Zodiacal light glowing pyramid after dark

Moonless evenings in February, March and April present the best time of year to see zodiacal light in the Northern Hemisphere evening sky. Meanwhile, from the Southern Hemisphere, the zodiacal light is best seen before dawn during these months of the year. The light appears when the evening twilight has left the sky (about 80 to 120 minutes after sunset).

It looks like a hazy pyramid of light in the west after true darkness falls.

Scott Bouton didn’t wait until February, March or April to catch this great shot of the zodiacal light over Mauna Kea, Hawaii on January 15, 2018. Because Hawaii is closer to the equator, you’ll see the zodiacal light more frequently from there.

This light can be noticeable and easy to see from latitudes like those in the southern U.S. I’ve seen it many times from the latitude of southern Texas, sometimes while driving a lonely highway far from city lights, up to an hour or so after evening dusk leaves the sky.

In that case, the zodiacal light can resemble the lights of a city or town just over the horizon.

Skywatchers in the northern U.S. or Canada sometimes say wistfully that they’ve never seen the zodiacal light. On the other hand, sometimes the camera will pick up faint objects that the eye can’t see. And we’ve had reports of the zodiacal light visible to the eye by those at northerly latitudes.

View larger. | EarthSky Facebook friend Jim Peacock is in northern Wisconsin, which is farther to the north on Earth’s globe than usual for easy viewing of the light. Yet he caught this zodiacal light in February, 2013. He said: “Yes, it was very visible to the eye … it reached high above the horizon. Was so cool to see over Lake Superior.” You can also see the Circlet of Pisces to the lower right of center – and the Y-shaped Water Jar of the constellation Aquarius to the lower right of the Circlet, just above the sunlit cloud.

You definitely do need a dark sky location to see the zodiacal light, someplace where city lights aren’t obscuring the natural lights in the sky. Remember, the zodiacal light is a pyramid-shaped glow in the west after dark. It’s even “milkier” in appearance than the starlit trail of the summer Milky Way.

The light is most visible after dusk at this time of year because (as seen from the Northern Hemisphere) the ecliptic – or path of the sun, moon, and planets – stands nearly straight up with respect to the horizon after the sun sets in February and March.

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Maureen Allen in Yankeetown, Florida caught the zodiacal light (l) and Milky Way in February, 2016.

The zodiacal light can be seen for up to an hour after dusk. Unlike twilight dusk, though, there’s no rosy color to the zodiacal light. The reddish skies at dusk and dawn are caused by Earth’s atmosphere, and the zodiacal light originates far outside our atmosphere.

When you see the zodiacal light, you are looking edgewise into the plane of our own solar system. The zodiacal light is sunlight reflecting off dust particles that move in the same plane as Earth and the other planets orbiting our sun.

Remember, if you live in the Southern Hemisphere, your late winter/early spring months (August, September, October) are the best time for you to see the zodiacal light in the evening. Right now (February, March, April), you should be looking for the zodiacal light before dawn.

Bottom line: From the Northern Hemisphere, look for the elusive zodiacal light, a hazy pyramid of light extending up from the sunset point. Southern Hemisphere? Look before dawn!

Live by the moon with your 2017 EarthSky lunar calendar!

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Moonless evenings in February, March and April present the best time of year to see zodiacal light in the Northern Hemisphere evening sky. Meanwhile, from the Southern Hemisphere, the zodiacal light is best seen before dawn during these months of the year. The light appears when the evening twilight has left the sky (about 80 to 120 minutes after sunset).

It looks like a hazy pyramid of light in the west after true darkness falls.

Scott Bouton didn’t wait until February, March or April to catch this great shot of the zodiacal light over Mauna Kea, Hawaii on January 15, 2018. Because Hawaii is closer to the equator, you’ll see the zodiacal light more frequently from there.

This light can be noticeable and easy to see from latitudes like those in the southern U.S. I’ve seen it many times from the latitude of southern Texas, sometimes while driving a lonely highway far from city lights, up to an hour or so after evening dusk leaves the sky.

