Sky - Blog Posts
Save the Date: 2024 Total Solar Eclipse
On April 8, 2024, a total solar eclipse will travel through Mexico, cross the United States from Texas to Maine, and exit North America along Canada’s Atlantic coast. A total solar eclipse occurs when the Moon passes between the Sun and the Earth, completely blocking the face of the Sun. The sky will darken as if it were dawn or dusk.
Weather permitting, people throughout most of North and Central America, including all of the contiguous United States, will be able to view at least a partial solar eclipse. A partial solar eclipse is when the Moon only covers part of the Sun. People in Hawaii and parts of Alaska will also experience a partial solar eclipse. Click here to learn more about when and where the solar eclipse will be visible: go.nasa.gov/Eclipse2024Map
Not in the path of the eclipse? Join us online to watch the eclipse with NASA. Set a reminder to watch live: https://go.nasa.gov/3V2CQML
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A Geminid meteor streaks across the sky as the Soyuz TMA-19M spacecraft is rolled out by train to the launch pad at the Baikonur Cosmodrome on Sunday, Dec. 13, 2015, in Kazakhstan. Credit: NASA/Joel Kowsky
Make a Wish! How to See the Geminid Meteor Shower
Every December, we have a chance to see one of our favorite meteor showers – the Geminids. To help you prepare, we’ve answered some of your most commonly asked questions. Happy viewing, stargazers!
These radar images of near-Earth object 3200 Phaethon were generated by astronomers at the National Science Foundation's Arecibo Observatory on Dec. 17, 2017. Observations of Phaethon were conducted at Arecibo from Dec. 15 through 19, 2017. At time of closest approach on Dec. 16 at 3 p.m. PST (6 p.m. EST, 2300 UTC), the asteroid was about 6.4 million miles (10.3 million kilometers) away, or about 27 times the distance from Earth to the Moon. Credit: Arecibo Observatory/NASA/NSF
What are the Geminids?
The Geminids are caused by debris from a celestial object known as 3200 Phaethon striking Earth’s atmosphere. Phaethon’s origin is the subject of some debate. Some astronomers consider it to be an extinct comet, based on observations showing some small amount of material leaving its surface. Others argue that it has to be an asteroid because of its orbit and its similarity to the main-belt asteroid Pallas.
All meteors appear to come from the same place in the sky, which is called the radiant. The Geminids appear to radiate from a point in the constellation Gemini, hence the name “Geminids.” The graphic shows the radiants of 388 meteors with speeds of 35 km/s observed by the NASA Fireball Network in December 2020. All the radiants are in Gemini, which means they belong to the Geminid shower. Credit: NASA
Why are they called the Geminids?
All meteors associated with a shower have similar orbits, and they all appear to come from the same place in the sky, which is called the radiant. The Geminids appear to radiate from a point in the constellation Gemini, hence the name “Geminids.”
A Geminid streaks across the sky in this photo from December 2019. Credit: NASA
When is the best time to view them?
The Geminid meteor shower is active for much of December, but the peak will occur during the night of Dec. 13 into the morning of Dec. 14, 2023. Meteor rates in rural areas can be upwards of one per minute this year with minimal moonlight to interfere.
What do I need to see them?
As with all meteor showers, all you need is a clear sky, darkness, a bit of patience, and perhaps warm outerwear and blankets for this one. You don’t need to look in any particular direction, as meteors can generally be seen all over the sky. If you want to take photographs, check out these helpful tips.
An infographic based on 2019’s meteor camera data for the Geminids. Credit: NASA
Do you have any advice to help me see the Geminids better?
Find the darkest place you can and give your eyes about 30 minutes to adapt to the dark. Avoid looking at your cell phone, as it will disrupt your night vision. Lie flat on your back and look straight up, taking in as much sky as possible.
A Geminid streaks across the sky in this photo from December 2011. Credit: NASA
What will the meteors look like?
According to Bill Cooke, lead for the Meteoroid Environment Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, “Most meteors appear to be colorless or white, however the Geminids appear with a greenish hue. They’re pretty meteors!” Depending on the meteor’s chemical composition, the meteor will emit different colors when burned in the Earth’s atmosphere. Oxygen, magnesium, and nickel usually produce green.
