Visible Planets and Night Sky Guide for April

Originally published by EarthSky.

April 15: 1st quarter moon

The instant of 1st quarter moon will fall at 19:13 UTC on April 15, 2024 (2:13 p.m. CDT). A 1st quarter moon rises around noon your local time and sets around midnight. Watch for it high in the sky at sundown.

A half-lit moon on a black sky. There are many small craters and big dark areas on the lit right side.

View at EarthSky Community Photos. | Lorraine Boyd in Glen Falls, New York, captured the 1st quarter moon on November 20, 2023. Lorraine wrote: “There’s just something about seeing the moon in the 1st quarter phase that puts a smile on my face.” Thank you, Lorraine!

April 15 evening: Moon near the twin stars of Gemini

On the evening of April 15, 2024, the first quarter moon will shine near Castor and Pollux, the twin stars of Gemini. Although they are “twin brothers,” they don’t really look alike. Pollux is a bit brighter and a golden star, while Castor shines as a white light. They’ll rise before sunset and travel across the sky’s dome before setting a few hours after midnight.

Two large dots for the moon on April 14 and 15 with a small dots for Castor and Pollux.

April 17 and 18 evenings: Moon near Regulus

On the evenings of April 17 and 18, 2024, the waxing gibbous moon will float near the bright star Regulus, the brightest star in Leo the Lion. They’ll be visible until a few hours before sunrise.

Two dots for the moon on April 17 and 18 and a small dot for Regulus.

Moon at apogee April 20

The moon will reach apogee – its farthest distance from Earth in its elliptical orbit around Earth – at 2 UTC on April 20, 2024 (9 p.m. CDT on April 19), when it’s 252,042 miles (405,623 kilometers) away.

Overnight April 21-22: Lyrid meteor shower

Overnight tonight, the Lyrid meteor shower peaks. But the moon is nearly full, hiding all but the brightest meteors in its glare. Diehards will be watching in the moonlight. Should you? Even one bright meteor – streaking along in the glare of the bright moon – would make it all worthwhile. Tips for watching a meteor shower in moonlight here.

Chart showing constellation Lyra and radial arrows from meteor shower radiant point near it.

Lyrid meteors radiate from near the bright star Vega in the constellation Lyra the Harp. You don’t need to identify Vega or Lyra in order to watch the Lyrid meteor shower. But you do need to know when the radiant rises, in this case in the northeast before midnight. That’s why the Lyrids are typically best between midnight and dawn. You’ll see the most meteors after the radiant has come over the horizon. The meteors radiate from there but will appear unexpectedly, in any and all parts of the sky. Image via EarthSky.

April 22 evening: Moon near Spica

On the evening of April 22, 2024, the fat waxing gibbous moon will hang near the bright star Spica in Virgo the Maiden. They’ll rise before sunset and be visible until sunrise.

A large white dot for the moon near a small dot for Spica on April 22.

April evenings: Can you still see Jupiter?

For the first three months of April, Jupiter appears low in the west shortly after sunset. But during the month’s final week, it lies too low in the bright evening twilight to be easily seen. It’ll be challenging to spot.

White dots for Jupiter and the Pleiades in April 2024.

April 23: Full moon near Spica

The full moon will glow brightly near the bright star Spica in Virgo the Maiden. The full moon occurs at 23:49 UTC (6:49 p.m. CDT) on April 23, 2024. It’ll be visible all night.

A large white dot for the moon near a small dot for Spica on April 23.

April 26 and 27 mornings: Moon near Antares

On the mornings of April 26 and 27, 2024, the waning gibbous moon will lie close to the bright star Antares in Scorpius the Scorpion. They’ll be visible from early morning until dawn. Also, skywatchers in Asia and Africa will see the moon pass in front of – or occult – Antares near 21 UTC on April 26.

White dots for the moon on two days with a red dot for Antares.

The Big Dipper and Leo the Lion

April is a great time to look up overhead in the evening sky and find the well-known pattern of stars we call the Big Dipper. It’s an asterism – or obvious pattern of stars – and part of the constellation Ursa Major the Great Bear. Also, you can find the constellation Leo the Lion. Leo has another well-known asterism known as the Sickle. The Sickle looks like a backward question mark that is punctuated by the bright star Regulus. In fact, the Big Dipper can help you locate Leo and the Sickle. An imaginary line drawn southward from the pointer stars in the Big Dipper – the two outer stars in the Dipper’s bowl – points toward Leo the Lion.

Stars of the Big Dipper and Leo the Lion with a line from the Pointers to Leo.

The Big Dipper and Polaris

Plus, the Big Dipper can direct you to find Polaris, the North Pole Star. The two outer stars in the bowl of the Dipper point to Polaris. It’s at the end of the handle of Ursa Minor the Little Bear, commonly known as the Little Dipper. Look for the Big and Little Dippers high in the northern sky on spring evenings. This view is for the Northern Hemisphere.

The Big and Little Dipper with arrow showing how 2 stars from the Big Dipper point to Polaris.

Cancer the Crab

Cancer the Crab, with its Beehive star cluster, needs a dark sky to be seen. It lies between the Gemini twin stars Castor and Pollux, and the bright star Regulus in Leo the Lion.

Once you’ve found Cancer – if your sky is dark – you can see the wonderful open star cluster called the Beehive. It contains some 1,000 stars.

Star chart: upside down Y shape for constellation Cancer, with other labeled stars and small dots for cluster.

April evenings: Jupiter

Jupiter appears low in the west shortly after sunset in the first three weeks of April. During the month’s final week, it lies too low in the bright evening twilight to be easily seen. At the beginning of the month, Jupiter sets about three hours after sunset. At month’s end, Jupiter lies low in the evening twilight and may be challenging to spot. Jupiter will lie near the delicate Pleiades star cluster.

White dots for Jupiter and the Pleiades in April 2024.

April mornings: Mars and Saturn

Mars and Saturn lie low in the morning twilight in April 2024. They shine with similar brightness and have a close pairing on the mornings of April 10 and 11. Saturn will climb a bit higher as the month goes on, and Mars will not move as much on the sky’s dome. By month’s end, Saturn will rise about two hours before sunrise and Mars will follow it about an hour later. Both planets will be easier to find in the coming months as they climb out of the morning glare.

Dots and arrows showing path of Mars and Saturn in the month of April.

Where are Venus and Mercury?

