Moon phase a clue to the sun’s position

Above: Draw a straight line from one horn of a crescent moon to the other. Then from the middle of that line, between the horns, draw another straight line perpendicular to the first. The illuminated part of the crescent points to the sun. You can extend the line down to the point on the horizon roughly where the sun went down.

In late December 2019 – if you look in a clear western sky after sunset – you’ll easily spot the very bright planet Venus, along with a waxing crescent moon. There might be earthshine illuminating the moon’s darkened portion. You know, of course, that the moon changes its phase. But did you know you can tell where the sun is – even when the sun is below the horizon – just by observing the moon phase? It’s especially easy with a crescent moon up to first quarter phase.

And, once you learn to use the moon in this way, you’ll gain a lot understanding about what causes the moon to change its phase in the first place. Plus just thinking about it, each time you see a crescent moon, will add to your perception of yourself as a person standing on a world in space.

So here’s what you do. When you see a crescent moon, notice that it has two ends or “horns.”

Imagine that you draw a straight line from one horn to the other. Then from the middle of that line, between the horns, imagine another straight line perpendicular to the first (that is, at a “right” angle). Imagine that line drawn down through the illuminated part of the crescent. That line points to the sun. You can extend the line down to the point on the horizon roughly where the sun went down.

Draw a straight line from one horn to the other. Then from the middle of that line, between the horns, imagine another straight line perpendicular to the first (that is, at a “right” angle). The illuminated part of the crescent points to the sun. You can extend the line down to the point on the horizon roughly where the sun went down.

By the time the moon waxes to the first quarter phase, of course, the first line above is just the “flat” edge of the moon. After that phase, it becomes a bit harder to use the moon to find the sun’s position, when the sun is below the horizon, but experienced stargazers can and do still do it.

Why does this work? Well, it’s the sun that causes the moon’s phases. The moon is a globe in space, just as Earth is a globe. And like the Earth, the moon has a day side and a night side. The varying moon phases we see are just varying fractions of the moon’s day side. Want more about this? Try our article 4 keys to understanding moon phases.

About the moon on New Year’s Eve 2019 … it’s near the dazzlingly bright planet Venus and exceedingly faint planet Neptune.

On the evening of December 31, 2019, you’ll find the moon in about this position with respect to the very bright planet Venus. The planet Neptune is near the moon in our sky on this date, but Neptune cannot be seen with the eye alone.

You’ll notice Venus right away, but you won’t see Neptune with the unaided eye. You’ll need at least binoculars to see this distant planet. Click here for a detailed sky chart showing Neptune’s location in 2019 and 2020.

Bottom line: The moon phase can point you to the sun’s location in the sky, even when the sun is below the horizon.

Read more: EarthSky’s guide to the bright planets

Easily locate stars and constellations during any day and time with EarthSky’s Planisphere.

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Above: Draw a straight line from one horn of a crescent moon to the other. Then from the middle of that line, between the horns, draw another straight line perpendicular to the first. The illuminated part of the crescent points to the sun. You can extend the line down to the point on the horizon roughly where the sun went down.

In late December 2019 – if you look in a clear western sky after sunset – you’ll easily spot the very bright planet Venus, along with a waxing crescent moon. There might be earthshine illuminating the moon’s darkened portion. You know, of course, that the moon changes its phase. But did you know you can tell where the sun is – even when the sun is below the horizon – just by observing the moon phase? It’s especially easy with a crescent moon up to first quarter phase.

And, once you learn to use the moon in this way, you’ll gain a lot understanding about what causes the moon to change its phase in the first place. Plus just thinking about it, each time you see a crescent moon, will add to your perception of yourself as a person standing on a world in space.

So here’s what you do. When you see a crescent moon, notice that it has two ends or “horns.”

Imagine that you draw a straight line from one horn to the other. Then from the middle of that line, between the horns, imagine another straight line perpendicular to the first (that is, at a “right” angle). Imagine that line drawn down through the illuminated part of the crescent. That line points to the sun. You can extend the line down to the point on the horizon roughly where the sun went down.

Draw a straight line from one horn to the other. Then from the middle of that line, between the horns, imagine another straight line perpendicular to the first (that is, at a “right” angle). The illuminated part of the crescent points to the sun. You can extend the line down to the point on the horizon roughly where the sun went down.

By the time the moon waxes to the first quarter phase, of course, the first line above is just the “flat” edge of the moon. After that phase, it becomes a bit harder to use the moon to find the sun’s position, when the sun is below the horizon, but experienced stargazers can and do still do it.

Why does this work? Well, it’s the sun that causes the moon’s phases. The moon is a globe in space, just as Earth is a globe. And like the Earth, the moon has a day side and a night side. The varying moon phases we see are just varying fractions of the moon’s day side. Want more about this? Try our article 4 keys to understanding moon phases.

About the moon on New Year’s Eve 2019 … it’s near the dazzlingly bright planet Venus and exceedingly faint planet Neptune.

On the evening of December 31, 2019, you’ll find the moon in about this position with respect to the very bright planet Venus. The planet Neptune is near the moon in our sky on this date, but Neptune cannot be seen with the eye alone.