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Don’t Say “Bye, Bye, Bye” To Your Vision: Solar Eclipse Safety Tips
On Oct. 14, 2023, many people across North, Central, and South America will have an opportunity to view a “ring of fire” eclipse – an annular solar eclipse – when the Moon passes between the Earth and Sun! During an annular eclipse, it is never safe to look directly at the Sun without specialized eye protection designed for solar viewing. To spread the word, *NSYNC's Lance Bass stopped by to share some tips on how to stay safe while viewing a solar eclipse.
Check out these detailed viewing maps to see if you will be able to see the entire or partial solar eclipse. If you are, make sure your solar viewing glasses have the ISO certification 12312-2. You can also check with local libraries or science museums to see if they have safe solar viewing glasses to hand out. You can also make a simple pinhole camera at home with some paper and aluminum foil: go.nasa.gov/pinholeprojector
Everyone online can watch the eclipse with NASA. Set a reminder to watch live: https://www.youtube.com/watch?v=LlY79zjud-Q
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June 10 Solar Eclipse in the Northern Hemisphere!
On June 10, people in parts of the northern hemisphere will have the chance to witness a solar eclipse.
Watch the full visualization of the eclipse.
The June 10 eclipse is an annular solar eclipse, meaning that the Sun will never be completely covered by the Moon. The Moon’s orbit around the Earth is not a perfect circle, so throughout each month, the Moon’s distance from Earth varies. During an annular eclipse, the Moon is far enough away from Earth that the Moon appears smaller than the Sun in the sky. Since the Moon does not block the entire view of the Sun, it will look like a dark disk on top of a larger, bright disk. This creates what looks like a ring of fire around the Moon.
People in the narrow path of annularity — which, for this eclipse, cuts through Canada, Greenland, and northern Russia — will see the ring of fire effect as the Moon passes across the Sun.
Credit: Dale Cruikshank
Outside this path of annularity, many people in the northern hemisphere have a chance to see a partial solar eclipse. The partial eclipse will fall on parts of the eastern United States, as well as northern Alaska. Some locations will only see a very small piece of the Sun covered, while locations closer to the path of annularity can see the Moon cover most of the Sun.
To learn which times the eclipse may be visible in certain areas, you can click anywhere on the map here. (Note that the maximum obscuration and maximum eclipse timing noted on this map may occur before sunrise in many locations.)
This solar eclipse is a pair with the total lunar eclipse that happened on May 26.
Both solar and lunar eclipses happen when the Sun, Moon, and Earth line up in the same plane — a lunar eclipse happens when Earth is in the middle and casts its shadow on the Moon, and a solar eclipse happens when the Moon is in the middle and casts its shadow on Earth. The Moon’s orbit is tilted, so it’s usually too high or too low for this alignment to work out.
The May 26 lunar eclipse was a supermoon lunar eclipse, meaning that the full moon happened while the Moon was near its closest point to Earth, making the Moon appear larger in the sky. The solar eclipse happens at the opposite point of the Moon’s orbit, during the new moon — and in this case, the new moon happens near the Moon’s farthest point from Earth, making the Moon appear smaller and resulting in an annular (rather than total) solar eclipse.
How to watch the eclipse
From anywhere: Watch the eclipse online with us! Weather permitting, we’ll be sharing live telescope views of the partial eclipse courtesy of Luc Boulard of the Royal Astronomical Society of Canada Sudbury Centre. Tune in starting at 5 a.m. EDT on June 10 at nasa.gov/live.
From the path of the annular or partial eclipse: Be sure to take safety precuations if you plan to watch in person!
It is never safe to look directly at the Sun's rays, even if the Sun is partly or mostly obscured, like during a partial or annular eclipse — doing so can severely harm your eyes. If you’re planning to watch the eclipse on June 10, you should use solar viewing glasses or an indirect viewing method at all points during the eclipse if you want to face the Sun. Solar viewing glasses, sometimes called eclipse glasses, are NOT regular sunglasses; regular sunglasses are not safe for viewing the Sun.
If you don’t have solar viewing or eclipse glasses, you can use an alternate indirect method like a pinhole projector. Pinhole projectors shouldn’t be used to look at the Sun; instead, they’re an easy way to project an image of the Sun onto a surface. Read more about how to create a pinhole projector.