Venus is too close to the sun to be visible this month, and it’ll emerge in the evening sky around the beginning of August. Mercury will disappear from the bright evening twilight at the beginning of April and return to the morning sky in May.

Sky dome maps for visible planets and night sky

The sky dome maps come from master astronomy chart-maker Guy Ottewell. You’ll find charts like these for every month of 2024 in his Astronomical Calendar.

Circle constellations, planets, the moon, the Milky Way and celestial lines.

Here is the sky dome view for April 2024. It shows what is above the horizon at mid-evening for mid-northern latitudes. The view may vary depending on your location. Image via Guy Ottewell’s 2024 Astronomical Calendar.

Heliocentric solar system visible planets and more

The sun-centered charts come from Guy Ottewell. You’ll find charts like these for every month of 2024 in his Astronomical Calendar.

Circle with sun at center, planets around, and zodiac names on outer edge.

NASA to Launch Sounding Rockets into Moon’s Shadow During Solar Eclipse

NASA will launch three sounding rockets during the total solar eclipse on April 8, 2024, to study how Earth’s upper atmosphere is affected when sunlight momentarily dims over a portion of the planet.

The Atmospheric Perturbations around Eclipse Path (APEP) sounding rockets will launch from NASA’s Wallops Flight Facility in Virginia to study the disturbances in the ionosphere created when the Moon eclipses the Sun. The sounding rockets had been previously launched and successfully recovered from White Sands Test Facility in New Mexico, during the October 2023 annular solar eclipse. They have been refurbished with new instrumentation and will be relaunched in April 2024. The mission is led by Aroh Barjatya, a professor of engineering physics at Embry-Riddle Aeronautical University in Florida, where he directs the Space and Atmospheric Instrumentation Lab.

https://science.nasa.gov/solar-system/skywatching/nasa-to-launch-sounding-rockets-into-moons-shadow-during-solar-eclipse/

Notice the Westward Shift of Orion and all the Stars

Originally published by EarthSky.

We in the Northern Hemisphere think of Orion as a winter constellation. As our northern spring arrives – around late March and early April – we see Orion shifting into the sunset glare. That’s happening because Earth is a planet, moving in orbit around a star.

Westward shift of Orion

If you’re out on an evening walk in late March or early April, notice this seasonal aspect of the night sky. The famous constellation Orion the Hunter – an easy-to-spot star pattern in January and February – now seems to have moved and turned considerably. It’s very low in the western part of the sky when the sun goes down.

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Orion will soon disappear into the sun’s glare. Orion, like all the stars and constellations, shifts westward as the seasons pass. Unless they’re in the far northern or southern sky – and so circumpolar – all stars and constellations spend some portion of each year hidden in the sun’s glare.

All stars move westward in a single night

All the stars and their constellations also move westward in the course of a single night. Orion is no exception. That motion, though, is due to Earth’s spin.

But the seasonal disappearance of Orion – its sinking into the sunset glare during the northern spring months (southern fall months) – is something else. It’s as if we’re riding on a carousel through space – spinning, yes – but also the entire structure is moving. That is, Earth is moving in orbit around the sun. As we move in orbit, our night sky points out in different directions – toward different parts of the Milky Way galaxy – at different times of year.

Earth’s motion in orbit brings the sun between us and Orion at this same time each year.

Circular panorama of most of night sky scattered with stars and constellations.

We in the Northern Hemisphere think of Orion as a winter constellation. As our northern spring arrives – around late March and early April – we see Orion shifting into the sunset glare. That’s happening because Earth is a planet, moving in orbit around a star.

When will you see it last?

Exactly when Orion will disappear from your evening sky – into the sunset – depends on your latitude. The farther south you are, the longer you can see Orion. But for the central U.S., Orion is lost in the sun’s glare by early to mid-May (depending on how carefully you look for it).

And for all of us in the U.S., Orion is gone by the time of the summer solstice in June.

If you want to notice the westward shift of the constellations due to the passage of the seasons, be sure to watch at the same time every night. If you want to watch their westward shift throughout the night, just pull up a lawn chair and watch.

Either way, you can easily notice Orion moving steadily westward.

Earth from space with detailed continents, seas, and clouds.

The westward shift of the sky throughout the night is due to Earth’s spin under the stars. Meanwhile, the westward shift of the stars throughout the seasons is due to Earth’s motion in orbit around the sun. Earth’s motion in orbit causes our night sky to point outward toward an ever-shifting panorama of the galaxy. Image via NASA/ NOAA/ GSFC/ Suomi NPP/ VIIRS/ Norman Kuring.

Bottom line: Why the constellation Orion – and all the stars – shift westward as the seasons pass

Eclipse Day Comet Pons-Brooks! Favorite photos here

Originally published by EarthSky.

Eclipse Day Comet Pons-Brooks at Deep Creek Lake, MD

Rui Santos in Leiria, Portugal, captured this image of Comet Pons-Brooks on March 13, 2024. This is the comet you might see in the daytime sky, near the sun in total eclipse, on April 8. View a chart below. Rui wrote: “I felt amazed by the sight of the comet, its tail stretching majestically across the sky. It’s a scene that seems to transcend time and space.” Thank you, Rui! We’ve been getting some beautiful images of this comet from our talented community of photographers.

Have you seen Comet Pons-Brooks yet? This fuzzy ball of ice and dust is making its way toward the sun. Its closest approach to the sun will be on April 21. So it’ll be near the sun in our sky on eclipse day, April 8. Read about seeing the comet on eclipse day here. With the help of binoculars or a telescope, you can currently spot this comet in the evening sky now, in the northwest shortly after sunset. It’s been getting brighter! It might also become visible under dark skies to the unaided eye!

If you don’t live near dark skies or are battling clouds, you can see the comet right here, in beautiful images from the EarthSky community.

Star chart showing the eclipsed sun and Venus below it. Jupiter and the comet are above them.

During the total solar eclipse on April 8, 2024, the sky will darken enough that you should be able to see Venus and Jupiter. Comet Pons-Brooks will be close to Jupiter. Image via Stellarium/ Kelly Kizer Whitt. See Comet Pons-Brooks on eclipse day!

Comet Pons-Brooks and the Andromeda galaxy

Currently, the comet is hanging out in the constellation Andromeda. It appeared near the Andromeda galaxy in our sky, and astrophotographers captured some great shots of them together!