You’ll notice Venus right away, but you won’t see Neptune with the unaided eye. You’ll need at least binoculars to see this distant planet. Click here for a detailed sky chart showing Neptune’s location in 2019 and 2020.

Bottom line: The moon phase can point you to the sun’s location in the sky, even when the sun is below the horizon.

Read more: EarthSky’s guide to the bright planets

Easily locate stars and constellations during any day and time with EarthSky’s Planisphere.

from EarthSky https://ift.tt/2ZD92HQ

Can you see stars’ different colors?

Tonight … notice that the stars are like wildflowers, in that each star radiates with a different color of the rainbow. Have you ever noticed their various hues? Let’s explore some of the stars that you’ll see in the meadow of night tonight.

In the northeastern sky at evening shines a bright star called Capella, the Little She Goat, in the constellation Auriga. Like brighter Sirius, which rises around 8 to 9 p.m. in the southeast, Capella often flickers madly when low in the sky. This effect has nothing to do with the stars themselves but rather is caused by Earth’s turbulent atmosphere.

The effect is particularly prominent with the stars Capella and Sirius because they are so bright.

Can you spot Capella? If so, notice that it’s a golden star. A star’s spectral type indicates its color. Capella is a G star, and, in that classification, it’s like our sun. Both our sun and Capella shine with a golden light.

Sirius, by the way – the sky’s brightest star, after the sun – is almost always described as a white star.

EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store

The constellation Auriga in the northeast sky at nightfall in December. The brightest star in this constellation is golden Capella. The bright red star just above the horizon is Aldebaran in the constellation Taurus. Image via AlltheSky.com

The stars’ true colors are apparent when they climb higher in the sky and above the turbulence of Earth’s atmosphere. If you have good eyesight and a dark, clear sky, you should be able to detect hints of color with the brighter stars. If you have difficulty discerning star colors with the unaided eye, try looking at these stars with binoculars.

Also contrast golden Capella with the reddish star Aldebaran and the stars of the misty Pleiades cluster higher up.

The light of a star reveals many things, but most directly the stars’ surface temperatures. The yellowish color of Capella indicates a mid-range surface temperature, much like our sun. The red of Aldebaran is typical of the lower surface temperature of an older star, whereas the blue of the Pleiades reveals their high surface temperature and young age.

The blue-white star Elnath, by the way, is officially part of Taurus, but it typically is considered part of Auriga as well.

There is a whole spectrum of stellar color sparkling in the sky tonight, from cool red stars to hot blue-white ones, and middle range yellow stars!

The H-R diagram, showing the colors of stars. Image via Wikipedia

Bottom line: Winter is the perfect season for noticing the colors of the stars. Never noticed them? Our sky chart can help guide your eye.

Never miss another full moon. Order your 2018 EarthSky lunar calendar today!

Donate: Your support means the world to us

from EarthSky https://ift.tt/2RvQLHj

Tonight … notice that the stars are like wildflowers, in that each star radiates with a different color of the rainbow. Have you ever noticed their various hues? Let’s explore some of the stars that you’ll see in the meadow of night tonight.

In the northeastern sky at evening shines a bright star called Capella, the Little She Goat, in the constellation Auriga. Like brighter Sirius, which rises around 8 to 9 p.m. in the southeast, Capella often flickers madly when low in the sky. This effect has nothing to do with the stars themselves but rather is caused by Earth’s turbulent atmosphere.

The effect is particularly prominent with the stars Capella and Sirius because they are so bright.

Can you spot Capella? If so, notice that it’s a golden star. A star’s spectral type indicates its color. Capella is a G star, and, in that classification, it’s like our sun. Both our sun and Capella shine with a golden light.

Sirius, by the way – the sky’s brightest star, after the sun – is almost always described as a white star.

EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store

The constellation Auriga in the northeast sky at nightfall in December. The brightest star in this constellation is golden Capella. The bright red star just above the horizon is Aldebaran in the constellation Taurus. Image via AlltheSky.com

The stars’ true colors are apparent when they climb higher in the sky and above the turbulence of Earth’s atmosphere. If you have good eyesight and a dark, clear sky, you should be able to detect hints of color with the brighter stars. If you have difficulty discerning star colors with the unaided eye, try looking at these stars with binoculars.

Also contrast golden Capella with the reddish star Aldebaran and the stars of the misty Pleiades cluster higher up.

The light of a star reveals many things, but most directly the stars’ surface temperatures. The yellowish color of Capella indicates a mid-range surface temperature, much like our sun. The red of Aldebaran is typical of the lower surface temperature of an older star, whereas the blue of the Pleiades reveals their high surface temperature and young age.

The blue-white star Elnath, by the way, is officially part of Taurus, but it typically is considered part of Auriga as well.

There is a whole spectrum of stellar color sparkling in the sky tonight, from cool red stars to hot blue-white ones, and middle range yellow stars!

The H-R diagram, showing the colors of stars. Image via Wikipedia

Bottom line: Winter is the perfect season for noticing the colors of the stars. Never noticed them? Our sky chart can help guide your eye.

Never miss another full moon. Order your 2018 EarthSky lunar calendar today!