This is a sunrise eclipse in the contiguous U.S. At locations in the lower 48 states that can see the partial eclipse, the show starts before sunrise, when the Sun is still below the horizon. That means the best chance to see the eclipse in these locations will be during and shortly after sunrise, when the Sun is very low in the sky. In northern Alaska, the eclipse happens in the very early hours of June 10 when the Sun is low on the horizon.
Bottom line: If you’re trying to watch the eclipse in the contiguous U.S., look for a location with a clear view of the horizon to the northeast, and plan to watch starting at sunrise with your solar filter or indirect viewer.
The next two eclipses in the continental U.S. are in 2023 and 2024. The annular solar eclipse of Oct. 14, 2023, will cut from Oregon to Texas, and the total solar eclipse of April 8, 2024, will pass from Texas to Maine. Keep up with the latest on eclipses and eclipse science at nasa.gov/eclipse.
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Get Ready Stargazers: The Geminids Are Here!
The Geminid meteor shower, one of the biggest meteor showers of the year, will peak this weekend, December 13 to 14. We get a lot of questions about the Geminids—so we’ve put together some answers to the ones we’re most commonly asked. Take a look!
What are the Geminids?
The Geminids are pieces of debris from an asteroid called 3200 Phaethon. Earth runs into Phaethon’s debris stream every year in mid-December, causing meteors to fly from the direction of the constellation Gemini – hence the name “Geminids.”
Image Credit: Arecibo Observatory/NASA/NSF
When is the best time to view them?
This year, the peak is during the overnight hours of December 13 and into the morning of December 14. Viewing should still be good on the night of December 14 into the early morning hours of the 15th. Weather permitting, the Geminids can be viewed from around midnight to 4 a.m. local time. The best time to see them is around 2 a.m. your local time on December 14, when the Geminid radiant is highest in your night sky. The higher the radiant – the celestial point in the sky from which meteors appear to originate – rises into the sky, the more meteors you are likely to see.
Image Credit & Copyright: Jeff Dai
What is the best way to see them?
Find the darkest place you can and give your eyes about 30 minutes to adapt to the dark. Avoid looking at your cell phone, as it will disrupt your night vision. Lie flat on your back and look straight up, taking in as much sky as possible. You will soon start to see the Geminid meteors!
Image Credit: NASA/Bill Dunford
Can you see the Geminids from anywhere in the world?
The Geminids are best observed in the Northern Hemisphere, but no matter where you are in the world (except Antarctica), some Geminids will be visible.
Image Credit: Jimmy Westlake
How many Geminids can I expect to see?
Under dark, clear skies, the Geminids can produce up to 120 meteors per hour – but this year, a bright, nearly full moon will hinder observations of the shower. Still, observers can hope to see up to 30 meteors per hour. Happy viewing!
Image Credit & Copyright: Yuri Beletsky
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Image Credit:NASA/JPL-Caltech
In this large celestial mosaic, our Spitzer Space Telescope captured a stellar family portrait! You can find infants, parents and grandparents of star-forming regions all in this generational photo. There’s a lot to see in this image, including multiple clusters of stars born from the same dense clumps of gas and dust – some older and more evolved than others. Dive deeper into its intricacies by visiting https://go.nasa.gov/2XpiWLf
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55 Cancri e: Where Skies Sparkle Above a Never-ending Ocean of Lava
We’ve discovered thousands of exoplanets – planets beyond our solar system – so far. These worlds are mysterious, but observations from telescopes on the ground and in space help us understand what they might look like.
Take the planet 55 Cancri e, for instance. It’s relatively close, galactically speaking, at 41 light-years away. It’s a rocky planet, nearly two times bigger than Earth, that whips around its star every 18 hours (as opposed to the 365 days it takes our planet to orbit the Sun. Slacker).
The planet’s star, 55 Cancri, is slightly smaller than our Sun, but it’s 65 times closer than the Sun is to Earth. Imagine a massive sun on the horizon! Because 55 Cancri e is so close to its star, it’s tidally locked just like our Moon is to the Earth. One side is always bathed in daylight, the other is in perpetual darkness. It’s also hot. Really hot. So hot that silicate rocks would melt into a molten ocean of melted rock. IT’S COVERED IN AN OCEAN OF LAVA. So, it’s that hot (between 3,140 degrees and 2,420 degrees F).