Comet Pons-Brooks: Dark, starry sky with 3 bright dots at the bottom left. The have fuzzy tails. At the top right, there is a yellowish disk labeled "M31".

Basudeb Chakrabarti and Samit Saha from Gharwan, Himachal Pradesh, India, shared this image of Comet Pons-Brooks from March 7 to March 9, 2024, with the Andromeda galaxy. Stunning! Thank you.

 

Bright, green dot with a fuzzy tail at bottom left. Yellowish streak at top left, and yellowish disk at top right. Trees and mountain in the background.

Osama Fathi at the Black Desert, Egypt, captured Comet Pons-Brooks, the Andromeda galaxy, and a meteor on March 8, 2024! All in 1. Thank you, Osama.

 

Bright dot with a faint tail at the bottom left. There is a yellowish disk at the top right. There are mountains in the background and a starry dark sky.

Basudeb Chakrabarti from Gharwan, Himachal Pradesh, India, shared this image captured by Samit Raz Saha on March 7, 2024. Basudeb wrote: “Currently located in the Andromeda constellation, comet 12P/Pons-Brooks is 247,124,592 kilometers (153,000,000 miles) away from Earth. Being at a dark location, Samit Raz Saha had the opportunity to capture this magnificent comet along with the Andromeda galaxy. I sincerely thank Samit Saha for giving me the opportunity to post process the data.” Thank you both!

Will you see Comet Pons-Brooks during the eclipse?

Comet Pons-Brooks visits the inner solar system every 71 years. Its next perihelion (when it’s closest to the sun) will be on April 21, 2024. That will put the comet fairly close to the sun during the total solar eclipse of April 8, 2024. But will you see the comet during the eclipse? And should you even try to look for it?

More images of the comet and galaxy

A comet on the left side and a spiral galaxy on the right side of a starfield.

Steven Bellavia in Southold, New York, captured this view of Comet Pons-Brooks and the Andromeda galaxy on March 11, 2024. Steven wrote: “Although the comet is only 250 million kilometers (155 million miles) from Earth, with Andromeda 23 trillion kilometers (14 trillion miles) distant, they are now sharing the same part of the sky.” Thank you, Steven!

 

A tree with fog and long-tailed comet above, and oblique view of a glowing galaxy near the top.

Petr Horálek in Revuca, Slovakia, captured Comet Pons-Brooks on March 5, 2024. Petr also captured the Andromeda galaxy along with “a distant tree, the fog illuminated by the passing cars.” Thank you. Petr!

 

Mountains in the horizon, dense clouds above them. There are 2 dots above the clouds, 1 labeled "12P/Pons-Brooks" and the other "M31".

Paolo Bardelli at Campo dei Fiori, Varese, Italy, shared this image of the comet and M31, the Andromeda galaxy, on March 7, 2024. Paolo wrote: “A finally successful attempt to photograph Comet 12P/Pons-Brooks during a rare evening, quite cloud-free, in a period characterized by an infinite passage of cloud fronts …” Thank you, Paolo!

More images of the comet

Starry sky, darker at the top right and brighter at the bottom left. There is a little, green dot in the middle of the image.

Radu Anghel from Ivanesti, Romania, captured this image on March 9, 2024. Radu wrote: “If it is a weekend with clear skies and a comet is close by, at the limit of the unaided-eye visibility, there is no other choice but to answer the call for astrophotography! Last evening I drove for more than an hour and a half to a place with Bortle 4 skies, just perfect for another comet image on my humble collection.” Wonderful! Thank you.

 

A comet with a green and round fuzzy head with a thin tail flowing away in a field of tiny scattered stars.

Steven Bellavia in Southold, New York, captured this image of Comet Pons-Brooks on February 25, 2024. Steven wrote: “This comet might be visible to the unaided eye during the total solar eclipse, being 24 degrees east of the sun and only 6 degrees west of Jupiter.” Thank you, Steven!

Bottom line: Have you seen Comet Pons-Brooks already? If not, here are some beautiful images from our talented community of photographers. Enjoy them!

Best Sky Scenes of 2024: What not to miss!

Originally published by EarthSky.

Best sky scenes of 2024: What not to miss at Deep Creek Lake, MD

2024 will be the year of the sun. Experts are predicting the peak of the sun’s 11-year cycle of activity for 2024. Plus, for us in North America, a total solar eclipse will take place on April 8, 2024. Learn more about it and some of the other best sky scenes of 2024, below. Fred Espenak shot the images for this composite of a total solar eclipse in Jalu, Libya, on March 29, 2016. The USPS used this image to create a postage stamp! Image via Fred Espenak/ Astropixels.

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.

January 8 and 9: Venus and friends

Star chart showing 2 crescent moons with Venus above and Mercury lower down.

The thin crescent moon will be near the red star Antares – the brightest star in Scorpius the Scorpion – on the morning of January 8. Venus is the brilliant point of light nearby, and the much dimmer Mercury will pop above the southeastern horizon before the sun rises. On the following morning, the moon hovers just above the horizon and close to Mercury. Chart by John Jardine Goss/ EarthSky.

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

Star chart showing Mercury as a bigger then smaller dot with an arrow showing it looping up and then downward.

Between March 22 and 25, Mercury makes a grand appearance in the western sky shortly after sunset. Chart by John Jardine Goss/ EarthSky.

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

A chart showing the moon blocking part of the sun, and below blocking part, then all, then part of the sun again.

In the afternoon of April 8, the moon slides in front of the sun giving a solar eclipse. A partial eclipse occurs for the entire US, but along a very specific swath, a total eclipse takes place. Always use proper filters when directly viewing the sun! Chart by John Jardine Goss/ EarthSky.

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!

Map of North America with parallel lines annotated with the percent of the sun that will be hidden during the eclipse.

This map shows how much of the sun will be in eclipse by location on April 8, 2024. Image via GreatAmericanEclipse.com. Used with permission.

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

Star chart with 2 crescent moons, plus 2 star clusters and Jupiter.

Jupiter, the Pleiades, the Hyades and the crescent moon create 2024’s most captivating scene on the evenings of April 10 and 11. Chart by John Jardine Goss/ EarthSky.

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

Star chart showing a crescent moon next to the dot of Mercury.

On the evening of July 7, the thin crescent moon floats immediately above little Mercury in the west shortly after sunset. Chart by John Jardine Goss/ EarthSky.