Donate: Your support means the world to us

from EarthSky https://ift.tt/2RvQLHj

Top 9 EarthSky stories of 2019

Who could forget this image? It’s the first direct image of a black hole, in the galaxy M87, released in April 2019. This long-sought image provided the strongest evidence to date for the existence of supermassive black holes and opened a new window onto the study of black holes, their event horizons, and gravity. Image via Event Horizon Telescope Collaboration.

1. January 3, 2019: China’s Chang’e 4 spacecraft landed on the moon’s far side. The year started with a bang (or was it a bump?) when a Chinese spacecraft called Chang’e 4 became the first-ever mission to land on the side of the moon that faces continually away from Earth. We’re linking here not just to the announcement of the landing, but to a story published a few months later on what early results from Chang’e 4 revealed about this mysterious part of the moon.
2. Mid-January, 2019: A 2nd repeating radio burst from the depths of space. Astronomers announced that, of the more than 60 Fast Radio Bursts found so far, only one has ever been seen to repeat from the same source … until now.
3. February 22, 2019: Japan’s Hayabusa2 successfully lands on asteroid Ryugu. The Hayabusa2 spacecraft touched down briefly and successfully on asteroid Ryugu, 200 million miles (300 million km) from Earth. It successfully fired a bullet into the asteroid to puff up dust for sample collection.
4. March 24, 2019: Scientists gathered to contemplate the Great Silence. In other words … if advanced alien civilizations are out there, why haven’t we heard from them? Scientists call this Fermi’s Paradox – aka The Great Silence – and they gathered in Paris to discuss it.
5. April 7, 2019: Scientists closed in on mysterious Mars methane. For the first time, an in-situ measurement of methane on Mars – made by NASA’s Curiosity rover – was independently confirmed from orbit, by ESA’s Mars Express. Could it be a clue to Mars life?
6. April 10, 2019: Astronomers released the first real black hole image. Researchers unveiled a history-making image – the first ever – of the shadow of a supermassive black hole.
7. September 7, 2019: Contact with India moon lander lost, moments before touchdown. The Vikram lander was to have made India the 4th nation of Earth to soft land on the moon. It was heartbreaking when contact with the craft was lost just 1.3 miles (2.1 km) above the moon’s surface.
8. August 30, 2019: Astronomers spied a 2nd interstellar visitor. Astronomers realized the object they initially labeled C/2019 Q4 – later officially identified as a comet and re-labeled 2I/Borisov – came from a place far, far away. It’s only the 2nd interstellar object ever detected, after ‘Oumuamua in 2017. The link goes to an update on this object, in November 2019, after the first peer-reviewed paper about it.
9. October 31, 2019: A small asteroid paid a heavy price for nearly striking Earth: Earth’s gravity bent the trajectory of asteroid C0PPEV1 – also known as 2019 UN13 – as it swept only 3,852 miles (6,200 km) above Africa.

Bottom line: Top EarthSky news stories of 2019.

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Who could forget this image? It’s the first direct image of a black hole, in the galaxy M87, released in April 2019. This long-sought image provided the strongest evidence to date for the existence of supermassive black holes and opened a new window onto the study of black holes, their event horizons, and gravity. Image via Event Horizon Telescope Collaboration.

1. January 3, 2019: China’s Chang’e 4 spacecraft landed on the moon’s far side. The year started with a bang (or was it a bump?) when a Chinese spacecraft called Chang’e 4 became the first-ever mission to land on the side of the moon that faces continually away from Earth. We’re linking here not just to the announcement of the landing, but to a story published a few months later on what early results from Chang’e 4 revealed about this mysterious part of the moon.
2. Mid-January, 2019: A 2nd repeating radio burst from the depths of space. Astronomers announced that, of the more than 60 Fast Radio Bursts found so far, only one has ever been seen to repeat from the same source … until now.
3. February 22, 2019: Japan’s Hayabusa2 successfully lands on asteroid Ryugu. The Hayabusa2 spacecraft touched down briefly and successfully on asteroid Ryugu, 200 million miles (300 million km) from Earth. It successfully fired a bullet into the asteroid to puff up dust for sample collection.
4. March 24, 2019: Scientists gathered to contemplate the Great Silence. In other words … if advanced alien civilizations are out there, why haven’t we heard from them? Scientists call this Fermi’s Paradox – aka The Great Silence – and they gathered in Paris to discuss it.
5. April 7, 2019: Scientists closed in on mysterious Mars methane. For the first time, an in-situ measurement of methane on Mars – made by NASA’s Curiosity rover – was independently confirmed from orbit, by ESA’s Mars Express. Could it be a clue to Mars life?
6. April 10, 2019: Astronomers released the first real black hole image. Researchers unveiled a history-making image – the first ever – of the shadow of a supermassive black hole.
7. September 7, 2019: Contact with India moon lander lost, moments before touchdown. The Vikram lander was to have made India the 4th nation of Earth to soft land on the moon. It was heartbreaking when contact with the craft was lost just 1.3 miles (2.1 km) above the moon’s surface.
8. August 30, 2019: Astronomers spied a 2nd interstellar visitor. Astronomers realized the object they initially labeled C/2019 Q4 – later officially identified as a comet and re-labeled 2I/Borisov – came from a place far, far away. It’s only the 2nd interstellar object ever detected, after ‘Oumuamua in 2017. The link goes to an update on this object, in November 2019, after the first peer-reviewed paper about it.
9. October 31, 2019: A small asteroid paid a heavy price for nearly striking Earth: Earth’s gravity bent the trajectory of asteroid C0PPEV1 – also known as 2019 UN13 – as it swept only 3,852 miles (6,200 km) above Africa.

