A Spring Triangle of stars heralds the season

The Spring Triangle is an asterism – a noticeable sky pattern – with 3 bright stars at its corners. The stars are Arcturus, Spica and Regulus. All 3 stars are in different constellations. Image via EarthSky.

The Spring Triangle heralds warmer weather

Around the time of the March equinox, a trio of stars rises in the east after dark. You can notice this pattern if you look for it. The Spring Triangle announces the slide into shorter nights and warmer weather for the Northern Hemisphere. The pattern consists of three stars in three separate constellations. The stars are Regulus in Leo the Lion, Arcturus in Boötes the Herdsman and – last to rise above the March horizon – Spica in Virgo the Maiden.

These three bright stars create a narrow pyramid stretching up from the horizon.

The Spring Triangle is entirely above the horizon before midnight in March. And by early April, all three stars are visible by mid-evening (midway between sundown and midnight).

Once you come to know it, when you see the Spring Triangle stars are up, you can almost feel the warm springtime air.

The Spring Triangle is an asterism

Like the sky’s other seasonal shapes (for instance, the Summer Triangle and Winter Circle or Hexagon), the Spring Triangle isn’t a constellation. It’s not one of the 88 regions of the sky officially recognized as constellations by the International Astronomical Union.

Instead, it’s an asterism, an unofficial but recognizable pattern of stars that can be in one constellation or in multiple constellations. Asterisms are what many of us would pick out as constellations, if we didn’t know any constellations. That’s because they’re often the sky’s most recognizable patterns.

Let’s look at how to find these stars so we can watch them move across the night sky.

Leo the Lion’s brightest star is Regulus. It’s the dot at the bottom of the backward question mark known as the Sickle. Chart via EarthSky.

Regulus

As soon as it’s dark around the March equinox, look for a bright yellowish star twinkling above the eastern horizon. That’s Regulus, and it’s easy to confirm if you’ve spotted the right star. If the star you’re targeting marks the period in a backward question mark pattern of stars, you’ve got it. This question mark shape is another asterism known as the Sickle in Leo. The curve of the question mark traces the head of the lion and Regulus is the Lion’s Heart.

When we look at Regulus, we only see one star, but it’s actually a four-star system. From about 79 light-years away, the light from the four stars makes one point of light in the night sky. The brightest star in this system is a yellow supergiant about four times the size of our sun.

Arcturus and its constellation Boötes the Herdsman. Boötes has the shape of a kite. Arcturus is at the point where you’d attach a tail. You can see it on spring evenings in the Northern Hemisphere. Chart via EarthSky.

Arcturus

Next up is Arcturus, the brightest star of the three in the Spring Triangle. For those at northerly latitudes, Arcturus is the second-brightest star visible on the sky’s dome, after Sirius, which is currently in the southwestern sky. (Those at more southerly latitudes, like the southern U.S., can see the sky’s actual second-brightest star, Canopus, in the south.) Arcturus is a gorgeous old red giant about 37 light-years away. Billions of years in the future, when the sun has burned up its own hydrogen fuel supply, it will turn into a star like the type Arcturus is now.

The constellation Virgo the Maiden is easy to find using the Big Dipper and arcing to Arcturus in Boötes, then speeding on down toward Spica, Virgo’s brightest star. Image via the International Astronomical Union (IAU).

Spica

If Arcturus has risen, Spica is not far behind. Look for Spica lower in the sky than Arcturus – and father toward the south, or right – of the others. From a distance of 250 light-years away, Spica appears to us on Earth to be a lone bluish-white star in a quiet region of the sky. But Spica consists of two stars and maybe more. The pair are both larger and hotter than our sun, and they’re separated by only 11 million miles (less than 18 million km). They orbit their common center of gravity in only four days.

A triangle inside the triangle

If you can spot the Spring Triangle, you may notice there’s a second triangle inside the larger triangle. The smaller triangle excludes Regulus but includes yellowish Denebola, a double star about 36 light-years away that marks the Lion’s tail. Denebola is the second brightest star in Leo. To see this second triangle, look at the chart below.

The Small Spring Triangle includes Denebola instead of Regulus. Image via EarthSky.

The Spring Triangle is less attention-grabbing than the Winter Circle (or Hexagon) and the Summer Triangle. If you’re having trouble finding it, there’s another way. Use the Big Dipper for extra help.

Finding the Spring Triangle

Toward the north, look for the Big Dipper, called the Plough in the United Kingdom. This time of year, by mid-evening, it’s ascending in the northeast. If you draw a line from the two stars at the end of the Dipper’s bowl or blade – Dubhe and Merak – and extend it toward the south, you’ll reach Regulus.

Then, follow the curve of the Dipper’s handle away from the bowl to arc to Arcturus and continue the line downward to speed on down to Spica.

Surprisingly enough, the Spring Triangle is bigger than its more famous summertime cousin, and it’s almost as big across as the Winter Hexagon. Yet it’s not one of the best-known star patterns.

Once you’ve found the Spring Triangle, you’ll enjoy it year after year. Maybe because it appears as spring arrives, this pattern seems full of optimism for good things to come!

Find the Spring Triangle using the Big Dipper as a guide. Image via EarthSky.

And it covers a large area of the sky

As you can tell from this allsky image of the night sky, the Spring Triangle covers a large area of the sky. Image via WyoAstro allsky camera. Used with permission.

Bottom Line: Look for a sign of the changing seasons in the heavens as the Spring Triangle – made up of the bright stars Regulus, Arcturus and Spica – rises above the horizon in the east over the next couple of months.

Meet Regulus, Leo the Lion’s Heart

Arcturus, the brightest star of the northern sky

Spica, the bright beacon of Virgo, is 2 stars

The post A Spring Triangle of stars heralds the season first appeared on EarthSky.

from EarthSky https://ift.tt/S8pyarL

The Spring Triangle is an asterism – a noticeable sky pattern – with 3 bright stars at its corners. The stars are Arcturus, Spica and Regulus. All 3 stars are in different constellations. Image via EarthSky.

The Spring Triangle heralds warmer weather

Around the time of the March equinox, a trio of stars rises in the east after dark. You can notice this pattern if you look for it. The Spring Triangle announces the slide into shorter nights and warmer weather for the Northern Hemisphere. The pattern consists of three stars in three separate constellations. The stars are Regulus in Leo the Lion, Arcturus in Boötes the Herdsman and – last to rise above the March horizon – Spica in Virgo the Maiden.

These three bright stars create a narrow pyramid stretching up from the horizon.

The Spring Triangle is entirely above the horizon before midnight in March. And by early April, all three stars are visible by mid-evening (midway between sundown and midnight).

Once you come to know it, when you see the Spring Triangle stars are up, you can almost feel the warm springtime air.

The Spring Triangle is an asterism

Like the sky’s other seasonal shapes (for instance, the Summer Triangle and Winter Circle or Hexagon), the Spring Triangle isn’t a constellation. It’s not one of the 88 regions of the sky officially recognized as constellations by the International Astronomical Union.

Instead, it’s an asterism, an unofficial but recognizable pattern of stars that can be in one constellation or in multiple constellations. Asterisms are what many of us would pick out as constellations, if we didn’t know any constellations. That’s because they’re often the sky’s most recognizable patterns.