Scientists think 55 Cancri e also may harbor a thick atmosphere that circulates heat from the dayside to the nightside. Silicate vapor in the atmosphere could condense into sparkling clouds on the cooler, darker nightside that would reflect the lava below. It’s also possible that it would rain sand on the nightside, but … sparkling skies!
Check out our Exoplanet Travel Bureau's latest 360-degree visualization of 55 Cancri e and download the travel poster at https://go.nasa.gov/2HOyfF3.
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10 Ground-breaking Earth Satellite Images from 2018
In 2018, our satellites captured beautiful imagery from throughout the solar system and beyond. However, some of our favorite visualizations are of this very planet. While this list is by no means exhaustive, it does capture some Earth satellite images from this year that are both visually striking as well as scientifically informative. This list also represents a broad variety of Earth’s features, as well as satellite instrumentation. Take a journey with our eyes in the sky!
10. Hurricane Florence
Before making landfall, Hurricane Florence churned in the Atlantic for a full two weeks — making it among the longest-lived cyclones of the 2018 season. When it finally did hit land on Sep. 14, the storm devastated the southeastern U.S. coast with intense winds, torrential rains and severe flooding.
This natural-color image was acquired by MODIS on the Terra Satellite on Sep. 12, 2018.
Images like this, as well as other satellite information, were used to anticipate the impact of the storm. Our Disasters Program created flood proxy maps that were shared with the Federal Emergency Management Agency (FEMA) and the National Guard to estimate how many and which communities would be most affected by the storm, in order to help prepare recovery efforts ahead of time.
9. Australia’s Lake Eyre Basin
The Lake Eyre Basin covers one-sixth of Australia and is one of the world’s largest internally draining river systems. However, the rivers supported by this system are ephemeral, meaning that they only run for short periods of time following unpredictable rain — the rest of the time, the Basin is a dry, arid desert.
However, when the heavy rain comes, the basin erupts in an explosion of green. In this false-color image captured by the Operational Land Imager (OLI) on Landsat 8 on Apr. 25, 2018, you can see how the vegetation completely envelops the spaces where the water has receded. (Flood water is indicated by light blue, and vegetation is indicated by light green.)
Satellites are an excellent tool for tracking greening events that are followed by flooding. These events offer opportunities for predictive tools as well as recreation.
8. Alaska’s Chukchi Sea
A Monet painting comes to life as the Chukchi Sea swirls with microscopic marine algae.
This image was captured off the Alaskan coast by OLI on Landsat 8 on Jun. 18, 2018. After the Arctic sea ice breaks up each spring, the nutrient-rich Bering Sea water mixes with the nutrient-poor Alaskan coastal water. Each type of water brings with it a different type of phytoplankton and the surface waters have just enough light for the algae to populate and flourish. The result is these mesmerizing patterns of turquoise and green.
This image represents one piece of much larger, incredibly complex ecosystem. While one would not normally associate the breaking up of sea ice with phytoplankton blooms, it is an intricate process of the phytoplankton life cycle. The size of the blooms have varied greatly from year to year, and experts are unsure why. Images like these can help scientists track the development of these blooms and link it to other environmental changes.
7. Hawaii’s Kilauea
Sometimes fresh lava is best viewed in infrared.
This false-color image of Kilauea, captured by OLI on Landsat 8 on May 23, 2018, shows the infrared signal emitted by lava flowing toward the sea. The purple areas surrounding the glowing lava are clouds lit from below, indicating that this image was taken through a break in the clouds.
The Puʻu ʻŌʻō Kupaianaha eruption has been continuously spewing red-hot lava since 1983, making it the longest eruption at Kilauea in recorded history. However, new fissures opened up this year that forced many to evacuate the area. Hawaii’s largest lake evaporated in hours and hundreds of homes were destroyed in Vacationland and Kapoho.
Imagery, seismometers and ground-based instruments were used to track the underground movement of magma. Infrared imagery can be incredibly helpful in disasters like this when you to view data that cannot be observed with the naked eye.
6. California’s Woolsey Burn Scar
Nothing quite encapsulates the destruction of a wildfire like a photo from outer space.