Bottom line: Top EarthSky news stories of 2019.

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Top 9 EarthSky images of 2019

Thanks to all who posted this year at EarthSky Community Photos. If you have a great recent photo of the Earth or sky, submit it here.

View larger at EarthSky Community Photos. | As 2019 began, the eastern sky before sunup featured 3 bright planets, Venus, Jupiter qnd Saturn. In late January and early February, the moon swept through. Karl Diefenderfer in Quakertown, Pennsylvania, caught the waning moon, with bright Venus above right, on February 1, 2019. He wrote: “Chilly start to the day at -4F.” Thank you, Karl. View more morning planet photos from early 2019.

View larger at EarthSky Community Photo. | Mike Mezeul II captured what’s called “firefall” at Yosemite National Park on February 17, 2019. He wrote: “For two weeks out of the year, a spectacular event known as the firefall takes place within Yosemite National Park. Hundreds if not thousands of photographers flock to the valley in hopes of capturing the elusive moment, that is, if the weather, snow and light cooperate. If Yosemite receives an ample amount of snowfall throughout the winter, and if the western horizon stays clear, the last few minutes of daylight fall perfectly upon Horsetail Falls and illuminate it in a vibrant orange and red. The waterfall glows so fiercely that it appears to be on fire. Yesterday, after the valley received several feet of snow for a few days, one last clearing snowstorm led to the perfect mix of ingredients. Water flowing from the beautiful Horsetail Falls and a dazzling mix of broken clouds floating past El Capitan as the sunset set the fall ablaze.” Thank you, Mike!

Jingyi Zhang and Wang Zheng captured this stunning dragon shape in an aurora over Iceland in early February 2019. The image ran as the Astronomy Picture of the Day for February 18, 2019, which wrote: “This iconic display was so enthralling that the photographer’s mother ran out to see it and was captured in the foreground.” View more aurora photos from that same awesome night.

View at EarthSky Community Photos. | It has been a quiet year for sunspots. We’re near the lowest ebb of the 11-year sunspot cycle. But, in April 2019, a magnificent solitary sunspot – AR2738 – made its way across the sun’s face over a period of a couple of weeks. Padraic Koen in Adelaide, Australia, caught this closeup of sunspot AR2738 on April 14, 2019. Thank you, Padraic. View more photos of AR2738.

View at EarthSky Community Photos. | The month of June always brings new sightings of noctilucent clouds – also called night-shining clouds – at northerly latitudes. These clouds are a seasonal phenomenon. Hans Van Boven wrote, “Beautiful noctilucent clouds were observed above the Netherlands in the night from 12 to 13 June 2019.” Thank you, Hans! View more photos of noctilucent clouds in 2019, along with an explanation of what makes these clouds.

View at EarthSky Community Photos. | Fred Walder captured this rainbow and waterfall on June 17, 2019, in California’s Yosemite National Park. The streaks in the sky above – captured in a long-exposure photo – are called star trails. View more star trails photos.

View larger. | July 2, 2019 brought a total eclipse of the sun. Here’s the scene on a beach during totality in La Serena, Chile – darkness during the daytime at mid-eclipse – as captured by our friend Eliot Herman. Thank you, Eliot! View more eclipse photos by Eliot, and still more eclipse photos, by other EarthSky community members. Thanks to all!

August, of course, is the month of the Perseid meteor shower. Astrophotographer Ruslan Merzlyakov wrote: “Proud to present the biggest project I have ever made! Perseid meteor shower 2019 over Scandinavia’s first dark sky park, the island of Møn [in Denmark]. Five nights. Two cameras. Fifteen hours of observation. Some 3000+ images. Over 70 GB of data.” Thank you, Ruslan!

View at EarthSky Community Photos. | Claire Shickora was at Blythe Island Regional Park, Brunswick, Georgia, on Thanksgiving evening – November 28, 2019 – when she caught this beautiful image. She wrote: “After a spectacular sunset at the marina, the clouds broke up enough for me to get this shot (from right to left) of Jupiter, Venus, the moon, and barely-visible Saturn. Passersby were awed as I pointed out exactly what I was photographing.” Thank you, Claire! View more photos of the moon and planets in the evening sky, around Thanksgiving.

Bottom line: Nine favorite EarthSky images in 2019. Of course … they’re all our favorites. Thanks to all who submitted photos in 2019! Visit EarthSky Community Photos, or submit your photo here.

from EarthSky https://ift.tt/2F1FVnR

Thanks to all who posted this year at EarthSky Community Photos. If you have a great recent photo of the Earth or sky, submit it here.

View larger at EarthSky Community Photos. | As 2019 began, the eastern sky before sunup featured 3 bright planets, Venus, Jupiter qnd Saturn. In late January and early February, the moon swept through. Karl Diefenderfer in Quakertown, Pennsylvania, caught the waning moon, with bright Venus above right, on February 1, 2019. He wrote: “Chilly start to the day at -4F.” Thank you, Karl. View more morning planet photos from early 2019.