Let’s look at how to find these stars so we can watch them move across the night sky.

Leo the Lion’s brightest star is Regulus. It’s the dot at the bottom of the backward question mark known as the Sickle. Chart via EarthSky.

Regulus

As soon as it’s dark around the March equinox, look for a bright yellowish star twinkling above the eastern horizon. That’s Regulus, and it’s easy to confirm if you’ve spotted the right star. If the star you’re targeting marks the period in a backward question mark pattern of stars, you’ve got it. This question mark shape is another asterism known as the Sickle in Leo. The curve of the question mark traces the head of the lion and Regulus is the Lion’s Heart.

When we look at Regulus, we only see one star, but it’s actually a four-star system. From about 79 light-years away, the light from the four stars makes one point of light in the night sky. The brightest star in this system is a yellow supergiant about four times the size of our sun.

Arcturus and its constellation Boötes the Herdsman. Boötes has the shape of a kite. Arcturus is at the point where you’d attach a tail. You can see it on spring evenings in the Northern Hemisphere. Chart via EarthSky.

Arcturus

Next up is Arcturus, the brightest star of the three in the Spring Triangle. For those at northerly latitudes, Arcturus is the second-brightest star visible on the sky’s dome, after Sirius, which is currently in the southwestern sky. (Those at more southerly latitudes, like the southern U.S., can see the sky’s actual second-brightest star, Canopus, in the south.) Arcturus is a gorgeous old red giant about 37 light-years away. Billions of years in the future, when the sun has burned up its own hydrogen fuel supply, it will turn into a star like the type Arcturus is now.

The constellation Virgo the Maiden is easy to find using the Big Dipper and arcing to Arcturus in Boötes, then speeding on down toward Spica, Virgo’s brightest star. Image via the International Astronomical Union (IAU).

Spica

If Arcturus has risen, Spica is not far behind. Look for Spica lower in the sky than Arcturus – and father toward the south, or right – of the others. From a distance of 250 light-years away, Spica appears to us on Earth to be a lone bluish-white star in a quiet region of the sky. But Spica consists of two stars and maybe more. The pair are both larger and hotter than our sun, and they’re separated by only 11 million miles (less than 18 million km). They orbit their common center of gravity in only four days.

A triangle inside the triangle

If you can spot the Spring Triangle, you may notice there’s a second triangle inside the larger triangle. The smaller triangle excludes Regulus but includes yellowish Denebola, a double star about 36 light-years away that marks the Lion’s tail. Denebola is the second brightest star in Leo. To see this second triangle, look at the chart below.

The Small Spring Triangle includes Denebola instead of Regulus. Image via EarthSky.

The Spring Triangle is less attention-grabbing than the Winter Circle (or Hexagon) and the Summer Triangle. If you’re having trouble finding it, there’s another way. Use the Big Dipper for extra help.

Finding the Spring Triangle

Toward the north, look for the Big Dipper, called the Plough in the United Kingdom. This time of year, by mid-evening, it’s ascending in the northeast. If you draw a line from the two stars at the end of the Dipper’s bowl or blade – Dubhe and Merak – and extend it toward the south, you’ll reach Regulus.

Then, follow the curve of the Dipper’s handle away from the bowl to arc to Arcturus and continue the line downward to speed on down to Spica.

Surprisingly enough, the Spring Triangle is bigger than its more famous summertime cousin, and it’s almost as big across as the Winter Hexagon. Yet it’s not one of the best-known star patterns.

Once you’ve found the Spring Triangle, you’ll enjoy it year after year. Maybe because it appears as spring arrives, this pattern seems full of optimism for good things to come!

Find the Spring Triangle using the Big Dipper as a guide. Image via EarthSky.

And it covers a large area of the sky

As you can tell from this allsky image of the night sky, the Spring Triangle covers a large area of the sky. Image via WyoAstro allsky camera. Used with permission.

Bottom Line: Look for a sign of the changing seasons in the heavens as the Spring Triangle – made up of the bright stars Regulus, Arcturus and Spica – rises above the horizon in the east over the next couple of months.

Meet Regulus, Leo the Lion’s Heart

Arcturus, the brightest star of the northern sky

Spica, the bright beacon of Virgo, is 2 stars

The post A Spring Triangle of stars heralds the season first appeared on EarthSky.

from EarthSky https://ift.tt/S8pyarL

More moons for Jupiter and Saturn! New totals here

Saturn now officially has 285 moons! This animation, from Tony Dunn at Orbitsimulator.com, shows some of the previously known moons in white and newly discovered moons in red, as they orbit Saturn. On March 16, 2026, the Minor Planet Center announced 11 more moons for Saturn and 4 more moons for Jupiter. Image via Tony Dunn. Used with permission.

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More moons for Jupiter and Saturn!

On March 16, 2026, the Minor Planet Center announced an additional 11 moons for Saturn, bringing its total to a whopping 285. Plus, Jupiter’s moon count has finally cracked 100, with the addition of four newly discovered moons. Jupiter’s grand total now stands at 101.

The newly discovered moons are all quite small, at least as far as moons are concerned. That’s why they haven’t been discovered until now. These faint, distant space rocks are around 2 miles wide (3 km) with magnitudes of +25 to +27. The lower the number, the brighter it is. And truly bright objects even have negative numbers, like the sun (-26) and Venus (-4). So these moons are extraordinarily faint. They also orbit far from their planet, making them harder to track down.

In fact, the moons of Saturn are so spread out, they span the width of about five full Earth moons as seen from our location here on Earth. So, as you look toward the ringed planet, imagine its entourage of satellites extending for vast distances on either side of it.

As telescopes and observation methods improve, astronomers keep finding more family members at Jupiter and Saturn. In fact, it was just last March that the Minor Planet Center announced a staggering 128 additional moons for Saturn.

This illustration shows how much of the sky our moon takes up in comparison to Saturn’s 285 moons. Saturn’s moons cover approximately 5 times the amount of sky as our moon does from our viewpoint on Earth. Image via Tony Dunn/ Orbitsimulator.com. Used with permission.

Observations of the moons

These moons are only “new” in that they are new to us. They were too small and dim for astronomers to spot previously. Astronomers made the discoveries by combining past observations with new observations. They were looking for objects that moved. And there will probably be a number of new discoveries to come!

The Vera C. Rubin Observatory went online in June of 2025. Since then, it’s been issuing alerts to astronomers of the changes it spots in the sky. These changes are often the dimming or brightening stars and small objects on the move. Rubin sees the tiny changes the objects make from night to night. On February 24 alone, Rubin issued 800,000 alerts.

Names for the new moons

Only the largest of Jupiter’s and Saturn’s moon have proper names, such as Ganymede and Titan. The majority of these two planets’ many moons are quite small and dim. For example, out of Saturn’s 285 moons, only 64 have proper names. The organization that would be in charge of naming these moons is the International Astronomical Union’s Committee for Planetary System Nomenclature. And its rule is that:

… a Jovian or Saturnian satellite with an absolute magnitude fainter than 16.5 should only be named if it is of special scientific interest.

The new discoveries have magnitudes of 25 to 27. So these small, irregular moons are known by designations instead of names.