This image of the Woolsey Fire aftermath in Southern California was captured on Nov. 18, 2018 by the Advanced Spaceborned Thermal Emission and Reflection Radiometer (ASTER) on the Terra satellite. This false-color infrared image has been enhanced to clearly show the burned vegetation (indicated by brown) and the vegetation that survived unscathed (indicated by green).
The Woolsey Fire clearly left its mark, with almost 152 square miles (394 square km) and 88% of the Santa Monica Mountains National Recreation Area badly burned. Images like this one can assist fire managers in the area plan for recovery.
5. Bangladesh’s Padma River
As the years go by, the Padma River grows and shrinks, twists and turns. It never has a fixed shape, and as a result, thousands of people must regularly adapt to the constant changes in the river’s 75-mile (130-km) shoreline.
This image captured on Jan. 20, 2018 by OLI on Landsat 8 depicts one of the major rivers of Bangladesh. For thirty years, scientists have been tracking the erosion of the river with satellite imagery. Combinations of shortwave infrared, near infrared, and visible light are used to detect differences year-to-year in width, depth, and shape of the river. Sometimes the river splits off, but then rejoins again later. These patterns are created by the river carrying and depositing sediment, shaping the curves of the path of water.
Monitoring the Padma River is going to become especially important as a new bridge development project advances in the Char Janajat area. Although the bridge will most certainly help shorten travel times for citizens, nobody is quite sure how the river erosion might affect the construction and vice versa.
4. Alaska’s Yakutat Glacier
It’s hard to believe that Harlequin Lake was once all dry land — but it only started to form once Yakutat Glacier started melting. The lake appeared at the beginning of the twentieth century, and has been growing rapidly ever since.
In this hauntingly beautiful image, captured on Sep. 21 2018 by OLI on Landsat 8, the effect of climate change is apparent — especially when compared to earlier images of the region.
Unless the climate warming starts to reverse very soon — which scientists consider very unlikely — Yakutat could be gone as soon as 2070.
3. South Africa’s Theewaterskloof
Cape Town is a seaside city planted on the tip of South Africa. It’s a city known for its beaches and biodiversity — it also almost became known as the first major city to officially run out of water.
This image of Cape Town’s largest reservoir — Theewaterskloof — was acquired on Jul. 9th, 2018 by OLI on Landsat 8. By the time this photo was taken, the city’s main reservoirs stood at 55%. This was a huge increase from where it stood just six months earlier: just 13%.
The severe water shortage in the region started in 2015, only to become more threatening after three successive and unusually dry years. The entire city was preparing for Day Zero — the day the tap water would be shut off.
Despite forecasts that Day Zero would arrive in April, a combination of heavier rains and local conservation efforts restored the majority of the reservoir.
2. Aerosol Earth
Aerosols are all around us. From the smoke from a fire, to the dust in the wind to the salt in sea spray — these solid particles and liquid droplets are always swirling in our atmosphere, oftentimes unseen.
The Goddard Earth Observing System Forward Processing (GEOS FP) model uses mathematical equations to model what is happening in our atmosphere. The inputs for its equations — temperature, moisture, wind, etc. — come from our satellites and ground sensors.
This visualization was compiled on Aug. 24, 2018 — obviously a busy day for aerosols in our atmosphere. Swirls of sea salt (indicated by blue) reveal typhoons Soulik and Cimaron heading straight towards South Korea and Japan. A haze of black carbon (indicated by red) suffuse from agricultural burning in Africa and large wildfires in North America. And clouds of dust (indicated by purple) float off the Sahara desert.
1. Camp Fire
With nearly a hundred fatalities, hundreds of thousands of acres burned and billions of dollars of damage, the world watched in horror as Camp Fire grew to become the most destructive California wildfire in recorded history.
This image was captured on Nov. 8, 2018 by OLI on Landsat 8 on the same day Camp Fire ignited. It consolidates both visible light and shortwave-infrared light in order to highlight the active fire. Strong winds and dry conditions literally fanned the flames and spread this wildfire like a rash.
This image has not only become the iconic portrait for Camp Fire, it is also sobering representation of how quickly a fire can grow out of control in a short amount of time. Even from space, you can almost smell the massive plumes of smoke and feel the heat of the fires.
Whether you realize it or not, our Earth satellite missions are collecting data everyday in order to monitor environmental changes and prepare for natural disasters. If your interest is piqued by this list, head over to the Earth Observatory. The Earth Observatory updates daily with fresh, new content — brought to you by none other than our eyes in the sky.
