus while Neptune is in Pisces. You can use Stellarium to help track them down.

October 5, November 4 and December 4: The crescent moon meets Venus

Some of the most eye-catching sky sights happen when a crescent moon appears near the brightest planet, Venus. Indeed, three such occasions occur in fall’s evening sky. As the twilight sky deepens after sunset on October 5, November 4 and December 4, look toward the western horizon for a dramatic scene. Venus will be unmistakable shining next to the waxing crescent moon.

October 14 to 24: Comet Tsuchinshan–ATLAS at its brightest

A beautiful, graceful cometary apparition might be in store for us. It’s been a while since we’ve had a wispy comet tail stretch across our evening sky. This October, in particular October 14 through 24, Comet Tsuchinshan–ATLAS could be bright in the early evening sky. With ten months to go, all looks good for a great showing.

November 12: Venus shines near a mysterious glow

Brilliant Venus will shine low above the southwestern horizon on November 12 about an hour after sunset. And, just above it lies the mysterious star-forming nebula, M8, or the Lagoon Nebula. Center Venus in binoculars and the indistinct glow of M8 will become apparent.

December 5: Mars meets stellar bees

Mars visits the stellar bees of the Beehive star cluster in Cancer on December 5. Look northeast around 11 p.m. your local time for the red planet. Directly next to it will be the dim glow of the cluster. Use binoculars to see Mars standing over the many glittering stars of the Beehive.

Bottom line: Check out the best sky scenes of 2024! A total solar eclipse crosses North America, planets have close pairings, a comet may shine bright and more!

The post Best sky scenes of 2024: What not to miss! first appeared on EarthSky.

Latest sunrises

If you get up early, you know that, in late December and early January, your sunrises are still coming very late. In fact, they’re the latest sunrises of the year for people at mid-northern latitudes (say, the latitude of the central U.S.). Overall, our days have been growing longer since the December solstice. But the sunrises have still been coming later and later. That’s due to an unvarying sequence each year – earliest sunset in early December, shortest day at the solstice around December 21, latest sunrise in early January – for the Northern Hemisphere.

In fact, this natural order is what we can expect every year on our tilted Earth, pursuing our elliptical orbit around the sun.

Meanwhile, if you live in the Southern Hemisphere, you’re in the midst of an equally lovely, but more bittersweet, time of year for sunrises and sunsets. That’s because your earliest summer sunrises happened a few weeks ago. And your latest sunsets are beginning around now, and will extend for the next couple of weeks, assuming you’re at mid-southern latitudes. So your sequence is: earliest sunrise in early December, longest day at the December solstice, latest sunset in early January.

Visit Sunrise Sunset Calendars to make your custom sunrise-sunset calendar.

The 2024 lunar calendars are here! Best New Year’s gifts in the universe! Check ’em out here.

Clock time and sun time

The December solstice always brings the shortest day to the Northern Hemisphere and the longest day to the Southern Hemisphere. But, clearly, the latest sunrise doesn’t coincide with the day of least daylight. And the latest sunset doesn’t happen on the day of greatest daylight. Why not?

The main reason is that the Earth’s rotational axis is tilted 23.5 degrees out of vertical to the plane of our orbit around the sun. A secondary reason is that the Earth’s orbit isn’t a perfect circle. Due to our eccentric orbit (that’s an orbit shaped like a squashed circle, with the sun slightly off center), Earth travels fastest in January and slowest in July.

So clock time gets a bit out of sync with sun time by about 1/2 minute per day for several weeks around the December solstice.

And because solar noon (midday) comes later by the clock now than on the solstice, so do the times of sunrise and sunset. The table below helps to explain:

For Philadelphia, Pennsylvania

The sequence is always the same

The exact date for the latest sunrise or latest sunset varies by latitude. This week, mid-temperate latitudes in the Northern Hemisphere are waking up to their latest sunrises, while the Southern Hemisphere’s mid-temperate latitudes are watching their latest sunsets. At latitudes closer to the equator, the latest sunrise or latest sunset has yet to come. Closer to the Arctic or Antarctic Circles, the latest sunrise or latest sunset has already come and gone.