View larger at EarthSky Community Photo. | Mike Mezeul II captured what’s called “firefall” at Yosemite National Park on February 17, 2019. He wrote: “For two weeks out of the year, a spectacular event known as the firefall takes place within Yosemite National Park. Hundreds if not thousands of photographers flock to the valley in hopes of capturing the elusive moment, that is, if the weather, snow and light cooperate. If Yosemite receives an ample amount of snowfall throughout the winter, and if the western horizon stays clear, the last few minutes of daylight fall perfectly upon Horsetail Falls and illuminate it in a vibrant orange and red. The waterfall glows so fiercely that it appears to be on fire. Yesterday, after the valley received several feet of snow for a few days, one last clearing snowstorm led to the perfect mix of ingredients. Water flowing from the beautiful Horsetail Falls and a dazzling mix of broken clouds floating past El Capitan as the sunset set the fall ablaze.” Thank you, Mike!

Jingyi Zhang and Wang Zheng captured this stunning dragon shape in an aurora over Iceland in early February 2019. The image ran as the Astronomy Picture of the Day for February 18, 2019, which wrote: “This iconic display was so enthralling that the photographer’s mother ran out to see it and was captured in the foreground.” View more aurora photos from that same awesome night.

View at EarthSky Community Photos. | It has been a quiet year for sunspots. We’re near the lowest ebb of the 11-year sunspot cycle. But, in April 2019, a magnificent solitary sunspot – AR2738 – made its way across the sun’s face over a period of a couple of weeks. Padraic Koen in Adelaide, Australia, caught this closeup of sunspot AR2738 on April 14, 2019. Thank you, Padraic. View more photos of AR2738.

View at EarthSky Community Photos. | The month of June always brings new sightings of noctilucent clouds – also called night-shining clouds – at northerly latitudes. These clouds are a seasonal phenomenon. Hans Van Boven wrote, “Beautiful noctilucent clouds were observed above the Netherlands in the night from 12 to 13 June 2019.” Thank you, Hans! View more photos of noctilucent clouds in 2019, along with an explanation of what makes these clouds.

View at EarthSky Community Photos. | Fred Walder captured this rainbow and waterfall on June 17, 2019, in California’s Yosemite National Park. The streaks in the sky above – captured in a long-exposure photo – are called star trails. View more star trails photos.

View larger. | July 2, 2019 brought a total eclipse of the sun. Here’s the scene on a beach during totality in La Serena, Chile – darkness during the daytime at mid-eclipse – as captured by our friend Eliot Herman. Thank you, Eliot! View more eclipse photos by Eliot, and still more eclipse photos, by other EarthSky community members. Thanks to all!

August, of course, is the month of the Perseid meteor shower. Astrophotographer Ruslan Merzlyakov wrote: “Proud to present the biggest project I have ever made! Perseid meteor shower 2019 over Scandinavia’s first dark sky park, the island of Møn [in Denmark]. Five nights. Two cameras. Fifteen hours of observation. Some 3000+ images. Over 70 GB of data.” Thank you, Ruslan!

View at EarthSky Community Photos. | Claire Shickora was at Blythe Island Regional Park, Brunswick, Georgia, on Thanksgiving evening – November 28, 2019 – when she caught this beautiful image. She wrote: “After a spectacular sunset at the marina, the clouds broke up enough for me to get this shot (from right to left) of Jupiter, Venus, the moon, and barely-visible Saturn. Passersby were awed as I pointed out exactly what I was photographing.” Thank you, Claire! View more photos of the moon and planets in the evening sky, around Thanksgiving.

Bottom line: Nine favorite EarthSky images in 2019. Of course … they’re all our favorites. Thanks to all who submitted photos in 2019! Visit EarthSky Community Photos, or submit your photo here.

from EarthSky https://ift.tt/2F1FVnR

Look for the Northern Cross

Tonight, look for the Northern Cross. It isn’t as famous as its counterpart – the Southern Cross – visible from the Southern Hemisphere or the northern tropics. But the Northern Cross also looks like a cross, and it’s pretty easy to spot. It’s a large, noticeable star pattern.

The star Deneb marks the top of the Northern Cross, and the star Albireo marks the bottom. Tonight – or any night in late December – you can find the Northern Cross shining fairly high in the west at nightfall, as seen from mid-northern latitudes. It sinks downward during the evening hours, and stands proudly over the west-northwest horizon around mid-evening.

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Here’s another look at the famous Northern Cross. It’s part of the constellation Cygnus the Swan. Photo via Flickr user Janne.

The Northern Cross is what’s known as an asterism. In other words, it’s not a constellation but simply a noticeable pattern of stars. It’s part of the constellation Cygnus the Swan.

As an added bonus, if you have a pair of binoculars, break them out this evening and point them toward the Northern Cross and its larger constellation Cygnus the Swan. In this direction, you’ll find a part of our Milky Way galaxy that is called the Cygnus Star Cloud. It is part of the spiral arm of our galaxy that also contains our sun, and you should be able to pick out stars from it if the night is clear in your area.