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.

A circle showing a binocular view with a crescent moon inside and a dot for Mercury.

Binoculars will help you enjoy the scene. Mercury will lie in the same field as the moon. Chart by John Jardine Goss/ EarthSky.

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

Star chart showing 2 crescent moons, Jupiter, Mars and the Head of Taurus the Bull.

In the early morning hours of July 30 and 31, the crescent moon joins Mars, Jupiter, the Pleiades, Aldebaranand the Hyades for a dramatic scene. Chart by John Jardine Goss/ EarthSky.

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

Dots for the constellation Cassiopeia with streaks showing the Perseid meteors.

After 11 p.m. on August 11, look to the northeast for upwards of 50 meteors per hour. It continues until dawn on the morning of August 12. Chart by John Jardine Goss/ EarthSky.

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

Star chart showing a red dot for Mars very close to a larger white dot for Jupiter and the V-shape of the head of Taurus the Bull nearby.

Red Mars narrowly misses bright Jupiter in the early morning hours of August 14. Look in the east for this planetary conjunction. Chart by John Jardine Goss/ EarthSky.

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.

A circle showing a binocular view of Jupiter with Mars shown as red dots moving past Jupiter.

Binoculars will help you see Mars pass bright Jupiter from August 10 through August 18. They’ll be at their closest to each other in the early morning hours of August 14. Chart by John Jardine Goss/ EarthSky.

Late August mornings: 6 planets before sunrise

Chart showing a green arcing line along a wide horizon showing the planets Mercury, Mars, Jupiter, Uranus, Neptune, Saturn and the moon with labels.

We can always find the planets lying along the ecliptic, which is the plane of our solar system. But often, some of the planets are in the morning sky, while others are in the evening sky, and still others are too close to the sun to see at all. On late August mornings, all the planets – except Venus – appear in the morning sky. Mars, Jupiter and Saturn will be easy. Can you challenge yourself to spot the rest? Chart via John Jardine Goss/ EarthSky.

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

Star chart for 3 days and 3 months showing a crescent moon near the white dot that is Venus.

In the southwest in the early evening hours of October 5, November 4, and December 4, the waxing crescent moon will glow next to brilliant Venus. Chart by John Jardine Goss/ EarthSky.

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

Star chart showing a comet with tail pointing away from the horizon for 2 dates, 1 closer to the horizon and 1 higher up.

If we are fortunate, a comet will grace our sky from October 14 to 24. Look to the west shortly after sunset for Comet Tsuchinshan–ATLAS. Chart by John Jardine Goss/ EarthSky.

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

Circle showing a binocular view with a dot for Venus near a blob labeled M8.

An hour after sunset on November 12, look at brilliant Venus through binoculars. It shines in the southwest. Above it in the same field lies the star-forming nebula M8, the Lagoon Nebula. Chart by John Jardine Goss/ EarthSky.

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

Star chart showing a red dot for Mars near a yellow ring labeled Beehive.

Looking southwest early on the morning of December 5, red Mars tangles with the Beehive star cluster. The twin stars of Gemini, Castor, and Pollux, lie nearby. Chart by John Jardine Goss/ EarthSky.

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.

Binocular view of Mars and the Beehive on December 5. Mars looks red and is at the top. The Beehive looks like a group of white dots.

In the morning on December 5, binoculars will help show bright Mars approaching the much dimmer Beehive star cluster. Chart by John Jardine Goss/ EarthSky.

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!

 

December full moon – Long Night Moon – mimics the June sun

Originally published by EarthSky.

December full moon – Long Night Moon – mimics the June sun at Deep Creek Lake, MD

The December full moon will light up the sky on the evening of December 26, 2023. The twin stars of Castor and Pollux twinkle nearby. Chart via 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.

December full moon: Diagram of Earth with moon and sun on opposite sides.

At full moon, the sun, Earth and moon align in space, with Earth in the middle. The moon’s day side – its fully lighted hemisphere – directly faces us. Chart via John Jardine Goss/ EarthSky.

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.

2 panels, left showing summer and winter sun paths, right showing matching moon paths.
The high arc across the sky of the late December full moon closely matches that of the June sun. The low arc of the December sun closely matches that of the June full moon.

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.

Arrow through lined-up moon and Earth pointing toward zodiac location labeled Gemini.

The December 2023 full moon occurs on the overnight of December 26 and lies in the constellation Gemini the Twins.

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.

Orion the Hunter and the Milky Way on December evenings

Originally published by EarthSky.

Orion the Hunter and the Milky Way on December evenings at Deep Creek Lake, MD

On December and January evenings, you’ll find a faint band – what we in the Northern Hemisphere call the “winter” Milky Way – stretching up from the horizon and running through the constellation Orion the Hunter. Notice Orion’s 3 Belt stars. They’re easy to spot in the sky. But you’ll need a dark sky to see the Milky Way.

Orion the Hunter on December evenings

Tonight, or any December evening, find the famous constellation Orion the Hunter. It’s bright and can be seen from inside smaller cities. And the three stars that makeup Orion’s Belt – in a short, straight row at the Hunter’s midsection – are very noticeable. If you have a dark sky, you can see something else: the starry band of the Milky Way – the edgewise view of our home galaxy – running behind Orion.

As seen from the Northern Hemisphere, after Orion rises, the three stars of Orion’s Belt jut more or less straight up from the horizon. Look on either side of the Belt stars for two very bright stars. One is the reddish star Betelgeuse. The other is bright, blue-white Rigel.

Throughout December, the constellation Orion is well up by mid-evening (by that we mean by midway between your local sunset and your local midnight). Like all of the starry sky, as Earth moves around the sun, Orion rises earlier each evening. So, by late December, Orion will be seen at nightfall or early evening. That’s true for both the Southern and Northern Hemispheres.

Orion is a summer constellation for the Southern Hemisphere.

But we in the Northern Hemisphere associate Orion with winter nights. That’s because this constellation is up throughout our long December and January nights.

Large array of 8 bright stars, blue-white except one reddish, in star field.

Orion the Hunter, captured by astrophotographer Alan Dyer. Rigel appears in the lower right of the constellation. Contrast its bluish-white light with that of reddish Betelgeuse in the upper left. Image via Alan Dyer/ AmazingSKY.com. Used with permission.