In that case, the zodiacal light can resemble the lights of a city or town just over the horizon.

Skywatchers in the northern U.S. or Canada sometimes say wistfully that they’ve never seen the zodiacal light. On the other hand, sometimes the camera will pick up faint objects that the eye can’t see. And we’ve had reports of the zodiacal light visible to the eye by those at northerly latitudes.

View larger. | EarthSky Facebook friend Jim Peacock is in northern Wisconsin, which is farther to the north on Earth’s globe than usual for easy viewing of the light. Yet he caught this zodiacal light in February, 2013. He said: “Yes, it was very visible to the eye … it reached high above the horizon. Was so cool to see over Lake Superior.” You can also see the Circlet of Pisces to the lower right of center – and the Y-shaped Water Jar of the constellation Aquarius to the lower right of the Circlet, just above the sunlit cloud.

You definitely do need a dark sky location to see the zodiacal light, someplace where city lights aren’t obscuring the natural lights in the sky. Remember, the zodiacal light is a pyramid-shaped glow in the west after dark. It’s even “milkier” in appearance than the starlit trail of the summer Milky Way.

The light is most visible after dusk at this time of year because (as seen from the Northern Hemisphere) the ecliptic – or path of the sun, moon, and planets – stands nearly straight up with respect to the horizon after the sun sets in February and March.

Donate: Your support means the world to us

Maureen Allen in Yankeetown, Florida caught the zodiacal light (l) and Milky Way in February, 2016.

The zodiacal light can be seen for up to an hour after dusk. Unlike twilight dusk, though, there’s no rosy color to the zodiacal light. The reddish skies at dusk and dawn are caused by Earth’s atmosphere, and the zodiacal light originates far outside our atmosphere.

When you see the zodiacal light, you are looking edgewise into the plane of our own solar system. The zodiacal light is sunlight reflecting off dust particles that move in the same plane as Earth and the other planets orbiting our sun.

Remember, if you live in the Southern Hemisphere, your late winter/early spring months (August, September, October) are the best time for you to see the zodiacal light in the evening. Right now (February, March, April), you should be looking for the zodiacal light before dawn.

Bottom line: From the Northern Hemisphere, look for the elusive zodiacal light, a hazy pyramid of light extending up from the sunset point. Southern Hemisphere? Look before dawn!

Live by the moon with your 2017 EarthSky lunar calendar!

from EarthSky http://ift.tt/1Dl4MtJ

Aerobraking down, down

There’s a nice update today from Spacecraft Operations Engineer Armelle Hubault, working on the ExoMars TGO flight control team at ESOC.

TGO aerobraking visualisation to March 2018. Credit: ESA

Armelle writes:

This graphic (above) gives a very concise visualisation of the fantastic progress we’ve made with aerobraking to date.

It was coded by my ExoMars TGO colleague Johannes Bauer; the bold grey lines show successive reductions in the ExoMars TGO orbital period by 1 hour; the thin lines by 30 mins.

We started on the biggest orbit with an apocentre (the furthest distance from Mars during each orbit) of 33 200 km and an orbit of 24 hr in March 2017, but had to pause last summer due to Mars being in conjunction.

We recommenced aerobraking in August 2017, and are on track to finish up in the final science orbit in mid-March 2018. As of today, 30 Jan 2018, we have slowed ExoMars TGO by 781.5 m/s

For comparison, this speed is more than twice as fast as the speed of a typical long-haul jet aircraft.

On Tuesday this week at 15:35 CET, the spacecraft was where the red dot is, coming out of pericentre passage (passing through the point of closest approach over the surface – where Mars’ thin, uppermost atmosphere drags on the craft the most to give the braking effect).