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10 Things: How to Photograph a Meteor Shower
Taking photographs of a meteor shower can be an exercise in patience as meteors streak across the sky quickly and unannounced, but with these tips – and some good fortune – you might be rewarded with a great photo.
These tips are meant for a DSLR or mirrorless camera, but some point-and-shoot cameras with manual controls could be used as well.
1. The Photo Op: Perseids Meteors
The Perseids are dusty remnants of comet 109P/Swift-Tuttle.
Earth passes through the comet’s invisible, multi-billion mile trail of tiny debris each year around August, creating a meteor shower of so-called “shooting stars” as the particles are vaporized in our atmosphere.
Perseid meteors already are streaking across the sky. This year's shower peaks on a moonless summer night -from 4 pm on the 12th until 4 am on the 13th Eastern Daylight Time.
Read more on the Perseids ›
2. Get away from city lights and find a place with dark skies.
In this 30 second exposure, a meteor streaks across the sky in Spruce Knob, West Virginia, during the 2016 Perseids meteor shower. Credit: NASA/Bill Ingalls
Too much light and it will be hard for your eyes to see fainter meteors, plus your image will get flooded with the glow of light. Turning down the brightness of the camera’s LCD screen will help keep your eyes adjusted to the dark. The peak of the 2018 Perseid meteor shower occurs just after the new moon, meaning a thin crescent will set long before the best viewing hours, leaving hopeful sky watchers with a moonlight-free sky!
3. Use a tripod.
In this ten-second exposure, a meteor streaks across the sky above Washington, DC during the 2015 Perseids meteor shower, Credit: NASA/Joel Kowsky
Meteor photography requires long exposures, and even the steadiest of hands can’t hold a camera still enough for a clear shot. Heavier tripods help reduce shaking caused by wind and footsteps, but even a lightweight tripod will do. You can always place sandbags against the feet of the tripod to add weight and stability. If you don’t have a tripod, you might be able to prop your camera on or up against something around you, but be sure to secure your camera.
4. Use a wide-angle lens.
In this 30 second exposure taken with a circular fish-eye lens, a meteor streaks across the sky during the 2016 Perseids meteor shower as a photographer wipes moisture from the camera lens Friday, August 12, 2016 in Spruce Knob, West Virginia. Credit: NASA/Bill Ingalls
A wide-angle lens will capture more of the sky and give you a greater chance of capturing a meteor in your shot, while a zoom lens captures a smaller area of the sky. The odds of a meteor streaking past that small patch are lower.
5. Use a shutter release cable or the camera’s built-in timer.
Long exposures are not just for meteors. In this shot taken at Joshua Tree National Park, a hiker's headlamp leaves a trail of light along a twilight path. Credit: National Park Service / Hannah Schwalbe
A tripod does a great job of reducing most of the shaking your camera experiences, but even the act of pressing the shutter button can blur your extended exposure. Using the self-timer gives you several seconds for any shaking from pressing the shutter button to stop before the shutter is released. A shutter release cable (without a self-timer) eliminates the need to touch the camera at all. And if your camera has wifi capabilities, you might be able to activate the shutter from a mobile device.
6. Manually focus your lens.
In this 30 second exposure, a meteor streaks across the sky during the annual Perseids meteor shower Friday, August 12, 2016 in Spruce Knob, West Virginia. Credit: NASA/Bill Ingalls
At night, autofocus will struggle to find something on which to focus. Setting your focus to infinity will get you close, but chances are you’ll have to take some test images and do some fine tuning. With your camera on a tripod, take a test image lasting a few seconds, then use the camera’s screen to review the image. Zoom in to a star to see how sharp your focus is. If the stars look like fuzzy blobs, make tiny adjustments to the focus and take another test image.
Repeat until you are happy with the result.
If your camera has a zoomable electronic viewfinder or live view option, you might be able to zoom to a star and focus without having to take a test image.
7. Aim your camera.
The Perseids appear to radiate from the constellation Perseus, visible in the northern sky soon after sunset this time of year.
Even though we don’t know when or where a single meteor will appear, we do know the general area from which they’ll originate.