Use Orion to find the Milky Way

Because so many people are familiar with Orion, this constellation is a great jumping off spot for finding the starry pathway of the Milky Way. You’ll need a dark sky to see the hazy arc of stars running behind the bright red star Betelgeuse.

Looking at the Milky Way in our sky is looking edgewise into the disk of our galaxy. We see the galaxy as the combined glow of billions of stars. You might know that – in the month of August – the Milky Way appears broad and bright during the evening hours. At that time of year, in the evening, all of us on Earth are gazing toward the star-rich center of the galaxy.

Now Earth has traveled in its orbit around the sun, and our evening sky is pointing out in a different direction. If you see the Milky Way behind the constellation Orion this month, you might think it’s very faint in contrast to the August Milky Way. It is fainter, because now we’re looking toward the galaxy’s outer edge. There are fewer stars between us and intergalactic space.

Orion is easy to spot

At least part of Orion is visible from anywhere on the globe. It’s visible in the evening sky for Northern Hemisphere observers from late autumn through early spring. On the other hand, it’s visible in the summer evening sky from the Southern Hemisphere.

Star chart: constellation Orion above constellation Monoceros, with 5 stars labeled and faint gray band.

Here’s Orion higher in the sky, later at night in December, with the faint constellation Monoceros the Unicorn, plus the bright stars Sirius and Procyon. If you have a dark sky, you’ll find the faint winter Milky Way running behind them all.

Wide array of bright but slightly fuzzy bright stars, mostly blue-white but one reddish, over dark landscape.

View at EarthSky Community Photos. | Sergei Timofeevski shared this image from November 13, 2023. Sergei wrote: “The constellation Orion the Hunter and the star Sirius rising just above the eastern horizon in the Anza-Borrego Desert State Park, California.” Thank you, Sergei! See the orangish star marking one of Orion’s shoulders? That’s the star Betelgeuse.

Bottom line: You can find one of the most famous constellations – Orion the Hunter – plus see the Milky Way tonight.

Look for Mercury after sunset, early December 2023

Originally published by EarthSky.

Slanted green line of ecliptic through twilight, with dot near horizon labeled Mercury.On December 4, Mercury reaches its farthest angular distance from the sun, known as greatest eastern elongation. On this date, it lies low in the southwest. Chart via John Jardine Goss/ EarthSky.

Mercury will reach its greatest elongation – its greatest apparent distance from the sun on the sky’s dome for this evening apparition – on December 4, 2023.

Mercury after sunset in late 2023

Where to look: Look west, in the sunset direction – shortly after sunset – for Mercury. The sun’s innermost planet will be challenging, even when Mercury is farthest from the sunset, and even for the more favored view from the Southern Hemisphere.
Greatest elongation: Mercury is farthest from the sun on ou4 sky’s dome – at greatest elongation – at 14 UTC on December 4, 2023 (8 a.m. CDT on December 4). At that time, Mercury is 21 degrees from the sun in our sky.
Brightness: Mercury was bright when it emerged in the evening sky during the second week of November. At that time, it was shining at -0.5 magnitude. At greatest elongation, Mercury shines only slightly more faintly at magnitude -0.3. It’s still brighter than most stars! In the evenings after greatest elongation, the innermost planet will rapidly fade as it sweeps up from behind Earth, in orbit around the sun, causing its illuminated side, or day side, to turn away from us. It’ll probably disappear by mid-December 2023 and will reach inferior conjunction – when it will pass between Earth and the sun – on December 22.
Through a telescope: Mercury will appear about 62% illuminated, at greatest elongation. It’ll measure 6.7 arcseconds across.
Constellation: Mercury will lie in front of the constellation Sagittarius the Archer at this elongation. Doubtless, most of the stars in this constellation will be lost in the twilight.
Note: As the innermost planet, Mercury is tied to the sun in our sky. As a result, it never ventures very far above the horizon after sunset. So as soon as the sun disappears below your horizon, your clock starts ticking. Will you see the glowing point of light that is Mercury before it drops below the horizon, following the setting sun?

Diagram: Earth and Mercury orbits with sun in middle and 2 red lines of sight from the Earth to Mercury and the sun.At greatest elongation, Mercury is to one side of the sun and is at its greatest distance from the sun on our sky’s dome. Mercury reaches greatest eastern (evening) elongation from the sun on December 4, 2023. It is 21 degrees from the sun in the evening sky. Chart via John Jardine Goss/ EarthSky.

Finder charts for Northern Hemisphere evenings

Very low white dot for Mercury beside teapot-shaped group of stars along a green ecliptic line.For viewers in the Northern Hemisphere, Mercury will lie just above the horizon in the bright twilight shortly after sunset in the second half of November 2023. The Teapot asterism of Sagittarius is nearby but it will be difficult to spot in the bright evening twilight. Chart via John Jardine Goss/ EarthSky.

Mercury in December, Northern HemisphereFor viewers in the Northern Hemisphere, Mercury will lie just above the horizon in the bright twilight shortly after sunset in the first half of December 2023. Chart via John Jardine Goss/ EarthSky.

Moon December 14 and 15.Viewers with a low southwestern horizon and clear skies will spot the very thin crescent moon floating in the bright twilight shortly after sunset on December 14 and 15, 2023. Mercury will lie to the moon’s lower right, very close to the horizon. Chart via John Jardine Goss/ EarthSky.

Finder charts for November Southern Hemisphere evenings

Low white dot for Mercury below teapot-shaped group of stars along a green ecliptic line.During the second half of November 2023, Mercury will lie low in the west below the Teapot asterism of Sagittarius shortly after sunset. Chart via John Jardine Goss/ EarthSky.

Mercury in December, Southern HemisphereFor viewers in the Southern Hemisphere, during the first half of December 2023, Mercury lies low in the west immediately below the Teapot asterism of Sagittarius shortly after sunset. Chart via John Jardine Goss/ EarthSky.