The blue line is the current orbit, which takes only 2 hrs and 48 min and with the apocentre reduced to 2700 km; the red shows the final aerobraking orbit we expect to achieve later in March. Then, we will use the thrusters to manoeuvre the spacecraft into the green orbit (roughly 400 km circular) – the final science and operational data relay orbit.

The image is pretty much to scale.

We have to adjust our pericentre height regularly, because on the one hand, the martian atmosphere varies in density (so sometimes we brake more and sometimes we brake less) and on the other hand, martian gravity is not the same everywhere (so sometimes the planet pulls us down and sometimes we drift out a bit). We try to stay at about 110 km altitude for optimum braking effect.

To keep the spacecraft on track, we upload a new set of commands every day – so for us, for flight dynamics and for the ground station teams, it’s a very demanding time!

When TGO skims through the atmosphere, it has to adopt a specific orientation to optimise the braking effect and to make sure it stays stable and does not start to spin madly, which would not be optimal.

We are basically using the solar panels as ‘wings’ to slow us down and circularise the orbit.

Tracking aerobraking progress. Credit: ESA

The main challenge at the moment is that, since we never know in advance how much the spacecraft is going to be slowed during each pericentre passage, we also never know exactly when it is going to reestablish contact with our ground stations after pointing back to Earth.

We are working with a 20-min ‘window’ for acquisition of signal (AOS), when the ground station first catches TGO’s signal during any given station visibility, whereas normally for interplanetary missions we have a firm AOS time programmed in advance.

With the current orbital period now just below 3 hrs, we go through this little exercise 8 times per day!

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v

There’s a nice update today from Spacecraft Operations Engineer Armelle Hubault, working on the ExoMars TGO flight control team at ESOC.

TGO aerobraking visualisation to March 2018. Credit: ESA

Armelle writes:

This graphic (above) gives a very concise visualisation of the fantastic progress we’ve made with aerobraking to date.

It was coded by my ExoMars TGO colleague Johannes Bauer; the bold grey lines show successive reductions in the ExoMars TGO orbital period by 1 hour; the thin lines by 30 mins.

We started on the biggest orbit with an apocentre (the furthest distance from Mars during each orbit) of 33 200 km and an orbit of 24 hr in March 2017, but had to pause last summer due to Mars being in conjunction.

We recommenced aerobraking in August 2017, and are on track to finish up in the final science orbit in mid-March 2018. As of today, 30 Jan 2018, we have slowed ExoMars TGO by 781.5 m/s

For comparison, this speed is more than twice as fast as the speed of a typical long-haul jet aircraft.

On Tuesday this week at 15:35 CET, the spacecraft was where the red dot is, coming out of pericentre passage (passing through the point of closest approach over the surface – where Mars’ thin, uppermost atmosphere drags on the craft the most to give the braking effect).

The blue line is the current orbit, which takes only 2 hrs and 48 min and with the apocentre reduced to 2700 km; the red shows the final aerobraking orbit we expect to achieve later in March. Then, we will use the thrusters to manoeuvre the spacecraft into the green orbit (roughly 400 km circular) – the final science and operational data relay orbit.

The image is pretty much to scale.

We have to adjust our pericentre height regularly, because on the one hand, the martian atmosphere varies in density (so sometimes we brake more and sometimes we brake less) and on the other hand, martian gravity is not the same everywhere (so sometimes the planet pulls us down and sometimes we drift out a bit). We try to stay at about 110 km altitude for optimum braking effect.

To keep the spacecraft on track, we upload a new set of commands every day – so for us, for flight dynamics and for the ground station teams, it’s a very demanding time!

When TGO skims through the atmosphere, it has to adopt a specific orientation to optimise the braking effect and to make sure it stays stable and does not start to spin madly, which would not be optimal.

We are basically using the solar panels as ‘wings’ to slow us down and circularise the orbit.

Tracking aerobraking progress. Credit: ESA

The main challenge at the moment is that, since we never know in advance how much the spacecraft is going to be slowed during each pericentre passage, we also never know exactly when it is going to reestablish contact with our ground stations after pointing back to Earth.