Jupiter’s 4 new moons are:

• S/2011 J 4
• S/2011 J 5
• S/2018 J 5
• S/2024 J 1

And Saturn’s 11 new moons are:

• S/2020 S 45
• S/2020 S 46
• S/2020 S 47
• S/2020 S 48
• S/2023 S 51
• S/2023 S 52
• S/2023 S 53
• S/2023 S 54
• S/2023 S 55
• S/2023 S 56
• S/2023 S 57

For now, Saturn holds a substantial lead on Jupiter for most moons in our solar system.

Only the largest and brightest moons of Jupiter and Saturn get proper names. For example, Jupiter’s largest moon, Ganymede, has a proper name. The Cassini spacecraft captured this image of the pair on December 3, 2000. Image via NASA.

Bottom line: The Minor Planet Center announced 11 more moons for Saturn and 4 more moons for Jupiter on March 16, 2026. Their new grand totals? Saturn has 285 and Jupiter has 101.

Via Minor Planet Center

The post More moons for Jupiter and Saturn! New totals here first appeared on EarthSky.

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Saturn now officially has 285 moons! This animation, from Tony Dunn at Orbitsimulator.com, shows some of the previously known moons in white and newly discovered moons in red, as they orbit Saturn. On March 16, 2026, the Minor Planet Center announced 11 more moons for Saturn and 4 more moons for Jupiter. Image via Tony Dunn. Used with permission.

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More moons for Jupiter and Saturn!

On March 16, 2026, the Minor Planet Center announced an additional 11 moons for Saturn, bringing its total to a whopping 285. Plus, Jupiter’s moon count has finally cracked 100, with the addition of four newly discovered moons. Jupiter’s grand total now stands at 101.

The newly discovered moons are all quite small, at least as far as moons are concerned. That’s why they haven’t been discovered until now. These faint, distant space rocks are around 2 miles wide (3 km) with magnitudes of +25 to +27. The lower the number, the brighter it is. And truly bright objects even have negative numbers, like the sun (-26) and Venus (-4). So these moons are extraordinarily faint. They also orbit far from their planet, making them harder to track down.

In fact, the moons of Saturn are so spread out, they span the width of about five full Earth moons as seen from our location here on Earth. So, as you look toward the ringed planet, imagine its entourage of satellites extending for vast distances on either side of it.

As telescopes and observation methods improve, astronomers keep finding more family members at Jupiter and Saturn. In fact, it was just last March that the Minor Planet Center announced a staggering 128 additional moons for Saturn.

This illustration shows how much of the sky our moon takes up in comparison to Saturn’s 285 moons. Saturn’s moons cover approximately 5 times the amount of sky as our moon does from our viewpoint on Earth. Image via Tony Dunn/ Orbitsimulator.com. Used with permission.

Observations of the moons

These moons are only “new” in that they are new to us. They were too small and dim for astronomers to spot previously. Astronomers made the discoveries by combining past observations with new observations. They were looking for objects that moved. And there will probably be a number of new discoveries to come!

The Vera C. Rubin Observatory went online in June of 2025. Since then, it’s been issuing alerts to astronomers of the changes it spots in the sky. These changes are often the dimming or brightening stars and small objects on the move. Rubin sees the tiny changes the objects make from night to night. On February 24 alone, Rubin issued 800,000 alerts.

Names for the new moons

Only the largest of Jupiter’s and Saturn’s moon have proper names, such as Ganymede and Titan. The majority of these two planets’ many moons are quite small and dim. For example, out of Saturn’s 285 moons, only 64 have proper names. The organization that would be in charge of naming these moons is the International Astronomical Union’s Committee for Planetary System Nomenclature. And its rule is that:

… a Jovian or Saturnian satellite with an absolute magnitude fainter than 16.5 should only be named if it is of special scientific interest.

The new discoveries have magnitudes of 25 to 27. So these small, irregular moons are known by designations instead of names.

Jupiter’s 4 new moons are:

• S/2011 J 4
• S/2011 J 5
• S/2018 J 5
• S/2024 J 1

And Saturn’s 11 new moons are:

• S/2020 S 45
• S/2020 S 46
• S/2020 S 47
• S/2020 S 48
• S/2023 S 51
• S/2023 S 52
• S/2023 S 53
• S/2023 S 54
• S/2023 S 55
• S/2023 S 56
• S/2023 S 57

For now, Saturn holds a substantial lead on Jupiter for most moons in our solar system.

Only the largest and brightest moons of Jupiter and Saturn get proper names. For example, Jupiter’s largest moon, Ganymede, has a proper name. The Cassini spacecraft captured this image of the pair on December 3, 2000. Image via NASA.

Bottom line: The Minor Planet Center announced 11 more moons for Saturn and 4 more moons for Jupiter on March 16, 2026. Their new grand totals? Saturn has 285 and Jupiter has 101.

Via Minor Planet Center

The post More moons for Jupiter and Saturn! New totals here first appeared on EarthSky.

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Equinox sun above horizon all day at the poles

The video above is from the South Pole during polar sunset in March 2022. That’s when the sun goes from having been up for 6 months to being down for the next 6 months. So, during the equinox, the sun scrapes along the horizon during the entire day. But did you know that the equinox sun looks exactly the same at both poles at the same time? Video via South Pole Telescope.

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An EarthSky reader sent us a question a while back – at the September equinox 2023 to be exact – to ask how an equinox looks at the North and South Poles. Would it, due to refraction, be above the horizon at both poles at the same time, and all day long? This turned into a delightful exchange of emails (we do love chatting with our readers!) where we mused on the topic of polar equinox. Our reader, Rod Cavanaugh, had it all figured out! He wanted to make sure his ideas were correct … and so they were.

Equinox sun at the North Pole

At the poles, the year can be divided into one night and one day, or rather, half a year of darkness and half a year of daylight. The transition between these two states of sun-presence on the sky occurs during the equinoxes. At the North Pole, the sun is below the horizon for the entire winter. During the March equinox, it pops above the horizon – polar sunrise – to then sit in the sky for the entire summer, higher and higher each day until we hit the summer solstice. So, during equinox day, it follows the horizon all day long.

Polar sunrise for South Pole in September, sunset in March

At the South Pole, it is the opposite: the sun has been above the horizon for half a year, and then, during the March equinox, the day transitions via polar sunset, into eternal (or, rather, half a year of) darkness.

So, half the sun is below the horizon and half is above it, at both poles. Or at least that is how it would look like without the Earth’s atmosphere.

Concordia station in Antarctica is not located on the South Pole, but near it. So they experience sunrise in August, not September, and have 4 months of darkness, not 6. Here, researchers celebrate the sunrise at Concordia research station on August 11, 2020. Read more about this image, which is via ESA.

The sun is above the horizon at both poles at the same time

But, here comes the surprise! Due to refraction, a sun on the horizon does not appear to be half below it and half above it, even though it geometrically would be. The atmosphere refracts the light that hits your eye, such that the sun appears to be about 1/2 a degree above the horizon at both places. Our reader, Rod Cavanaugh, wrote:

If the atmosphere’s refraction raises the sun about 1/2 a degree and the sun’s angular diameter is about 1/2 a degree, then at sunset the actual/geometric sun should be completely set at the time the apparent/refracted sun first touches the horizon.