Mercury events in 2023 and 2024

Note: Times are in UTC

Jan 7, 2023: Inferior conjunction (races between Earth and sun)
Jan 30, 2023: Greatest elongation (morning)
Mar 17, 2023: Superior conjunction (passes behind sun from Earth)
Apr 11, 2023: Greatest elongation (evening)
May 1, 2023: Inferior conjunction (races between Earth and sun)
May 29, 2023: Greatest elongation (morning)
Jul 1, 2023: Superior conjunction (passes behind sun from Earth)
Aug 10, 2023: Greatest elongation (evening)
Sep 6, 2023: Inferior conjunction (races between Earth and sun)
Sep 22, 2023: Greatest elongation (morning)
Oct 20, 2023: Superior conjunction (passes behind sun from Earth)
Dec 4, 2023: Greatest elongation (evening)
Dec 22, 2023: Inferior conjunction (races between Earth and sun)

Jan 12, 2024: Greatest elongation (morning)
Feb 28, 2024: Superior conjunction (passes behind sun from Earth)
Mar 24, 2024: Greatest elongation (evening)
Apr 11, 2024: Inferior conjunction (races between Earth and sun)
May 9, 2024: Greatest elongation (morning)
Jun 14, 2024: Superior conjunction (passes behind sun from Earth)
Jul 22, 2024: Greatest elongation (evening)
Aug 19, 2024: Inferior conjunction (races between Earth and sun)
Sep 5, 2024: Greatest elongation (morning)
Sep 30, 2024: Superior conjunction (passes behind sun from Earth)
Nov 16, 2024: Greatest elongation (evening)
Dec 5, 2024: Inferior conjunction (races between Earth and sun)
Dec 25, 2024: Greatest elongation (morning)

Heliocentric view of Mercury December 2023

Circle with sun at center, planets around, and zodiac names on outer edge.Heliocentric view of solar system, December 2023. Chart via Guy Ottewell Used with permission.

A comparison of elongations

The farthest from the sun that Mercury can ever appear on the sky’s dome is about 28 degrees. And the least distance is around 18 degrees.

Also, elongations are better or worse depending on the time of year they occur. So in 2023, the Southern Hemisphere had the best evening elongation of Mercury in August 2023. And the Northern Hemisphere had the best evening apparition in April.

In the autumn for either hemisphere, the ecliptic – or path of the sun, moon and planets – makes a narrow angle to the horizon in the evening. But it makes a steep slant, nearly perpendicular, in the morning. So, in autumn from either hemisphere, morning elongations of Mercury are best. That’s when Mercury appears higher above the horizon and farther from the glow of the sun. However, evening elongations in autumn are harder to see.

In the spring for either hemisphere, the situation reverses. The ecliptic and horizon meet at a sharper angle on spring evenings and a narrower angle on spring mornings. So, in springtime for either hemisphere, evening elongations of Mercury are best. Meanwhile, morning elongations in springtime are harder to see.

Chart with row of alternating light blue and gray arcs, each with a date and height in degrees.Mercury elongations compared. Here, gray areas represent evening apparitions (eastward elongation). Blue areas represent morning apparitions (westward elongation). The top figures are the maximum elongations, reached at the top dates shown beneath. Curves show the altitude of the planet above the horizon at sunrise or sunset, for latitude 40 degrees north (thick line) and 35 degrees south (thin). Maxima are reached at the parenthesized dates below (40 degrees north in bold type). Chart via Guy Ottewell’s 2023 Astronomical Calendar. Used with permission.

More Mercury elongation comparisons for 2023

Annotated sky chart with arced rows of dots for positions of planet, and dashed line for celestial equator.Mercury’s greatest evening elongations in 2023 from the Northern Hemisphere as viewed through a powerful telescope. The planet images are at the 1st, 11th, and 21st of each month. Dots show the actual positions of the planet for every day. Chart via Guy Ottewell. Used with permission.

Sky chart with constellations, arc-shaped dotted planet paths, and objects labeled.Mercury’s greatest evening elongations in 2023 from the Southern Hemisphere as viewed through a powerful telescope. The planet images are at the 1st, 11th, and 21st of each month. Dots show the actual positions of the planet for every day. Chart via Guy Ottewell. Used with permission.

Mercury photos from our community

Sunset with tall, narrow, bare trees to left and label of Mercury on small dot in blue twilight sky.Joel Weatherly in Edmonton, Alberta, Canada, took this image on April 23, 2022. Joel wrote: “Lonely little Mercury is making an appearance in our evening skies. Despite being elusive, it was easy to see without optical aid once sighted.” Thank you, Joel!

Silhouette of lifeguard tower in the foreground, crescent moon and Mercury in an orange and blue twilight sky.View at EarthSky Community Photos. | Chix RC captured this image on January 3, 2022, from Hermosa Beach, California. See Mercury to the upper right of the crescent? Chix wrote: “A faint young moon at 1% illumination and Mercury.” Thank you, Chix!

Crescent moon, 2 labeled dots (Mercury and Venus) in blue and orange sky over a lighted suspension bridge.Alexander Krivenyhev of the website WorldTimZone.com captured this photo of the moon together with Mercury and Venus on May 13, 2021, from Newport, Rhode Island. Thank you, Alexander!

Bottom line: Mercury is visible in the evening sky. Look in the west as the sky is darkening. The planet will reach its greatest elongation overnight on December 4, 2023.

See Orion’s Belt as a Celestial Bridge between Hemispheres

Originally published by EarthSky.

See Orion’s Belt as a Celestial Bridge between Hemispheres at Deep Creek Lake, MD

Look east in the mid-evenings of November for the constellation Orion the Hunter. The 3 stars at the midsection of the Hunter are known as Orion’s Belt. As a matter of fact, the star Mintaka lies on the celestial equator, a line around the entire sky above Earth’s equator. Hence the legend of Orion’s Belt as a celestial bridge. Chart via Chelynne Campion/ EarthSky.

Look for Mintaka in Orion’s Belt

See the three stars at Orion the Hunter’s midsection? These stars are Alnitak, Alnilam and Mintaka. In fact, they’re very noticeable and famous in many cultures as Orion’s Belt. In the Southern Hemisphere, the Aymara people of Bolivia, Peru, and Chile saw the Belt as a celestial bridge or a staircase to the world of souls. But astronomers see the Belt as a type of bridge, too. These stars link the sky’s northern and southern hemispheres.

Consider Mintaka, which is the Belt’s westernmost star. It sits almost directly astride the celestial equator: the projection of Earth’s equator onto the stellar sphere.

So where can you find Mintaka and the constellation Orion? In late November, from around the world, Orion rises in your eastern sky around 9 p.m. and climbs highest for the night around 1 to 2 a.m. local time.

When dawn is breaking, or about to break, say around 5 to 6 a.m., the Hunter sits low in your western sky.