We are working with a 20-min ‘window’ for acquisition of signal (AOS), when the ground station first catches TGO’s signal during any given station visibility, whereas normally for interplanetary missions we have a firm AOS time programmed in advance.

With the current orbital period now just below 3 hrs, we go through this little exercise 8 times per day!

from Rocket Science http://ift.tt/2BLe2ws
v

These 2 stars in Scorpius are harbingers of spring

Shaula and Lesath. Photo via John Glossop.

Tomorrow – February 2, 2018 – is Groundhog Day, the day on which the legendary groundhog seeks his shadow as a forecast of whether spring will come early or late. Whatever the groundhog says … you can look east before dawn now for another sign of spring. It’s the two stars that represent the Stinger in the constellation Scorpius the Scorpion. We call them Shaula and Lesath. From mid-northern latitudes, in the cold dawn of February, the sighting of these stars announces that the winter landscape is about to awaken from its long dormant slumber: that spring is on its way.

For the Pawnee, who roamed the prairie lands of Kansas and Nebraska, the sky was a calendar, and the stars foretold the change of seasons. The Pawnee saw a snake in the stars forming the front part of Scorpius. But the stars of the stinger were, for the Pawnee, a pair of ducks.

It’s thought that the Pawnee called the stars on the Scorpion’s stinger the Swimming Duck stars. When the Swimming Ducks came into view in the southeast – prior to daybreak in the month of February – the Pawnee recognized that it was time to begin planting ceremonies. In other words, they were a sign of hope, and a sign that spring was on its way.

In a dark sky, you can see that the starlit band of the Milky Way runs behind Shaula and Lesath in the Tail of Scorpius. Photo via Daniel McVey. Visit his website.

These stars are now coming into view at or shortly before dawn.

You’ll need a clear, unobstructed view to the south to southeast to spot Scorpius’ stinger stars – Shaula and Lesath – flickering by the horizon. If you miss seeing these stars tomorrow, or the next day, try again later in February.

If you’re in the Northern Hemisphere, Shaula and Lesath will come over your southeastern horizon before dawn sometime this month. They’re a hopeful sign that spring is coming.

In some respects, we can regard the search for the Swimming Duck stars as a Pawnee version of Groundhog Day.

The return of the Swimming Ducks to the morning sky signaled the first stirrings of the great plains from hibernation. Shaula and Lesath’s presence over the horizon was symbolic of waterfowl breaking through the ice.

As we approach the end of winter, Shaula and Lesath will appear higher each morning in the southeast before dawn. Their morning appearance tells us that the prairie is about to awaken to the rolling thunders of spring.

By the way, for us today, the stars at the end of the Scorpion’s tail are also known as the Cat’s Eyes. They’re easy to spot at the J-shaped star pattern that forms the constellation Scorpius.

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

Bottom line: Go ahead. Treat yourself to something beautiful, and hopeful. Get up early on some morning this February, and look for the Scorpion’s stinger stars near the horizon.

from EarthSky http://ift.tt/16kLBGt

Shaula and Lesath. Photo via John Glossop.

Tomorrow – February 2, 2018 – is Groundhog Day, the day on which the legendary groundhog seeks his shadow as a forecast of whether spring will come early or late. Whatever the groundhog says … you can look east before dawn now for another sign of spring. It’s the two stars that represent the Stinger in the constellation Scorpius the Scorpion. We call them Shaula and Lesath. From mid-northern latitudes, in the cold dawn of February, the sighting of these stars announces that the winter landscape is about to awaken from its long dormant slumber: that spring is on its way.

For the Pawnee, who roamed the prairie lands of Kansas and Nebraska, the sky was a calendar, and the stars foretold the change of seasons. The Pawnee saw a snake in the stars forming the front part of Scorpius. But the stars of the stinger were, for the Pawnee, a pair of ducks.