But from the poles, the center of the sun should be exactly on the horizon at the equinox, so there should be a gap of 1/4 a degree between the apparent sun and the horizon, meaning the sun is completely above the horizon at both poles on the equinox.

When the sun is just below the horizon, refraction lifts it to appear just on top of it. The amount of refraction near the horizon is around 1/2 a degree, which also happens to be the sun’s apparent diameter. Image via Sciencia58/ Wikipedia (CC BY-SA 4.0).

Not only on the horizon, but above it

Rod asked if this seemingly counterintuitive situation is correct. And indeed, it is! A sun that sits 1/2 a degree (30 arcminutes) below the horizon is refracted 33 arcminutes. But the equinox sun is a bit higher (not below the horizon yet, but half above and half below). This means that there will be a gap between horizon and sun. The gap won’t be exactly 0.25 degrees, but the top will be refracted between 25 and 29 (we can assume 27) arcminutes, and the bottom part (0.25 degrees below horizon), about 31 arcminutes.

So, Rod’s thought experiment is correct. There will be a gap of about a quarter of a degree (about 15 arcminutes), so the sun will appear a bit above the horizon at both locations. Also, the sun will appear oval because the upper limb (edge) is refracted less than the lower.

Bottom line: We know the equinox sun rises due east and sets due west. But what happens at Earth’s poles? Turns out the North Pole sun is above the horizon all day long. And it looks exactly the same at the South Pole!

Atmospheric refraction explained

Watch the sunset at the South Pole on NOAA/ESRL’s South Pole Live Camera

The post Equinox sun above horizon all day at the poles first appeared on EarthSky.

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The video above is from the South Pole during polar sunset in March 2022. That’s when the sun goes from having been up for 6 months to being down for the next 6 months. So, during the equinox, the sun scrapes along the horizon during the entire day. But did you know that the equinox sun looks exactly the same at both poles at the same time? Video via South Pole Telescope.

You deserve a daily dose of good news. For the latest in science and the night sky, subscribe to EarthSky’s free daily newsletter.

An EarthSky reader sent us a question a while back – at the September equinox 2023 to be exact – to ask how an equinox looks at the North and South Poles. Would it, due to refraction, be above the horizon at both poles at the same time, and all day long? This turned into a delightful exchange of emails (we do love chatting with our readers!) where we mused on the topic of polar equinox. Our reader, Rod Cavanaugh, had it all figured out! He wanted to make sure his ideas were correct … and so they were.

Equinox sun at the North Pole

At the poles, the year can be divided into one night and one day, or rather, half a year of darkness and half a year of daylight. The transition between these two states of sun-presence on the sky occurs during the equinoxes. At the North Pole, the sun is below the horizon for the entire winter. During the March equinox, it pops above the horizon – polar sunrise – to then sit in the sky for the entire summer, higher and higher each day until we hit the summer solstice. So, during equinox day, it follows the horizon all day long.

Polar sunrise for South Pole in September, sunset in March

At the South Pole, it is the opposite: the sun has been above the horizon for half a year, and then, during the March equinox, the day transitions via polar sunset, into eternal (or, rather, half a year of) darkness.

So, half the sun is below the horizon and half is above it, at both poles. Or at least that is how it would look like without the Earth’s atmosphere.

Concordia station in Antarctica is not located on the South Pole, but near it. So they experience sunrise in August, not September, and have 4 months of darkness, not 6. Here, researchers celebrate the sunrise at Concordia research station on August 11, 2020. Read more about this image, which is via ESA.

The sun is above the horizon at both poles at the same time

But, here comes the surprise! Due to refraction, a sun on the horizon does not appear to be half below it and half above it, even though it geometrically would be. The atmosphere refracts the light that hits your eye, such that the sun appears to be about 1/2 a degree above the horizon at both places. Our reader, Rod Cavanaugh, wrote:

If the atmosphere’s refraction raises the sun about 1/2 a degree and the sun’s angular diameter is about 1/2 a degree, then at sunset the actual/geometric sun should be completely set at the time the apparent/refracted sun first touches the horizon.

But from the poles, the center of the sun should be exactly on the horizon at the equinox, so there should be a gap of 1/4 a degree between the apparent sun and the horizon, meaning the sun is completely above the horizon at both poles on the equinox.

When the sun is just below the horizon, refraction lifts it to appear just on top of it. The amount of refraction near the horizon is around 1/2 a degree, which also happens to be the sun’s apparent diameter. Image via Sciencia58/ Wikipedia (CC BY-SA 4.0).

Not only on the horizon, but above it

Rod asked if this seemingly counterintuitive situation is correct. And indeed, it is! A sun that sits 1/2 a degree (30 arcminutes) below the horizon is refracted 33 arcminutes. But the equinox sun is a bit higher (not below the horizon yet, but half above and half below). This means that there will be a gap between horizon and sun. The gap won’t be exactly 0.25 degrees, but the top will be refracted between 25 and 29 (we can assume 27) arcminutes, and the bottom part (0.25 degrees below horizon), about 31 arcminutes.

So, Rod’s thought experiment is correct. There will be a gap of about a quarter of a degree (about 15 arcminutes), so the sun will appear a bit above the horizon at both locations. Also, the sun will appear oval because the upper limb (edge) is refracted less than the lower.

Bottom line: We know the equinox sun rises due east and sets due west. But what happens at Earth’s poles? Turns out the North Pole sun is above the horizon all day long. And it looks exactly the same at the South Pole!

Atmospheric refraction explained

Watch the sunset at the South Pole on NOAA/ESRL’s South Pole Live Camera

The post Equinox sun above horizon all day at the poles first appeared on EarthSky.

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The equinox sun rises due east and sets due west

The March equinox will come on March 20, 2026.  At the equinoxes, the ecliptic and the celestial equator intersect. See the intersection point on this imaginary sphere, representing the dome of Earth’s sky? The celestial equator is directly above Earth’s equator. The ecliptic is the sun’s apparent path across our sky. And the celestial equator intersects your horizon at points due east and due west. That’s why – at every equinox, no matter where you are on the globe except the North and South Poles – the sun, on the celestial equator, rises due east and sets due west. Read more about the equinox sun below. Image via NASA.

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This year’s March equinox will happen on March 20, 2026, at 14:46 UTC (9:46 a.m. CDT).

The equinox sun rises due east and sets due west

It’s not true that day and night are precisely equal on the day of an equinox. But here’s an equinox fact that is true. The sun rises due east and sets due west at the equinox. It might seem counterintuitive. But it’s true no matter where you live on Earth (except at the North and South Poles). Here’s how to visualize it.

To understand the nearly due-east and due-west rising and setting of an equinox sun, you have to think of the reality of Earth in space. First think about why the sun’s path across our sky shifts from season to season. That’s because our world is tilted on its axis with respect to its orbit around the sun.

Now think about what an equinox is. It’s an event that happens on the imaginary dome of Earth’s sky. And it marks that special moment when the sun crosses the celestial equator going from one hemisphere to the other. Of course, it also represents a point in Earth’s orbit.

Our seasons result from the Earth’s rotational axis tilting 23.5 degrees out of the perpendicular to the ecliptic, or Earth’s orbital plane. Image via National Weather Service/ weather.gov.