By the way, we get many questions from people in northern latitudes about if and when they can view the Southern Cross in their portion of the sky. The truth is that unless you live close to the tropics (Hawaii, or the southernmost parts of Texas or Florida for those of us in the U.S.), you won’t be able to view the Southern Cross, also known as the constellation Crux. It won’t rise above your horizon. To find out how to locate Crux in Hawaii at this time of year, look here.

Bottom line: Learn to recognize a famous star pattern known as the Northern Cross, which stands upright over the west-northwest horizon in December.

Looking for a sky almanac? EarthSky recommends …

EarthSky lunar calendars make great gifts for astronomy-minded friends and family. Going fast!

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Tonight, look for the Northern Cross. It isn’t as famous as its counterpart – the Southern Cross – visible from the Southern Hemisphere or the northern tropics. But the Northern Cross also looks like a cross, and it’s pretty easy to spot. It’s a large, noticeable star pattern.

The star Deneb marks the top of the Northern Cross, and the star Albireo marks the bottom. Tonight – or any night in late December – you can find the Northern Cross shining fairly high in the west at nightfall, as seen from mid-northern latitudes. It sinks downward during the evening hours, and stands proudly over the west-northwest horizon around mid-evening.

Donate: Your support means the world to us

Here’s another look at the famous Northern Cross. It’s part of the constellation Cygnus the Swan. Photo via Flickr user Janne.

The Northern Cross is what’s known as an asterism. In other words, it’s not a constellation but simply a noticeable pattern of stars. It’s part of the constellation Cygnus the Swan.

As an added bonus, if you have a pair of binoculars, break them out this evening and point them toward the Northern Cross and its larger constellation Cygnus the Swan. In this direction, you’ll find a part of our Milky Way galaxy that is called the Cygnus Star Cloud. It is part of the spiral arm of our galaxy that also contains our sun, and you should be able to pick out stars from it if the night is clear in your area.

By the way, we get many questions from people in northern latitudes about if and when they can view the Southern Cross in their portion of the sky. The truth is that unless you live close to the tropics (Hawaii, or the southernmost parts of Texas or Florida for those of us in the U.S.), you won’t be able to view the Southern Cross, also known as the constellation Crux. It won’t rise above your horizon. To find out how to locate Crux in Hawaii at this time of year, look here.

Bottom line: Learn to recognize a famous star pattern known as the Northern Cross, which stands upright over the west-northwest horizon in December.

Looking for a sky almanac? EarthSky recommends …

EarthSky lunar calendars make great gifts for astronomy-minded friends and family. Going fast!

from EarthSky https://ift.tt/2Q5fVy9

Don’t miss the young moon and Venus

As the year wanes, the young moon returns to the west after sunset.

From virtually everyplace worldwide on December 27, the moon will be better than one day (24 hours) old as the sun sets. If your sky is clear, you can catch the whisker-thin waxing crescent (and possibly, with much more difficulty, the planet Saturn) at dusk. You’ll surely see dazzling Venus, above them, blazing in Friday evening’s western twilight sky. This young moon will be fresh from its ring of fire eclipse a day earlier.

The Western Hemisphere will have the easiest view of the young moon after sunset on December 27. From the Eastern Hemisphere on December 27, the moon will be more challenging, but lots of fun. More about viewing from the Eastern Hemisphere below.

On the following evenings – December 28 and 29 – the moon will be much easier for all. It’ll be closest to Venus Saturday evening, December 28. A wondrous sky scene for the whole world! #OneEarth #OneSky

The bright couple – two brightest lights in our sky after the sun – will be beautiful again on Sunday evening, December 29.

By the way, although we show the planet Saturn on our sky chart above, it’ll take a deliberate effort (and possibly binoculars) to spot this world in the glare of evening twilight.

View larger. | Last year, April Singer caught the young moon after sunset on December 8, 2018, with Saturn to its upper left. This year, you’ll see Venus instead of Saturn to the upper left of the moon (from northerly latitudes). Northern New Mexico, U.S. Photo by April Singer Photography. Way to go, April!

Young moon from Eastern Hemisphere on December 27. We’re not counting out the world’s Eastern Hemisphere on December 27. If you live in that part of the world, you might also catch a young(er) and slender(er) crescent after sunset that evening. From virtually everyplace worldwide, the moon will be better than one day (24 hours) old as the sun sets on December 27. It’s usually quite difficult to see a moon that’s less than one day (24 hours) old. It’s easier – though still a challenge – to spot a thin moon that’s just over a day old.

That challenge will occur for the world’s Eastern Hemisphere on December 27, where the moon will be younger than for us in the West. Look sooner after sunset. Have a totally unobstructed horizon. Bring binoculars!

Day and night sides of Earth one day (24 hours) after new moon (December 27, 2019 at 5:13 UTC). The shadow line at the far right and far left depicts sunset. As the line of sunset moves westward (right to left) across the globe, the moon continually edges farther away from the glare of sunset. The moon will be about 1 1/2 days old at sunset in western Europe and Africa, and about 1 3/4 days old as the sun sets in the Americas. Image via EarthView.

No matter where you live worldwide, you’ll have a better chance of spotting the moon on December 28, because a wider crescent will stay out longer after sundown than on December 27. Additionally, the moon will be closer to Venus on December 28, offering a more stunning view of the evening couple.