It’s thought that the Pawnee called the stars on the Scorpion’s stinger the Swimming Duck stars. When the Swimming Ducks came into view in the southeast – prior to daybreak in the month of February – the Pawnee recognized that it was time to begin planting ceremonies. In other words, they were a sign of hope, and a sign that spring was on its way.

In a dark sky, you can see that the starlit band of the Milky Way runs behind Shaula and Lesath in the Tail of Scorpius. Photo via Daniel McVey. Visit his website.

These stars are now coming into view at or shortly before dawn.

You’ll need a clear, unobstructed view to the south to southeast to spot Scorpius’ stinger stars – Shaula and Lesath – flickering by the horizon. If you miss seeing these stars tomorrow, or the next day, try again later in February.

If you’re in the Northern Hemisphere, Shaula and Lesath will come over your southeastern horizon before dawn sometime this month. They’re a hopeful sign that spring is coming.

In some respects, we can regard the search for the Swimming Duck stars as a Pawnee version of Groundhog Day.

The return of the Swimming Ducks to the morning sky signaled the first stirrings of the great plains from hibernation. Shaula and Lesath’s presence over the horizon was symbolic of waterfowl breaking through the ice.

As we approach the end of winter, Shaula and Lesath will appear higher each morning in the southeast before dawn. Their morning appearance tells us that the prairie is about to awaken to the rolling thunders of spring.

By the way, for us today, the stars at the end of the Scorpion’s tail are also known as the Cat’s Eyes. They’re easy to spot at the J-shaped star pattern that forms the constellation Scorpius.

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

Bottom line: Go ahead. Treat yourself to something beautiful, and hopeful. Get up early on some morning this February, and look for the Scorpion’s stinger stars near the horizon.

from EarthSky http://ift.tt/16kLBGt

Army advances PTSD, other cognitive research through latest partnership

The U.S. Army Research Laboratory and Helius Medical Technologies, Inc. have partnered to expand on early research that could mean new interventions for improving military readiness and resilience, as well as reducing symptoms of post-traumatic stress disorder.

from http://ift.tt/2nzgZef

The U.S. Army Research Laboratory and Helius Medical Technologies, Inc. have partnered to expand on early research that could mean new interventions for improving military readiness and resilience, as well as reducing symptoms of post-traumatic stress disorder.

from http://ift.tt/2nzgZef

Mount Sharp photobombs Mars rover selfie

View larger. | The Curiosity Mars rover appears to be looking at its own camera, in this mosaic image. Behind it is Mount Sharp, photobombing the robot’s selfie. Image via NASA/JPL-Caltech/MSSS.

NASA released this self-portrait of its Curiosity rover on January 31, 2018. This selfie of the rover is actually a actually assembled from dozens of images taken by Curiosity’s Mars Hands Lens Imager (MAHLI). The imager acquired all of these shots on January 23, 2018, during Sol 1943. NASA said it:

… shows the vehicle on Vera Rubin Ridge, which it’s been investigating for the past several months. Directly behind the rover is the start of a clay-rich slope scientists are eager to begin exploring. In the coming week, Curiosity will begin to climb this slope. North is on the left and west is on the right, with Gale Crater’s rim on the horizon of both edges.

Poking up just behind Curiosity’s mast is Mount Sharp, photobombing the robot’s selfie. Curiosity landed on Mars five years ago with the intention of studying lower Mount Sharp, where it will remain for all of its time on Mars. The mountain’s base provides access to layers formed over millions of years. These layers formed in the presence of water — likely due to a lake or lakes that sat at the bottom of the mountain, which sits inside Gale Crater.

Here’s how Curiosity acquires its own selfie, without its robot arm showing

Read more about the rover’s January 2018 selfie

For news about other Mars missions this month, view the first episode of a new video series, The Mars Report.

Bottom line: Mars’ Mount Sharp – whose flanks are the focus of the Curiosity rover’s studies on Mars – photobombed this January 2018 selfie of the rover.