The equinox sun crosses the celestial equator

The celestial equator is a great circle dividing the imaginary celestial sphere into its northern and southern hemispheres. Additionally, the celestial equator wraps the sky directly above Earth’s equator.

All these components are imaginary, yet what happens at every equinox is very real. In fact, it’s as real as the sun’s passage across the sky each day and as real as the change of seasons.

It’s the same all over the globe

So no matter where you are on Earth (except for the North and South Poles), you have a due east and due west point on your horizon. That point marks the intersection of your horizon with the celestial equator, the imaginary great circle above the true equator of Earth.

And that’s why the sun rises close to due east and sets close to due west, for all of us, at the equinox. The equinox sun is on the celestial equator. Which means, no matter where you are on Earth, the celestial equator intersects your horizon at due east and due west.

This fact makes the day of an equinox a good day for finding east and west from your yard or favorite site for watching the sky. Just go outside around sunset or sunrise and notice the location of the sun on the horizon with respect to familiar landmarks.

If you do this, you’ll be able to use those landmarks to find those cardinal directions in the weeks and months ahead. Plus, you’ll know those directions long after Earth has moved on in its orbit around the sun.

The history of the seasons

Our ancestors may not have understood the equinoxes and solstices as events that occur during Earth’s yearly orbit around the sun. But if they were observant – and some were very observant indeed – they surely marked the day of the equinox as being midway between the sun’s lowest path across the sky in winter and highest path across the sky in summer.

Now we can say with reasonably high accuracy that the sun rises due east and sets due west on the day of the equinox. And this is the same for everyone around the globe.

If you are seeking more precision for the sunrise/sunset direction in your part of the world, check out the altitude/azimuth for the sun via timeanddate.com.

View at EarthSky Community Photos. | How fast is daytime growing around the equinox? Rupesh Sangoi in Mumbai, India, captured separate images of the sunrise, showing the sun’s movement along the horizon, between the June and December solstices and on the equinoxes. Rupesh wrote: “Did this for over a year, at sunrise.” Glorious composite, Rupesh! Thank you.

Bottom line: The 2026 March equinox occurs at 14:46 UTC (9:46 p.m. CDT) on March 20, 2026. Read more about the March equinox.

Are day and night equal on the equinox?

It’s aurora season. Why more auroras at equinoxes?

Equinox sun above the horizon all day at the poles

The post The equinox sun rises due east and sets due west first appeared on EarthSky.

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The March equinox will come on March 20, 2026.  At the equinoxes, the ecliptic and the celestial equator intersect. See the intersection point on this imaginary sphere, representing the dome of Earth’s sky? The celestial equator is directly above Earth’s equator. The ecliptic is the sun’s apparent path across our sky. And the celestial equator intersects your horizon at points due east and due west. That’s why – at every equinox, no matter where you are on the globe except the North and South Poles – the sun, on the celestial equator, rises due east and sets due west. Read more about the equinox sun below. Image via NASA.

Science news, night sky events and beautiful photos, all in one place. Click here to subscribe to EarthSky’s free daily newsletter.

This year’s March equinox will happen on March 20, 2026, at 14:46 UTC (9:46 a.m. CDT).

The equinox sun rises due east and sets due west

It’s not true that day and night are precisely equal on the day of an equinox. But here’s an equinox fact that is true. The sun rises due east and sets due west at the equinox. It might seem counterintuitive. But it’s true no matter where you live on Earth (except at the North and South Poles). Here’s how to visualize it.

To understand the nearly due-east and due-west rising and setting of an equinox sun, you have to think of the reality of Earth in space. First think about why the sun’s path across our sky shifts from season to season. That’s because our world is tilted on its axis with respect to its orbit around the sun.

Now think about what an equinox is. It’s an event that happens on the imaginary dome of Earth’s sky. And it marks that special moment when the sun crosses the celestial equator going from one hemisphere to the other. Of course, it also represents a point in Earth’s orbit.

Our seasons result from the Earth’s rotational axis tilting 23.5 degrees out of the perpendicular to the ecliptic, or Earth’s orbital plane. Image via National Weather Service/ weather.gov.

The equinox sun crosses the celestial equator

The celestial equator is a great circle dividing the imaginary celestial sphere into its northern and southern hemispheres. Additionally, the celestial equator wraps the sky directly above Earth’s equator.

All these components are imaginary, yet what happens at every equinox is very real. In fact, it’s as real as the sun’s passage across the sky each day and as real as the change of seasons.

It’s the same all over the globe

So no matter where you are on Earth (except for the North and South Poles), you have a due east and due west point on your horizon. That point marks the intersection of your horizon with the celestial equator, the imaginary great circle above the true equator of Earth.

And that’s why the sun rises close to due east and sets close to due west, for all of us, at the equinox. The equinox sun is on the celestial equator. Which means, no matter where you are on Earth, the celestial equator intersects your horizon at due east and due west.

This fact makes the day of an equinox a good day for finding east and west from your yard or favorite site for watching the sky. Just go outside around sunset or sunrise and notice the location of the sun on the horizon with respect to familiar landmarks.

If you do this, you’ll be able to use those landmarks to find those cardinal directions in the weeks and months ahead. Plus, you’ll know those directions long after Earth has moved on in its orbit around the sun.

The history of the seasons

Our ancestors may not have understood the equinoxes and solstices as events that occur during Earth’s yearly orbit around the sun. But if they were observant – and some were very observant indeed – they surely marked the day of the equinox as being midway between the sun’s lowest path across the sky in winter and highest path across the sky in summer.

Now we can say with reasonably high accuracy that the sun rises due east and sets due west on the day of the equinox. And this is the same for everyone around the globe.

If you are seeking more precision for the sunrise/sunset direction in your part of the world, check out the altitude/azimuth for the sun via timeanddate.com.

View at EarthSky Community Photos. | How fast is daytime growing around the equinox? Rupesh Sangoi in Mumbai, India, captured separate images of the sunrise, showing the sun’s movement along the horizon, between the June and December solstices and on the equinoxes. Rupesh wrote: “Did this for over a year, at sunrise.” Glorious composite, Rupesh! Thank you.

Bottom line: The 2026 March equinox occurs at 14:46 UTC (9:46 p.m. CDT) on March 20, 2026. Read more about the March equinox.

Are day and night equal on the equinox?

It’s aurora season. Why more auroras at equinoxes?

Equinox sun above the horizon all day at the poles

The post The equinox sun rises due east and sets due west first appeared on EarthSky.

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Death Valley superbloom 2026! Best in a decade

View at EarthSky Community Photos. | Ross Stone in California captured the Death Valley superbloom on March 16, 2026. Ross wrote: ” field of desert gold wildflowers in full bloom near Badwater in Death Valley National Park.” Thank you, Ross!

You deserve a daily dose of good news. For the latest in science and the night sky, subscribe to EarthSky’s free daily newsletter.

Death Valley superbloom 2026

Death Valley National Park – the hottest and driest place in North America – is having a superbloom. 

The park normally sees about 2 inches (5 cm) of rain in a year. But it had more than a year’s worth of rain (2.5 inches, or 6 cm) between November 2025 and January 2026. 

The extra rain woke up dormant seeds. It’s given us the first superbloom in Death Valley since 2016.