Meteor showers get their name based on the point in the sky from which they appear to radiate. In the case of the Perseids, during their peak, they appear to come from the direction of the constellation Perseus in the northern sky.
8. Calculate your exposure time.
In this 20-second exposure, a meteor lights up the sky over the top of a mountain ridge near Park City, Utah. Even though this image was captured during the annual Perseid meteor shower, this "shooting star" is probably not one of the Perseid meteors, which originate from material left behind by Comet Swift-Tuttle. Instead, it's likely one of the many bits of rock and dust that randomly fall into the atmosphere on any given night. Credit: NASA/Bill Dunford
As Earth rotates, the stars in the sky appear to move, and if your shutter is open long enough, you might capture some of that movement. If you want to avoid apparent star movement, you can follow the 500 Rule. Take 500 and divide it by the length in millimeters of your lens. The resulting number is the length of time in seconds that you can keep your shutter open before seeing star trails. For example, if you’re using a 20 mm lens, 25 seconds (500 divided by 20) is the longest you can set your exposure time before star trails start to show up in your images.
9. Experiment!
In this 30 second exposure photo, hikers find their way to the top of Spruce Knob in West Virginia to view the annual Perseids meteor shower, Friday, August 12, 2016. Credit: NASA/Bill Ingalls
Once you know the maximum exposure time, you can set your shutter priority to that length and let the camera calculate other settings for your first image. Depending on how the image turns out, you can manually adjust aperture (set it to a lower number if the image is too dark) and ISO (set it to a higher number if the image is too dark) to improve your next images. Changing only one setting at a time will give you a better understanding of how those changes affect your image.
10. Enjoy the show.
The crew of the International Space Station captured this Perseid meteor falling to Earth over China in 2011. Credit: NASA
With your camera settings adjusted, capturing that perfect photo is just a matter of time and luck. The highest rate of meteors visible per hour is in the hours after midnight and before dawn. Set up your camera next to a lounge chair or a blanket to witness the wonder of a meteor shower for yourself – and, with any luck, you’ll take home some envy-inducing shots, too!
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We Need Your Help to Find STEVE
Glowing in mostly purple and green colors, a newly discovered celestial phenomenon is sparking the interest of scientists, photographers and astronauts. The display was initially discovered by a group of citizen scientists who took pictures of the unusual lights and playfully named them "Steve."
When scientists got involved and learned more about these purples and greens, they wanted to keep the name as an homage to its initial name and citizen science discoverers. Now it is STEVE, short for Strong Thermal Emission Velocity Enhancement.
Credit: ©Megan Hoffman
STEVE occurs closer to the equator than where most aurora appear – for example, Southern Canada – in areas known as the sub-auroral zone. Because auroral activity in this zone is not well researched, studying STEVE will help scientists learn about the chemical and physical processes going on there. This helps us paint a better picture of how Earth's magnetic fields function and interact with charged particles in space. Ultimately, scientists can use this information to better understand the space weather near Earth, which can interfere with satellites and communications signals.
Want to become a citizen scientist and help us learn more about STEVE? You can submit your photos to a citizen science project called Aurorasaurus, funded by NASA and the National Science Foundation. Aurorasaurus tracks appearances of auroras – and now STEVE – around the world through reports and photographs submitted via a mobile app and on aurorasaurus.org.
Here are six tips from what we have learned so far to help you spot STEVE:
1. STEVE is a very narrow arc, aligned East-West, and extends for hundreds or thousands of miles.
Credit: ©Megan Hoffman
2. STEVE mostly emits light in purple hues. Sometimes the phenomenon is accompanied by a short-lived, rapidly evolving green picket fence structure (example below).
Credit: ©Megan Hoffman
3. STEVE can last 20 minutes to an hour.
4. STEVE appears closer to the equator than where normal – often green – auroras appear. It appears approximately 5-10° further south in the Northern hemisphere. This means it could appear overhead at latitudes similar to Calgary, Canada. The phenomenon has been reported from the United Kingdom, Canada, Alaska, northern US states, and New Zealand.
5. STEVE has only been spotted so far in the presence of an aurora (but auroras often occur without STEVE). Scientists are investigating to learn more about how the two phenomena are connected.
6. STEVE may only appear in certain seasons. It was not observed from October 2016 to February 2017. It also was not seen from October 2017 to February 2018.