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View larger. | The Curiosity Mars rover appears to be looking at its own camera, in this mosaic image. Behind it is Mount Sharp, photobombing the robot’s selfie. Image via NASA/JPL-Caltech/MSSS.

NASA released this self-portrait of its Curiosity rover on January 31, 2018. This selfie of the rover is actually a actually assembled from dozens of images taken by Curiosity’s Mars Hands Lens Imager (MAHLI). The imager acquired all of these shots on January 23, 2018, during Sol 1943. NASA said it:

… shows the vehicle on Vera Rubin Ridge, which it’s been investigating for the past several months. Directly behind the rover is the start of a clay-rich slope scientists are eager to begin exploring. In the coming week, Curiosity will begin to climb this slope. North is on the left and west is on the right, with Gale Crater’s rim on the horizon of both edges.

Poking up just behind Curiosity’s mast is Mount Sharp, photobombing the robot’s selfie. Curiosity landed on Mars five years ago with the intention of studying lower Mount Sharp, where it will remain for all of its time on Mars. The mountain’s base provides access to layers formed over millions of years. These layers formed in the presence of water — likely due to a lake or lakes that sat at the bottom of the mountain, which sits inside Gale Crater.

Here’s how Curiosity acquires its own selfie, without its robot arm showing

Read more about the rover’s January 2018 selfie

For news about other Mars missions this month, view the first episode of a new video series, The Mars Report.

Bottom line: Mars’ Mount Sharp – whose flanks are the focus of the Curiosity rover’s studies on Mars – photobombed this January 2018 selfie of the rover.

from EarthSky http://ift.tt/2DPBj21

View of Mars rover’s journey so far

Curiosity Project Scientist Ashwin Vasavada gives a descriptive tour of the Mars rover’s view in Gale Crater. The *white-balanced scene looks back over the journey so far. The view from Vera Rubin Ridge looks back over buttes, dunes and other features along the route. See where the rover is now. *To aid geologists, colors in the image are white-balanced so rocks appear the same color as the same rocks would on Earth. Why? Click here.

NASA’s Curiosity Mars rover took the panoramic image (below) from Vera Rubin Ridge on the north flank of the planet’s Mount Sharp. The view encompasses much of the 11-mile (18-km) route the rover has driven from its 2012 landing site, all inside Gale Crater. One hill on the northern horizon is about 50 miles (about 85 km) away, well outside the crater, though most of the scene’s horizon is the crater’s northern rim, roughly one-third that distance away and 1.2 miles (two km) above the rover.

Image via NASA/JPL.

View the image (much) larger.

Curiosity’s Mast Camera, or Mastcam, took the component images of the panorama on October 25, 2017, during the 1,856th Martian day, or sol, of the rover’s work on Mars. At that point, Curiosity had gained 1,073 feet (327 meters) in elevation and driven 10.95 miles (17.63 km) from its landing site. The mission has subsequently approached the southern edge of Vera Rubin Ridge and examined several outcrop locations along the way.

This image indicates the the initial portion of the rover’s approximate path since it landed at Bradbury Landing in 2012, including investigation sites Yellowknife Bay, Darwin and Cooperstown. The rover’s exact landing site is hidden behind a slight rise. The heat shield, back shell, and parachute used during the spacecraft’s descent are within the pictured area but not recognizable due to the distance and to camouflaging by dust. At Yellowknife Bay in 2013, the mission found evidence of an ancient freshwater-lake environment that offered all of the basic chemical ingredients for microbial life. Image via NASA/JPL.

Last week, the Curiosity team on Earth received copious new images from the rover through a record-setting relay by NASA’s MAVEN orbiter – surpassing a gigabit of data during a single relay session from Mars for the first time in history.

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

Bottom line: A panoramic image that NASA’s Curiosity Mars rover took in from a mountainside ridge in October 2017 shows key sites the rover’s visited since its 2012 landing.