To maximize your chances of spotting the beautiful evening crescent (and/or Saturn), find an unobstructed horizon in the direction of sunset. A lofty position – atop a mountain or balcony – would help out as well, enabling you to peek a little farther over the horizon. Binoculars come in handy, too, for teasing out the pale, skinny crescent (or Saturn) from the glare of evening twilight.

Want to know when the moon sets in your sky? The Sunrise and Sunset Calendar gives you the moonset time – but remember to check the Moonrise and moonset box.

Want to know the moon’s position relative to the bright planets and the constellations of the zodiac? Your wish is granted, courtesy of Heavens-Above.com!

When the moon shows itself as a slender waxing crescent in Earth’s sky, then our planet beams a nearly-full waning gibbous Earth in the moon’s sky. The almost-full Earth, like a mirror, reflects sunlight and lights up the moon’s dark side. The moon, in turn, reflects sunlight back to Earth. Hence, that soft luminescence giving definition to the nighttime side of the moon is earthshine – twice-reflected sunlight. Look for soft glow of earthshine, with either the unaided eye or binoculars, on the dark side of the moon over the next several days.

View larger at EarthSky Community Photos. Peter Lowenstein of Mutare, Zimbabwe, caught the old waning crescent moon (and the planet Mercury to the moon’s lower right) in the east before sunrise December 25, 2019. To catch the upcoming young moon, look westward after sunset on December 27, 2019. Good luck! Thank you Peter!

Bottom line: Think photo opportunity this weekend (December 27-29, 2019) as the brightest and 2nd-brightest sky objects – the moon and Venus – beautify the evening twilight shortly after sunset.

from EarthSky https://ift.tt/351ddOC

As the year wanes, the young moon returns to the west after sunset.

From virtually everyplace worldwide on December 27, the moon will be better than one day (24 hours) old as the sun sets. If your sky is clear, you can catch the whisker-thin waxing crescent (and possibly, with much more difficulty, the planet Saturn) at dusk. You’ll surely see dazzling Venus, above them, blazing in Friday evening’s western twilight sky. This young moon will be fresh from its ring of fire eclipse a day earlier.

The Western Hemisphere will have the easiest view of the young moon after sunset on December 27. From the Eastern Hemisphere on December 27, the moon will be more challenging, but lots of fun. More about viewing from the Eastern Hemisphere below.

On the following evenings – December 28 and 29 – the moon will be much easier for all. It’ll be closest to Venus Saturday evening, December 28. A wondrous sky scene for the whole world! #OneEarth #OneSky

The bright couple – two brightest lights in our sky after the sun – will be beautiful again on Sunday evening, December 29.

By the way, although we show the planet Saturn on our sky chart above, it’ll take a deliberate effort (and possibly binoculars) to spot this world in the glare of evening twilight.

View larger. | Last year, April Singer caught the young moon after sunset on December 8, 2018, with Saturn to its upper left. This year, you’ll see Venus instead of Saturn to the upper left of the moon (from northerly latitudes). Northern New Mexico, U.S. Photo by April Singer Photography. Way to go, April!

Young moon from Eastern Hemisphere on December 27. We’re not counting out the world’s Eastern Hemisphere on December 27. If you live in that part of the world, you might also catch a young(er) and slender(er) crescent after sunset that evening. From virtually everyplace worldwide, the moon will be better than one day (24 hours) old as the sun sets on December 27. It’s usually quite difficult to see a moon that’s less than one day (24 hours) old. It’s easier – though still a challenge – to spot a thin moon that’s just over a day old.

That challenge will occur for the world’s Eastern Hemisphere on December 27, where the moon will be younger than for us in the West. Look sooner after sunset. Have a totally unobstructed horizon. Bring binoculars!

Day and night sides of Earth one day (24 hours) after new moon (December 27, 2019 at 5:13 UTC). The shadow line at the far right and far left depicts sunset. As the line of sunset moves westward (right to left) across the globe, the moon continually edges farther away from the glare of sunset. The moon will be about 1 1/2 days old at sunset in western Europe and Africa, and about 1 3/4 days old as the sun sets in the Americas. Image via EarthView.

No matter where you live worldwide, you’ll have a better chance of spotting the moon on December 28, because a wider crescent will stay out longer after sundown than on December 27. Additionally, the moon will be closer to Venus on December 28, offering a more stunning view of the evening couple.

To maximize your chances of spotting the beautiful evening crescent (and/or Saturn), find an unobstructed horizon in the direction of sunset. A lofty position – atop a mountain or balcony – would help out as well, enabling you to peek a little farther over the horizon. Binoculars come in handy, too, for teasing out the pale, skinny crescent (or Saturn) from the glare of evening twilight.

Want to know when the moon sets in your sky? The Sunrise and Sunset Calendar gives you the moonset time – but remember to check the Moonrise and moonset box.

Want to know the moon’s position relative to the bright planets and the constellations of the zodiac? Your wish is granted, courtesy of Heavens-Above.com!

When the moon shows itself as a slender waxing crescent in Earth’s sky, then our planet beams a nearly-full waning gibbous Earth in the moon’s sky. The almost-full Earth, like a mirror, reflects sunlight and lights up the moon’s dark side. The moon, in turn, reflects sunlight back to Earth. Hence, that soft luminescence giving definition to the nighttime side of the moon is earthshine – twice-reflected sunlight. Look for soft glow of earthshine, with either the unaided eye or binoculars, on the dark side of the moon over the next several days.