As of mid-March, the superbloom is past peak, but there are still flowers to be seen! The National Park Service (NPS) announced current bloom locations (March 16, 2026):

• Badwater Rd (between CA190 and Sidewinder Canyon): Desert Gold, Phacelia, Mojave Star. Some flowers remain, most are setting seed
• Beatty Cutoff: Phacelia, Desert Gold, Gravel Ghost
• Panamint Valley: occasional Desert Gold patches; brittlebush by Father Crowley Vista

In early March, the NPS said:

We are having the best bloom year since 2016 and many sprouts have not yet flowered. The showy yellow desert gold is one of the most prominent flowers, but there are a large variety of other species blooming as well. Low-elevation flowers are blooming throughout the park and will likely persist until mid-late March, depending on the weather. Higher elevations will have blooms April-June.

The Death Valley superbloom is happening now. It’s the best display of spring wildflowers since 2016. Image via National Park Service.

@accuweather

The Death Valley superbloom is underway! ? Colorful flowers are blanketing parts of the hottest place in North America. Park officials say it’s the best superbloom since 2016.

? original sound – AccuWeather

A rare spectacle

Superblooms don’t happen on a schedule, but they occur about once a decade. The past superblooms have been in 2016, 2005 and 1998. The extra abundance of flowers can also attract more pollinators, so keep an eye out for more bees, butterflies, birds and more.

This rare and short-lived phenomenon is important to the desert ecosystem. The NPS said:

In Death Valley National park, most of the showy desert wildflowers are annuals, also referred to as ephemerals because they are short-lived. Oddly enough, this limited lifespan ensures survival here. Rather than struggle to stay alive during the desert’s most extreme conditions, annual wildflowers lie dormant as seeds. When enough rain finally does fall, the seeds quickly sprout, grow, bloom and go back to seed again before the dryness and heat returns. By blooming en masse during good years, wildflowers can attract large numbers of pollinators such as butterflies, moths, bees and hummingbirds that might not otherwise visit Death Valley.

View larger. | Death Valley wildflowers. Posted by the National Park Service in March 2026.

View at EarthSky Community Photos. | Ross Stone captured a rare sight of water in the basin at Death Valley National Park on March 15, 2026. Ross wrote: “Even though the temperatures are quickly rising in Death Valley, there is still a good amount of water in Lake Manly … Which makes it a fabulous place to people watch and take some excellent landscape photographs.” Thank you, Ross!

Are you planning to visit the park this spring?

Here’s what you need to know if you’re planning to visit the park this spring. First, be patient! There will be many others visiting also, but it’s a huge park with space for everyone. Traffic might be slow, but you will eventually get to that picture-perfect site.

To keep up-to-date on what’s blooming and where, visit the NPS website.

And, of course, don’t pick the wildflowers! Capture them only with your camera. And if you get a great photo, submit it to us!

2026 Death Valley superbloom

NATURE's WAY… Fighting Death With Color Energy! ??Death Valley Sees Its Most Spectacular Super Bloom In A Decade…

— Gaylan G. (@gaylan.bsky.social) 2026-03-08T17:43:58.284Z

1/x“Wildflowers, South Death Valley” — A flower-covered landscape.Is this a so-called “super bloom” year…more: gdanmitchell.com/2026/03/07/w…#deathvalley #wildflowers #superbloom #photo #photoOfTheDay #lensCulture #landscapePhotography #photographyLovers #naturePhotography #fineArtPhotography

— G Dan Mitchell | Photography (@gdanmitchell.com) 2026-03-07T15:51:39.664Z

Bottom line: A Death Valley superbloom erupted this spring. This rare event only happens about every decade. Read more about what flowers are blooming and where in Death Valley National Park.

Read more: What moves the sailing stones of Death Valley?

The post Death Valley superbloom 2026! Best in a decade first appeared on EarthSky.

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View at EarthSky Community Photos. | Ross Stone in California captured the Death Valley superbloom on March 16, 2026. Ross wrote: ” field of desert gold wildflowers in full bloom near Badwater in Death Valley National Park.” Thank you, Ross!

You deserve a daily dose of good news. For the latest in science and the night sky, subscribe to EarthSky’s free daily newsletter.

Death Valley superbloom 2026

Death Valley National Park – the hottest and driest place in North America – is having a superbloom. 

The park normally sees about 2 inches (5 cm) of rain in a year. But it had more than a year’s worth of rain (2.5 inches, or 6 cm) between November 2025 and January 2026. 

The extra rain woke up dormant seeds. It’s given us the first superbloom in Death Valley since 2016.

As of mid-March, the superbloom is past peak, but there are still flowers to be seen! The National Park Service (NPS) announced current bloom locations (March 16, 2026):

• Badwater Rd (between CA190 and Sidewinder Canyon): Desert Gold, Phacelia, Mojave Star. Some flowers remain, most are setting seed
• Beatty Cutoff: Phacelia, Desert Gold, Gravel Ghost
• Panamint Valley: occasional Desert Gold patches; brittlebush by Father Crowley Vista

In early March, the NPS said:

We are having the best bloom year since 2016 and many sprouts have not yet flowered. The showy yellow desert gold is one of the most prominent flowers, but there are a large variety of other species blooming as well. Low-elevation flowers are blooming throughout the park and will likely persist until mid-late March, depending on the weather. Higher elevations will have blooms April-June.

The Death Valley superbloom is happening now. It’s the best display of spring wildflowers since 2016. Image via National Park Service.

@accuweather

The Death Valley superbloom is underway! ? Colorful flowers are blanketing parts of the hottest place in North America. Park officials say it’s the best superbloom since 2016.

? original sound – AccuWeather

A rare spectacle

Superblooms don’t happen on a schedule, but they occur about once a decade. The past superblooms have been in 2016, 2005 and 1998. The extra abundance of flowers can also attract more pollinators, so keep an eye out for more bees, butterflies, birds and more.

This rare and short-lived phenomenon is important to the desert ecosystem. The NPS said:

In Death Valley National park, most of the showy desert wildflowers are annuals, also referred to as ephemerals because they are short-lived. Oddly enough, this limited lifespan ensures survival here. Rather than struggle to stay alive during the desert’s most extreme conditions, annual wildflowers lie dormant as seeds. When enough rain finally does fall, the seeds quickly sprout, grow, bloom and go back to seed again before the dryness and heat returns. By blooming en masse during good years, wildflowers can attract large numbers of pollinators such as butterflies, moths, bees and hummingbirds that might not otherwise visit Death Valley.

View larger. | Death Valley wildflowers. Posted by the National Park Service in March 2026.

View at EarthSky Community Photos. | Ross Stone captured a rare sight of water in the basin at Death Valley National Park on March 15, 2026. Ross wrote: “Even though the temperatures are quickly rising in Death Valley, there is still a good amount of water in Lake Manly … Which makes it a fabulous place to people watch and take some excellent landscape photographs.” Thank you, Ross!

Are you planning to visit the park this spring?

Here’s what you need to know if you’re planning to visit the park this spring. First, be patient! There will be many others visiting also, but it’s a huge park with space for everyone. Traffic might be slow, but you will eventually get to that picture-perfect site.