Read more from NASA/JPL

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Curiosity Project Scientist Ashwin Vasavada gives a descriptive tour of the Mars rover’s view in Gale Crater. The *white-balanced scene looks back over the journey so far. The view from Vera Rubin Ridge looks back over buttes, dunes and other features along the route. See where the rover is now. *To aid geologists, colors in the image are white-balanced so rocks appear the same color as the same rocks would on Earth. Why? Click here.

NASA’s Curiosity Mars rover took the panoramic image (below) from Vera Rubin Ridge on the north flank of the planet’s Mount Sharp. The view encompasses much of the 11-mile (18-km) route the rover has driven from its 2012 landing site, all inside Gale Crater. One hill on the northern horizon is about 50 miles (about 85 km) away, well outside the crater, though most of the scene’s horizon is the crater’s northern rim, roughly one-third that distance away and 1.2 miles (two km) above the rover.

Image via NASA/JPL.

View the image (much) larger.

Curiosity’s Mast Camera, or Mastcam, took the component images of the panorama on October 25, 2017, during the 1,856th Martian day, or sol, of the rover’s work on Mars. At that point, Curiosity had gained 1,073 feet (327 meters) in elevation and driven 10.95 miles (17.63 km) from its landing site. The mission has subsequently approached the southern edge of Vera Rubin Ridge and examined several outcrop locations along the way.

This image indicates the the initial portion of the rover’s approximate path since it landed at Bradbury Landing in 2012, including investigation sites Yellowknife Bay, Darwin and Cooperstown. The rover’s exact landing site is hidden behind a slight rise. The heat shield, back shell, and parachute used during the spacecraft’s descent are within the pictured area but not recognizable due to the distance and to camouflaging by dust. At Yellowknife Bay in 2013, the mission found evidence of an ancient freshwater-lake environment that offered all of the basic chemical ingredients for microbial life. Image via NASA/JPL.

Last week, the Curiosity team on Earth received copious new images from the rover through a record-setting relay by NASA’s MAVEN orbiter – surpassing a gigabit of data during a single relay session from Mars for the first time in history.

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

Bottom line: A panoramic image that NASA’s Curiosity Mars rover took in from a mountainside ridge in October 2017 shows key sites the rover’s visited since its 2012 landing.

Read more from NASA/JPL

from EarthSky http://ift.tt/2nrKIXv

Moon and Regulus on February 1

Tonight – February 1, 2018 – the full-looking waning gibbous moon moon closely partners with Regulus, brightest star in the constellation Leo the Lion. Look for them in the east at nightfall or early evening. They climb highest up for the night at roughly 1 a.m. local time and sit low in the west as darkness gives way to dawn on February 2.

The moon most recently turned full on January 31 at 13:27 Universal Time. It won’t turn full again until March 2 at 0:51 Universal Time. That means no full moon in February 2018 at all, but two full moons in January 2018 and March 2018. The second of two full moons to occur in a single calendar month is popularly called a Blue Moon.

From North America, we see the waning gibbous moon to the east (below) Regulus. However, as seen from Europe and Asia, the moon appears higher up relative to Regulus. In fact, if you’re at just the right spot on Earth, the moon will actually occult (cover over) Regulus for a portion of the night tonight.

The February 1, 2018 occultation of Regulus appears in the sky from Australia, Wilkes Land, and New Zealand.

This occultation is part of a series of monthly lunar occultations of Regulus that started on December 18, 2016. The series will continue until its conclusion on April 24, 2018.

Who will see the occultation of Regulus on February 1, 2018? Details via IOTA.

The moon and Regulus go westward during the night for the same reason that the sun travels westward across the sky during the day. The Earth spins from west-to-east on its rotational axis, making it appear as if the sun, moon, planets and stars move westward across the sky while the Earth stays still.

In fact, of course, it’s the Earth that’s spinning, causing that westward shift, and, meanwhile, the moon’s orbital direction is always eastward, or toward the sunrise direction, in our sky.