View larger at EarthSky Community Photos. Peter Lowenstein of Mutare, Zimbabwe, caught the old waning crescent moon (and the planet Mercury to the moon’s lower right) in the east before sunrise December 25, 2019. To catch the upcoming young moon, look westward after sunset on December 27, 2019. Good luck! Thank you Peter!

Bottom line: Think photo opportunity this weekend (December 27-29, 2019) as the brightest and 2nd-brightest sky objects – the moon and Venus – beautify the evening twilight shortly after sunset.

from EarthSky https://ift.tt/351ddOC

Photos of December 26 ‘ring of fire’ eclipse

Get the details of this annular solar eclipse here.

View at EarthSky Community Photos. | Progression into and out of yesterday’s annular eclipse, from Tumon Bay, Guam. Eliot Herman reported: “It was a beautiful day in Guam to observe the eclipse mostly clear blue skies with a little marine haze on the coast. These images were captured with a Questar telescope and a Nikon D850 camera using a Baader solar filter.” Thank you, Eliot!

View at EarthSky Community Photos. | Dr Ski at Valencia, Philippines wrote: “The sun at maximum coverage from my location.” Thank you, Dr Ski!

View at EarthSky Community Photos. | Nikunj Rawal wrote from Jamnagar, Gujarat, India: “…73% maximum eclipse at 09:17 a.m. at Jamnagar, India on December 26. Was worth experience to witness and capture the phenomenon using a long-focal-length telephoto lens with well planned preparations of 2 weeks on top of the Gop Hills Mountain. The annular phase of this solar eclipse was not visible here, unlike South Indian states. This sequence is a combination of 2 consecutive exposures taken with the same camera using the same settings — one taken of the landscape and another of the background of sun using 3.8mm Baader filter.” Thank you, Nikunj!

View at EarthSky Community Photos. | Kannan A wrote from Singapore: “On this day – December 26, 2019 – in Singapore, we got to see the annular solar eclipse. It was a very rare moment on this day which coincided with Boxing Day and the 15th anniversary of the 2004 Tsunami in Banda Aceh. During the maximum phase of the eclipse, the clouds formed momentarily allowing stargazers to view the eclipse without the use of specialized equipment, but with precautions taken to protect the eyes. In the north of Singapore, Woodlands, however, I did not get to see the ring of fire but got a pleasant Christmas C!” Thank you, Kannan A!

View at EarthSky Community Photos. | A final word from Kannan A! Thank you!

Bottom line: Photos from the EarthSky Community of the December 26, 2019 annular or ‘ring of fire’ solar eclipse. The annular eclipse was viewed across a narrow track that started at sunrise in Saudi Arabia and ended at sunset over the North Pacific Ocean. Outside that track, many more viewed a partial eclipse.

Get the details of this annular solar eclipse here.

from EarthSky https://ift.tt/2SslIQg

Get the details of this annular solar eclipse here.

View at EarthSky Community Photos. | Progression into and out of yesterday’s annular eclipse, from Tumon Bay, Guam. Eliot Herman reported: “It was a beautiful day in Guam to observe the eclipse mostly clear blue skies with a little marine haze on the coast. These images were captured with a Questar telescope and a Nikon D850 camera using a Baader solar filter.” Thank you, Eliot!

View at EarthSky Community Photos. | Dr Ski at Valencia, Philippines wrote: “The sun at maximum coverage from my location.” Thank you, Dr Ski!

View at EarthSky Community Photos. | Nikunj Rawal wrote from Jamnagar, Gujarat, India: “…73% maximum eclipse at 09:17 a.m. at Jamnagar, India on December 26. Was worth experience to witness and capture the phenomenon using a long-focal-length telephoto lens with well planned preparations of 2 weeks on top of the Gop Hills Mountain. The annular phase of this solar eclipse was not visible here, unlike South Indian states. This sequence is a combination of 2 consecutive exposures taken with the same camera using the same settings — one taken of the landscape and another of the background of sun using 3.8mm Baader filter.” Thank you, Nikunj!

View at EarthSky Community Photos. | Kannan A wrote from Singapore: “On this day – December 26, 2019 – in Singapore, we got to see the annular solar eclipse. It was a very rare moment on this day which coincided with Boxing Day and the 15th anniversary of the 2004 Tsunami in Banda Aceh. During the maximum phase of the eclipse, the clouds formed momentarily allowing stargazers to view the eclipse without the use of specialized equipment, but with precautions taken to protect the eyes. In the north of Singapore, Woodlands, however, I did not get to see the ring of fire but got a pleasant Christmas C!” Thank you, Kannan A!

View at EarthSky Community Photos. | A final word from Kannan A! Thank you!

Bottom line: Photos from the EarthSky Community of the December 26, 2019 annular or ‘ring of fire’ solar eclipse. The annular eclipse was viewed across a narrow track that started at sunrise in Saudi Arabia and ended at sunset over the North Pacific Ocean. Outside that track, many more viewed a partial eclipse.

Get the details of this annular solar eclipse here.

from EarthSky https://ift.tt/2SslIQg