To keep up-to-date on what’s blooming and where, visit the NPS website.

And, of course, don’t pick the wildflowers! Capture them only with your camera. And if you get a great photo, submit it to us!

2026 Death Valley superbloom

NATURE's WAY… Fighting Death With Color Energy! ??Death Valley Sees Its Most Spectacular Super Bloom In A Decade…

— Gaylan G. (@gaylan.bsky.social) 2026-03-08T17:43:58.284Z

1/x“Wildflowers, South Death Valley” — A flower-covered landscape.Is this a so-called “super bloom” year…more: gdanmitchell.com/2026/03/07/w…#deathvalley #wildflowers #superbloom #photo #photoOfTheDay #lensCulture #landscapePhotography #photographyLovers #naturePhotography #fineArtPhotography

— G Dan Mitchell | Photography (@gdanmitchell.com) 2026-03-07T15:51:39.664Z

Bottom line: A Death Valley superbloom erupted this spring. This rare event only happens about every decade. Read more about what flowers are blooming and where in Death Valley National Park.

Read more: What moves the sailing stones of Death Valley?

The post Death Valley superbloom 2026! Best in a decade first appeared on EarthSky.

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Pyxis the Compass shines in the March night sky

Pyxis the Compass is considered a constellation of the Southern Hemisphere skies. But northerners at southerly latitudes can see it, too, on March evenings.

Science news, night sky events and beautiful photos, all in one place. Click here to subscribe to our free daily newsletter.

The constellation Pyxis the Compass

March is a good month to view the constellation Pyxis the Compass. That’s assuming you’re far enough south on Earth’s globe. Pyxis is one of the 14 constellations that the French astronomer Nicolas-Louis de Lacaille created in the 1700s. It represents a ship’s compass. Conveniently, this ship’s compass lies on our sky’s dome next to the three constellations, Puppis, Vela and Carina, elements that made up the former constellation of Argo Navis. That was the great starry Ship that once sailed the southern skies.

By the way, don’t confuse Pyxis the Compass with Circinus. That’s a different constellation that represents a drawing compass.

Pyxis lies southeast of Canis Major the Greater Dog, with its very bright star Sirius. From Sirius, look toward the east to the quiet part of the sky where Pyxis resides. See the photo below.

View at EarthSky Community Photos. | Prateek Pandey in Bhopal, India (23 degrees north latitude) captured this photo of Pyxis, Canis Major and Puppis. Pyxis is best viewed from the Southern Hemisphere. But it can be seen from southerly latitudes in the Northern Hemisphere, too. Thank you, Prateek!

The stars of Pyxis

The Alpha and Beta stars of Pyxis lie in the southern part of the constellation. More specifically, Alpha Pyxidis is magnitude 3.68 and lies 845 light-years away. Likewise, just over 2 degrees to the south is Beta Pyxidis at magnitude 3.97 and lying 388 light-years away.

In addition, both Alpha and Beta have faint star clusters lying a half degree to the northwest. Alpha’s star cluster is NGC 2658 at magnitude 9.2. And Beta’s star cluster is NGC 2635 at magnitude 11.2. So with this in mind, you’ll want binoculars or a telescope to track them down. In particular, NGC 2635 is a real challenge.

However, there are two other deep-sky targets in Pyxis that are somewhat brighter. First, there’s NGC 2627. It’s a magnitude 8.4 star cluster lying 3 1/2 degrees northwest of Alpha, or just 1/2 degree southwest of Zeta Pyxidis, a magnitude 4.86 star. Then, the second one lies in the southeast corner of the constellation. It’s NGC 2818, a planetary nebula shining at magnitude 11.6. Which we can see in the glorious Hubble photo, below.

The stars of Pyxis are difficult to see from a location with light pollution. For instance, Pyxis the Compass’s brightest star is a faint magnitude 3.68. Image via International Astronomical Union/ Wikimedia Commons (CC BY 3.0).

The Hubble Space Telescope took this shot of the planetary nebula NGC 2818 in Pyxis in 2009. Image via NASA.

Bottom line: Pyxis the Compass is a constellation lying in southern skies. But Northern Hemisphere viewers can get a glimpse of in March. Nicolas-Louis de Lacaille created the constellation in the 1700s.

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Pyxis the Compass is considered a constellation of the Southern Hemisphere skies. But northerners at southerly latitudes can see it, too, on March evenings.

Science news, night sky events and beautiful photos, all in one place. Click here to subscribe to our free daily newsletter.

The constellation Pyxis the Compass

March is a good month to view the constellation Pyxis the Compass. That’s assuming you’re far enough south on Earth’s globe. Pyxis is one of the 14 constellations that the French astronomer Nicolas-Louis de Lacaille created in the 1700s. It represents a ship’s compass. Conveniently, this ship’s compass lies on our sky’s dome next to the three constellations, Puppis, Vela and Carina, elements that made up the former constellation of Argo Navis. That was the great starry Ship that once sailed the southern skies.

By the way, don’t confuse Pyxis the Compass with Circinus. That’s a different constellation that represents a drawing compass.

Pyxis lies southeast of Canis Major the Greater Dog, with its very bright star Sirius. From Sirius, look toward the east to the quiet part of the sky where Pyxis resides. See the photo below.

View at EarthSky Community Photos. | Prateek Pandey in Bhopal, India (23 degrees north latitude) captured this photo of Pyxis, Canis Major and Puppis. Pyxis is best viewed from the Southern Hemisphere. But it can be seen from southerly latitudes in the Northern Hemisphere, too. Thank you, Prateek!

The stars of Pyxis

The Alpha and Beta stars of Pyxis lie in the southern part of the constellation. More specifically, Alpha Pyxidis is magnitude 3.68 and lies 845 light-years away. Likewise, just over 2 degrees to the south is Beta Pyxidis at magnitude 3.97 and lying 388 light-years away.

In addition, both Alpha and Beta have faint star clusters lying a half degree to the northwest. Alpha’s star cluster is NGC 2658 at magnitude 9.2. And Beta’s star cluster is NGC 2635 at magnitude 11.2. So with this in mind, you’ll want binoculars or a telescope to track them down. In particular, NGC 2635 is a real challenge.

However, there are two other deep-sky targets in Pyxis that are somewhat brighter. First, there’s NGC 2627. It’s a magnitude 8.4 star cluster lying 3 1/2 degrees northwest of Alpha, or just 1/2 degree southwest of Zeta Pyxidis, a magnitude 4.86 star. Then, the second one lies in the southeast corner of the constellation. It’s NGC 2818, a planetary nebula shining at magnitude 11.6. Which we can see in the glorious Hubble photo, below.

The stars of Pyxis are difficult to see from a location with light pollution. For instance, Pyxis the Compass’s brightest star is a faint magnitude 3.68. Image via International Astronomical Union/ Wikimedia Commons (CC BY 3.0).

The Hubble Space Telescope took this shot of the planetary nebula NGC 2818 in Pyxis in 2009. Image via NASA.

Bottom line: Pyxis the Compass is a constellation lying in southern skies. But Northern Hemisphere viewers can get a glimpse of in March. Nicolas-Louis de Lacaille created the constellation in the 1700s.

The post Pyxis the Compass shines in the March night sky first appeared on EarthSky.