Note the moon’s position relative to Regulus tonight. Then note its position relative to Regulus tomorrow night – or 24 hours later. The moon’s change of position in front of the background stars lets you know how far the moon revolves around our planet Earth in one day.

Regulus is well known for its extremely fast rate of spin. Our sun takes nearly four weeks to complete one spin on its axis. In contrast, Regulus spins full circle once every 16 hours. This star has an equatorial diameter that’s 4.3 times greater than the sun’s but it still rotates at 700,000 miles (1,100,000 km) per hour.

At that speed, you could reach the moon in a little over 20 minutes!

Regulus is the brightest star in Leo the Lion. Here’s how to find Leo anytime. An imaginary line drawn between the pointer stars in the Big Dipper – the two outer stars in the Dipper’s bowl – points in one direction toward Polaris, the North Star, and in the opposite direction toward Leo.

Bottom line: Enjoy the pairing of the waning gibbous moon and Regulus – brightest star in Leo the Lion – on February 1, 2018! From some places the moon will pass in front of (occult) Regulus.

Live by the moon with your 2018 EarthSky lunar calendar!

Donate: Your support means the world to us

from EarthSky http://ift.tt/2kwleo8

Tonight – February 1, 2018 – the full-looking waning gibbous moon moon closely partners with Regulus, brightest star in the constellation Leo the Lion. Look for them in the east at nightfall or early evening. They climb highest up for the night at roughly 1 a.m. local time and sit low in the west as darkness gives way to dawn on February 2.

The moon most recently turned full on January 31 at 13:27 Universal Time. It won’t turn full again until March 2 at 0:51 Universal Time. That means no full moon in February 2018 at all, but two full moons in January 2018 and March 2018. The second of two full moons to occur in a single calendar month is popularly called a Blue Moon.

From North America, we see the waning gibbous moon to the east (below) Regulus. However, as seen from Europe and Asia, the moon appears higher up relative to Regulus. In fact, if you’re at just the right spot on Earth, the moon will actually occult (cover over) Regulus for a portion of the night tonight.

The February 1, 2018 occultation of Regulus appears in the sky from Australia, Wilkes Land, and New Zealand.

This occultation is part of a series of monthly lunar occultations of Regulus that started on December 18, 2016. The series will continue until its conclusion on April 24, 2018.

Who will see the occultation of Regulus on February 1, 2018? Details via IOTA.

The moon and Regulus go westward during the night for the same reason that the sun travels westward across the sky during the day. The Earth spins from west-to-east on its rotational axis, making it appear as if the sun, moon, planets and stars move westward across the sky while the Earth stays still.

In fact, of course, it’s the Earth that’s spinning, causing that westward shift, and, meanwhile, the moon’s orbital direction is always eastward, or toward the sunrise direction, in our sky.

Note the moon’s position relative to Regulus tonight. Then note its position relative to Regulus tomorrow night – or 24 hours later. The moon’s change of position in front of the background stars lets you know how far the moon revolves around our planet Earth in one day.

Regulus is well known for its extremely fast rate of spin. Our sun takes nearly four weeks to complete one spin on its axis. In contrast, Regulus spins full circle once every 16 hours. This star has an equatorial diameter that’s 4.3 times greater than the sun’s but it still rotates at 700,000 miles (1,100,000 km) per hour.

At that speed, you could reach the moon in a little over 20 minutes!

Regulus is the brightest star in Leo the Lion. Here’s how to find Leo anytime. An imaginary line drawn between the pointer stars in the Big Dipper – the two outer stars in the Dipper’s bowl – points in one direction toward Polaris, the North Star, and in the opposite direction toward Leo.

Bottom line: Enjoy the pairing of the waning gibbous moon and Regulus – brightest star in Leo the Lion – on February 1, 2018! From some places the moon will pass in front of (occult) Regulus.

Live by the moon with your 2018 EarthSky lunar calendar!

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