Star chart showing the constellation Orion with longitude/latitude grid laid over it.

The constellation Orion the Hunter straddles the celestial equator, which is indicated by the horizontal line marked as 0o (0 degrees). Since the celestial equator intersects horizons all over the world at points due east and due west, you can use the star Mintaka – the one directly on the celestial equator – to find those cardinal directions in your sky. Image via ESO/ IAU/ Sky & Telescope.

Mintaka shines on the celestial equator

Mintaka’s location on the celestial equator makes it a good guidepost for finding directions here on Earth. That is, Mintaka and the other stars of the Celestial Bridge are visible worldwide. From all over the world, Mintaka rises due east, sets due west, and remains in the sky for 12 hours. It climbs to its highest point in the sky midway between rising and setting.

When it’s highest in the sky, if this star shines at your zenith (your straight-overhead point), then you must be at the equator.

If this star shines in the southern half of your sky, then you must be north of the equator.

If this star shines in the northern half of your sky, then you must be south of the equator.

The story of the Celestial Bridge is one of many about the constellation Orion. That’s because it’s so noticeable on our sky’s dome. So watch for it when you’re outside one evening soon!

Chart showing Earth inside a large translucent sphere with lines for celestial equator, celestial poles and ecliptic.

The celestial equator is an imaginary great circle on the dome of Earth’s sky drawn directly above the equator of the Earth. How you see the celestial equator in your sky depends on your latitude. But, because it’s above Earth’s equator, no matter where you are on the globe, the celestial equator intersects your horizon at points due east and due west. The ecliptic is the apparent path of the sun through the sky. Image via NASA.

Bottom line: The indigenous Aymara people of the Andes and Altiplano regions of South America see the famous sky feature we know as Orion’s Belt as a celestial bridge between the sky’s Northern and Southern Hemispheres. In fact, its westernmost star, Mintaka, lies directly on the celestial equator.

Watch the Night Sky!

Originally published by Maryland Department of Natural Resources.

Watch the Night Sky at Deep Creek Lake, MD

Celestial gifts arrive just in time for the holidays, giving skywatchers the chance to wish upon dozens of shooting stars in the coming days and weeks. The Leonids are active until December 2, peaking November 17-18. The Geminids, known for their reliably bright and intensely colored meteors, will be active starting Nov. 19 and are slated to wrap up on Christmas Eve, according to the American Meteor Society. The moon doesn’t appear to be a spoiler this year, so viewers will be able to watch the dazzling display without distractions. With little moonlight interruption, those with an eye to the sky could see up to 150 meteors per hour.

See the Summer Triangle in Northern Autumn

Originally published by EarthSky.

See the Summer Triangle in Northern Autumn at Deep Creek Lake, MD

The Summer Triangle is a famous asterism, consisting of 3 bright stars overhead in northern summer. But you can also easily see it through the northern autumn, and even into winter.

The Summer Triangle and its 3 stars

The Summer Triangle is the signature star formation in the Northern Hemisphere’s summer sky. However, as the September equinox comes and goes – and as the weeks of autumn begin to slide by – you’ll still notice this famous trio of stars. So, look for the Summer Triangle after dark in early November. It will actually continue to shine after dark in November and December, and is even visible still in January. Look for it tonight in the early evening, high in your western sky.

By the way, the Summer Triangle isn’t a constellation. It’s an asterism, or an obvious pattern or group of stars with a popular name. In fact, the Summer Triangle consists of three bright stars in three separate constellations. The bright star Vega is in Lyra the Harp. Deneb is in Cygnus the Swan. And Altair is in Aquila the Eagle.

In the month of June – around the June solstice – the Summer Triangle pops out in the east as darkness falls and shines all night long. But now – after sunset in November – the Summer Triangle appears high in the western evening sky. As evening deepens, the Summer Triangle descends westward, with all three of its stars staying above the horizon until mid-to-late evening.

Altair – the Summer Triangle’s southernmost star – will set around 10 to 11 p.m. tonight at mid-northern latitudes. Notice where you see the Summer Triangle at a given time this evening. The Summer Triangle will return to this same place in the sky some four minutes earlier with each passing day, or two hours earlier with each passing month.

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

Look for Orion, too

Then as the Summer Triangle sinks close to the western horizon around mid-evening, turn around to see Orion the Hunter – the signpost constellation of winter – rising in the east.

Bottom line: Look westward this evening for the three brilliant stars of the humongous Summer Triangle: Vega, Deneb and Altair. In fact, you can still see the Summer Triangle through January.

Watch the Sky for the Comet Lemmon!

Originally published by Maryland Department of Natural Resources and Astronomy.

Watch the Sky for the Comet Lemmon at Deep Creek Lake, MD

💫 Watch the Sky! Comet Lemmon is brightening quickly as it approaches a close pass of the earth this month, according to astronomy.com. The first half of November is the best time to catch comet H2 Lemmon. Currently flying beneath the curved handle of the Big Dipper, Lemmon is highest in the early-morning hours before sunrise. Skywatchers should step outside any time after about 5 A.M. while the sky is still dark. Look north, where you’ll see the Big Dipper standing upright on the end of its handle. Right where the handle kinks is the famous naked-eye double of Mizar and Alcor. From this pair, swing binoculars or a telescope about 6° south-southwest to land smack dab on Lemmon.

Brightest star, Sirius, high on October mornings

Originally published by EarthSky.

Brightest star, Sirius: Star chart with Orion, arrow from 3-star Belt to lone star Sirius below.
No matter when you see it in the sky, Orion’s Belt always points to the sky’s brightest star, Sirius. On October mornings, Sirius and Orion can be found in the south before dawn. Southern Hemisphere? Look north and turn this chart upside down.

Watch for the brightest star, Sirius

The planet Venus is up at dawn now. And it’s very bright, much brighter than any other planet or star. But – at this time of year – we always get questions about another bright object in the dawn sky. Andy wrote:

Early this morning, looking south, I saw a beautiful star, bright and multicolored … Can you identify it for me?

And Paula wrote:

This morning two of us got up early. We found a pulsing star straight down the sky below Orion’s Belt. It was pulsing the colors of green, yellow, blue and red like a strobe light. I will search for it every morning as it was so enchanting.

If you’re up before daybreak on these October mornings, take a moment to see this star, which is the sky’s brightest star, Sirius. This star is so brilliant that you can even see it from a light-polluted city. And you can see it if you stay up late, too! It’s rising in the middle of the night now, as seen from around the globe, and is high in the sky – at its best – by dawn.