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Are day and night equal on the equinox? Not exactly

EarthSky’s Raúl Cortés caught the March equinox sun at sunrise. Thanks, Raúl! See more of Raúl’s photos here. Are day and night equal? See below.

You deserve a daily dose of good news. For the latest in science and the night sky, click here to subscribe to our free daily newsletter.

More day than night

The March equinox will come on March 20, 2026, at 14:46 UTC (9:46 a.m. CDT). It’s the Northern Hemisphere’s autumn equinox and Southern Hemisphere’s spring equinox. You sometimes hear it said that, at the equinoxes, everyone receives equal daylight and darkness. But there’s really more daylight than darkness at the equinox, eight more minutes or so at mid-temperate latitudes. Two factors explain why we have more than 12 hours of daylight on this day of supposedly equal day and night. They are:

• The sun is a disk, not a point.
• Atmospheric refraction.

Read more about the March 2026 equinox: All you need to know

Illustrations like this one make it seem as if day and night should be equal at the equinox. In fact, they aren’t exactly equal. Image via Wikimedia Commons (CC BY-SA 2.0).

The sun is a disk, not a point

Watch any sunset, and you know the sun appears in Earth’s sky as a disk.

It’s not point-like, as stars are. And yet – by definition – most almanacs regard sunrise as when the leading edge of the sun first touches the eastern horizon. They define sunset as when the sun’s trailing edge finally touches the western horizon.

This provides an extra 2 1/2 to 3 minutes of daylight at mid-temperate latitudes.

Atmospheric refraction raises the sun about 1/2 degree upward in our sky at both sunrise and sunset. This advances the time of actual sunrise, while delaying the time of actual sunset. The result is several minutes of extra daylight, not just at an equinox, but every day. Image via Wikipedia (CC BY-SA 3.0).

Atmospheric refraction

The Earth’s atmosphere acts like a lens or prism. It uplifts the sun about 0.5 degrees from its true geometrical position whenever the sun nears the horizon. Coincidentally, the sun’s angular diameter spans about 0.5 degrees, as well.

In other words, when you see the sun on the horizon, it’s actually just below the horizon geometrically.

What does atmospheric refraction mean for the length of daylight? It advances the sunrise and delays the sunset, adding nearly another six minutes of daylight at mid-temperate latitudes. Hence, more daylight than night at the equinox.

Astronomical almanacs usually don’t give sunrise or sunset times to the second. That’s because atmospheric refraction varies somewhat, depending on air temperature, humidity and barometric pressure. Lower temperature, higher humidity and higher barometric pressure all increase atmospheric refraction.

On the day of the equinox, the center of the sun would set about 12 hours after rising. That’s given a level horizon, as at sea, and no atmospheric refraction.

Satellite views of Earth on the solstices and equinoxes. We are near the March equinox now. Images via NASA Earth Observatory.

Are day and night equal?

So, no, day and night are not exactly equal at the equinox.

And here’s a new word for you, equilux. The word is used to describe the day on which day and night are equal. The equilux happens a few to several days after the autumn equinox, and a few to several days before the spring equinox.

Much as earliest sunrises and latest sunsets vary with latitude, so the exact date of an equilux varies with latitude. That’s in contrast to the equinox itself, which is a whole-Earth event, happening at the same instant worldwide. At and near the equator, there is no equilux whatsoever. That’s because the daylight period is over 12 hours long every day of the year.

Visit timeanddate.com for the approximate date of equal day and night at your latitude

Bottom line: There’s slightly more day than night on the day of an equinox. That’s because the sun is a disk, not a point of light, and because Earth’s atmosphere refracts (bends) sunlight.

The post Are day and night equal on the equinox? Not exactly first appeared on EarthSky.

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EarthSky’s Raúl Cortés caught the March equinox sun at sunrise. Thanks, Raúl! See more of Raúl’s photos here. Are day and night equal? See below.

You deserve a daily dose of good news. For the latest in science and the night sky, click here to subscribe to our free daily newsletter.

More day than night

The March equinox will come on March 20, 2026, at 14:46 UTC (9:46 a.m. CDT). It’s the Northern Hemisphere’s autumn equinox and Southern Hemisphere’s spring equinox. You sometimes hear it said that, at the equinoxes, everyone receives equal daylight and darkness. But there’s really more daylight than darkness at the equinox, eight more minutes or so at mid-temperate latitudes. Two factors explain why we have more than 12 hours of daylight on this day of supposedly equal day and night. They are:

• The sun is a disk, not a point.
• Atmospheric refraction.

Read more about the March 2026 equinox: All you need to know

Illustrations like this one make it seem as if day and night should be equal at the equinox. In fact, they aren’t exactly equal. Image via Wikimedia Commons (CC BY-SA 2.0).

The sun is a disk, not a point

Watch any sunset, and you know the sun appears in Earth’s sky as a disk.

It’s not point-like, as stars are. And yet – by definition – most almanacs regard sunrise as when the leading edge of the sun first touches the eastern horizon. They define sunset as when the sun’s trailing edge finally touches the western horizon.

This provides an extra 2 1/2 to 3 minutes of daylight at mid-temperate latitudes.

Atmospheric refraction raises the sun about 1/2 degree upward in our sky at both sunrise and sunset. This advances the time of actual sunrise, while delaying the time of actual sunset. The result is several minutes of extra daylight, not just at an equinox, but every day. Image via Wikipedia (CC BY-SA 3.0).

Atmospheric refraction

The Earth’s atmosphere acts like a lens or prism. It uplifts the sun about 0.5 degrees from its true geometrical position whenever the sun nears the horizon. Coincidentally, the sun’s angular diameter spans about 0.5 degrees, as well.

In other words, when you see the sun on the horizon, it’s actually just below the horizon geometrically.

What does atmospheric refraction mean for the length of daylight? It advances the sunrise and delays the sunset, adding nearly another six minutes of daylight at mid-temperate latitudes. Hence, more daylight than night at the equinox.

Astronomical almanacs usually don’t give sunrise or sunset times to the second. That’s because atmospheric refraction varies somewhat, depending on air temperature, humidity and barometric pressure. Lower temperature, higher humidity and higher barometric pressure all increase atmospheric refraction.

On the day of the equinox, the center of the sun would set about 12 hours after rising. That’s given a level horizon, as at sea, and no atmospheric refraction.

Satellite views of Earth on the solstices and equinoxes. We are near the March equinox now. Images via NASA Earth Observatory.

Are day and night equal?

So, no, day and night are not exactly equal at the equinox.

And here’s a new word for you, equilux. The word is used to describe the day on which day and night are equal. The equilux happens a few to several days after the autumn equinox, and a few to several days before the spring equinox.

Much as earliest sunrises and latest sunsets vary with latitude, so the exact date of an equilux varies with latitude. That’s in contrast to the equinox itself, which is a whole-Earth event, happening at the same instant worldwide. At and near the equator, there is no equilux whatsoever. That’s because the daylight period is over 12 hours long every day of the year.

Visit timeanddate.com for the approximate date of equal day and night at your latitude

Bottom line: There’s slightly more day than night on the day of an equinox. That’s because the sun is a disk, not a point of light, and because Earth’s atmosphere refracts (bends) sunlight.

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