But in either the Northern or Southern Hemisphere, the sequence is always the same:

1) earliest sunset, winter solstice, latest sunrise
2) earliest sunrise, summer solstice, latest sunset

Bottom line: Do you notice the time of sunrise and sunset at this time of year? If you’re in the Northern Hemisphere, at mid-northern latitudes, your latest sunrises happen around early January. If you’re in the Southern Hemisphere, mid-latitudes, you are watching the year’s latest sunsets. Enjoy!

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Earth comes closest to the sun in early January

The post Latest sunrises late December and early January first appeared on EarthSky.

When and where to look in 2023: For us in the Northern Hemisphere, the bright, round full moon will rise in the east around sunset for several nights in a row: December 25, 26, and 27.
Crest of the full moon falls at 00:33 UTC on December 27. That’s 6:33 p.m. CST on December 26, and about ninety minutes after sunset in central North America. And that’s also the moment when this month’s moon is most directly opposite the sun as seen from Earth. The moon is roundest on the day when it is full, but the day before and after, it appears almost, but not quite full.

The 2024 lunar calendars are here! Best New Year’s gifts in the universe! Check ’em out here.

December full moon mimics the June sun

Every full moon is more or less opposite the sun. And a full moon’s path through the night is opposite the sun’s path. So, this December full moon’s path roughly follows the sun’s daytime path from six months ago, or six months hence. No matter where you are on Earth, notice the moon’s path on December 26-27. The Northern Hemisphere will see the December full moon rise to nearly the top of the sky, just as the sun does near the June solstice. The Southern Hemisphere will see a low moon, mimicking a low winter sun.

Here’s another way to look at it. In the Northern Hemisphere, the December solstice has the least amount of daylight of the year. Since there’s still about 24 hours in a day no matter how much daylight there is, the shortest day means it must also be the longest night. So, for the moon to stay up all night and remain roughly opposite the sun, it needs to take a longer path across the sky. The higher an object crosses the sky, the longer its path and the longer it stays above the horizon.

Tracing the high path of the December full moon

To see for yourself, try this: Trace a line with your finger from east to west to emulate the sun’s path in December. If you’re in the Northern Hemisphere, you’ll be tracing a low arc above the southern horizon. If you’re in the Southern Hemisphere, you’ll be tracing a high arc above the northern horizon.

Then, with your finger, trace another path high overhead. Now you’re emulating the moon’s December path, and you’ll see it’s a longer path than the lower one. And likewise, if you are in the Southern Hemisphere, trace a low arc to emulate the moon’s December path.

Little by little, we can watch the two paths come back into balance. Each month, the full moon will cross the sky at a slightly lower arc than the previous month. Each successive full moon will take less time than the previous one to cross the sky.

What about an equinox moon?

At March’s full moon, which is near the Northern Hemisphere’s spring equinox, the two paths – of the moon and of the sun – will be nearly the same. Then, near the June solstice, those of us in the Northern Hemisphere will see the sun cross high overhead during the year’s longest days. And, during the short northern summer nights, we’ll see the moon cross a lower path on the sky dome and spend less time in the sky.

And on the cycle goes.

Names for the December full moon

Of course, now we see why they call December’s full moon the Long Night Moon.

But – like all full moons – the full moon of December has many nicknames: Long Night Moon, Full Cold Moon, and in Decembers when it falls before Christmas, Moon Before Yule. But no matter which name appeals to you, be sure to notice the moon’s high path!

Last full moon of 2023

This full moon is the last full moon of 2023. It is also the first full moon of the Northern Hemisphere’s winter – and Southern Hemisphere’s summer.

Plus it is the closest full moon this year to the December solstice, occurring just five days after. This solstice marks the start of winter in the Northern Hemisphere and summer in the Southern Hemisphere. It lands at 3:27 UTC on December 22, 2023. That’s 9:27 p.m. CDT on December 21, 2023.

December full moon in Gemini

The December full moon can lie in front of one of two constellations of the zodiac and two additional constellations. This year it lands at the foot of Gemini, but in most years it falls in Taurus. And in 2026, it will occur in the constellation , Orion. Very rarely, though, the exact moment of full moon happens when it passes along the southern edge of Auriga.

Enjoy December’s full moon!

Bottom line: The 2023 December full moon happens overnight on December 26-27, 2023. It closely follows the path of the June sun. It also lies in the zodiacal constellation Gemini and is near that constellation’s twin stars, Castor and Pollux.

The post December full moon – Long Night Moon – mimics the June sun first appeared on EarthSky.