Want a specific view from your location on the globe? Visit Stellarium and enter your location.

What is that bright twinkling star?

This star is enchanting, so much so that – every year, beginning in Northern Hemisphere autumn – we get many, many questions about a multicolored star twinkling in the southeastern to southern sky after midnight. This star typically turns out to be Sirius, which is in the constellation Canis Major the Greater Dog and is sometimes called the Dog Star.

Why does Sirius twinkle so much?

Sirius appears to flash different colors when it’s low in the sky. Really, all the stars are flashing different colors, because light is composed of all the colors of a rainbow, and the journey through our atmosphere breaks starlight into its component colors via refraction. But you don’t notice the colors of the other stars much, because they’re not as bright as Sirius, which is the brightest star visible from anywhere on Earth.

Since our atmosphere is causing the light to break into its colors, and since Sirius is often seen low in the sky now (where you are peering at it through a thicker layer of atmosphere than when it’s overhead), the flashing colors of Sirius are very obvious. When Sirius is higher in the sky – which it is close to dawn in the month of October – or in the evening sky in January and February – you’ll find that Sirius shines with a steadier, whiter light.

So, on these October mornings, watch as Sirius winks at you in the wee hours before dawn!

Long green line of a meteor above a beach, with constellation Orion and bright star Sirius below it.
View at EarthSky Community Photos. | Daniel Friedman captured this shot from Montauk, New York, on December 13, 2020. Note bright Sirius is on the left, and Orion’s Belt points to it. Thank you, Daniel!

Bottom line: We get many questions about a bright, colorful, twinkling star on these October mornings. It’s the star Sirius in the constellation Canis Major, and the brightest star in the sky. Plus, you’ll know it’s Sirius, because Orion’s Belt always points to it.

Watch the Sky: The Annual Solar Eclipse October 14, 2023

Watch the Sky :The Annual Solar Eclipse October 14, 2023 at Deep Creek Lake, MD

Watch the Sky! It’s an exciting time for skywatchers as the “Ring of Fire” solar eclipse takes place on Saturday, October 14. A solar eclipse occurs when the moon passes over the sun, partially or completely blocking the sun’s rays. Although Maryland residents will only be able to see a partial eclipse, 30-40% depending on your location, it’s still an incredible sight – just remember to protect your eyes. Even viewing a partial eclipse requires some form of eye protection; it is never safe to look directly at the sun.

What star in the northeast flashes colorfully? It’s Capella!

Star in the northeast: Chart showing the constellation Auriga with stars and other objects labeled.

The bright star Capella in the constellation Auriga the Charioteer is the star in the northeast that flashes red, green and blue. Capella is bright at magnitude 0.24 and it’s low in the northeastern sky in the evenings. Around October in the Northern Hemisphere, many people look at this star and wonder if they’re seeing a UFO. To be sure you’ve found Capella, look for a little triangle of stars nearby. Capella is sometimes called the Goat Star, and this little asterism is called The Kids. 

Capella is the colorful, twinkling star in the northeast

This evening, check out one of the flashiest stars in the sky. It’s so bright that every year in northern autumn, we get questions from people in the Northern Hemisphere who see a star twinkling with colorful flashes. It lies low in the northeastern sky at nightfall or early evening as seen from mid-northern locations. That star is Capella. The reason it’s so flashy is because it’s a bright star shining near the horizon, its light coming to us through our thick atmosphere. The wavering air makes its point of light jump around, split into colors and appear to flash.

If you could travel to it in space, you’d find that Capella is really two golden stars, both with roughly the same surface temperature as our local star, the sun … but both larger and brighter than our sun.

Capella is in the constellation Auriga the Charioteer. Since antiquity, Capella’s nickname has been the Goat Star. You might pick it out just by gazing northeastward from a Northern Hemisphere latitude during the evening hours in October. Capella climbs upward through the night, and this month soars high overhead in the wee hours before dawn.

Why stars twinkle or flash

So, Capella is a golden point of light that flashes red and green when it’s low in the sky. Why does it do that?

The reality is that every star in the sky undergoes the same process as Capella when it twinkles. That is, every star’s light must shine through Earth’s atmosphere before reaching our eyes. But not every star flashes as noticeably as Capella. The flashes happen because Capella is low in the sky in the evening at this time of year. And, when you look at an object low in the sky, you’re looking through more atmosphere than when the same object is overhead.

The atmosphere splits or refracts the star’s light, just as a prism splits sunlight.

So that’s where Capella’s red and green flashes are coming from – not from the star itself – but from the refraction of its light by our atmosphere. When you see Capella higher in the sky, you’ll find that these glints of color will disappear.

By the way, why are these flashes of color so noticeable with Capella? The reason is simply that it’s a bright star. It’s the sixth brightest star in Earth’s sky, not including our sun.

Here are 2 other flashing stars of autumn

If the flashy star you’re seeing doesn’t seem to be Capella (wrong time, wrong location?), here are a couple other options. Arcturus is in the northwest at this time of year. Follow the curving handle of the Big Dipper toward the horizon, and if it hits the star you’re wondering about, then you’re looking at Arcturus in Boötes.

Another option is Sirius. If you’re waking before dawn this time of year, you’ll find Sirius toward the south. Check out the maps below to see which star is twinkling at you.

Chart of the Big Dipper with a line following the Dipper's handle to Arcturus.

Look northwest soon after sunset in October to find the star Arcturus in the constellation Boötes and the Big Dipper asterism. The curve in the Dipper’s handle always points to Arcturus, one of autumn’s 3 flashiest stars. Just be sure to look not long after nightfall. Unlike Capella, which ascends in the northeastern sky throughout the evening, Arcturus sets not long after sunset. 

 

Chart of Orion with a line following Orion's Belt to Sirius.

Look southward before dawn to see the star Sirius in October. At this time of year, we get many, many questions about a multicolored star twinkling in the southeastern to southern sky after midnight. This star typically turns out to be Sirius, which is in the constellation Canis Major the Greater Dog and is sometimes called the Dog Star. Notice that a line from Orion’s Belt points to Sirius.

Bottom line: If you’re in Earth’s Northern Hemisphere and see a bright star twinkling with red and green flashes low in the northeast on October evenings, it’s probably Capella.