Credit: ©Megan Hoffman
STEVE (and aurora) sightings can be reported at www.aurorasaurus.org or with the Aurorasaurus free mobile apps on Android and iOS. Anyone can sign up, receive alerts, and submit reports for free.
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Subtle Lunar Eclipse
Today’s (Feb. 10) lunar activity comes in the form of a penumbral eclipse. What does that mean and how does this type differ from a total eclipse? Let’s take a look:
First off, what is a penumbra? During a lunar eclipse, two shadows are cast by the Earth. The first is called the umbra (UM bruh). This shadow gets smaller as it goes away from the Earth. It is the dark center of the eclipse shadow where the moon is completely in the shadow of the Earth.
The second shadow is called the penumbra (pe NUM bruh). The penumbra gets larger as it goes away from the Earth. The penumbra is the weak or pale part of the shadow. This occurs because the Earth is covering a portion of the sun.
Penumbral eclipses occur when only the outer shadow (the penumbra) of Earth falls on the moon’s surface. This type of eclipse is much more difficult to observe than total eclipses or when a portion of the moon passes into the umbra. That said, if you’re very observant, you may notice a dark shadow on the moon during mid-eclipse on Friday evening. You may not notice anything at all. It’s likely the moon will just look at little bit darker than normal…like this:
Earth’s penumbral shadow forms a diverging cone that expands into space in the opposite direction of the sun. From within this zone, Earth blocks part but not the entire disk of the sun. Thus, some fraction of the sun’s direct rays continues to reach the most deeply eclipsed parts of the moon during a penumbral eclipse.
For most of North America, the penumbral eclipse will begin at moonrise (sunset) on Friday, Feb. 10 and will be obscured by evening light. Here’s a guide of when to look up:
Fun fact: Aristotle (384 – 322 BCE) first proved that Earth was round using the curved umbral shadow seen at partial eclipses. In comparing observations of several eclipses, he noted that Earth’s shadow was round no matter where the eclipse took place. Aristotle correctly reasoned that only a sphere casts a round shadow from every angle.
To learn more about lunar eclipses, visit: https://svs.gsfc.nasa.gov/11828
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What’s Up for October 2016?
What’s Up for October? Moon phases, Astronomy Day, meteors and Saturn!
The new moon phase starts the month on October 1. Of course, the new moon isn't visible, because it's between Earth and the sun, and the unlit side is facing Earth.
Night by night the slender crescent gets bigger and higher in the sky and easier to see just after sunset. On the 3rd and 4th, the moon will pass just above Venus!
A week later on the 9th the moon has traveled through one quarter of its 29-day orbit around Earth, and we see the first quarter phase. Also look for Mars just below the moon.
Join us in celebrating International Observe the Moon Night Saturday, October 8th, with your local astronomy club or science center. Conveniently, the 8th is also Fall Astronomy Day, celebrated internationally by astronomy clubs since 1973.
One week later on the 16th the moon reaches opposition, or the full moon phase, when the moon and the sun are on opposite sides of Earth. And the sun completely illuminates the moon as seen from Earth.
During this phase, the moon rises in the east just as the sun is setting in the west. Overnight, the moon crosses the sky and sets at dawn.
A week later, on the 22nd of October, the last quarter moon rises at midnight. Later, the pretty and bright Beehive Cluster will be visible near the moon until dawn.
To wrap up the month, 29 days after the last new moon we start the lunar cycle all over again with another new moon phase on October 30th. Will you be able to spot the one-day old moon on Halloween? It will be a challenge!
There are three meteor showers in October--the Draconids, the Taurids and the Orionids. Try for the Draconids on October 8th.
See the Taurids on October 10th.
The Orionids will be marred by the full moon on the 21st, but all three meteor showers will offer some possible bright meteors.
Finally, you’ll have an especially pretty view of Saturn, when it forms a straight line with Venus and the red star Antares on the 27th.
You can catch up on NASA's lunar mission, the Lunar Reconnaissance Orbiter, the Cassini Mission to Saturn and all of our missions at www.nasa.gov.
Watch the full October “What’s Up" video for more:
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Constellations and the Calendar
Did you recently hear that NASA changed the zodiac signs? Nope, we definitely didn’t…
…Here at NASA, we study astronomy, not astrology. We didn’t change any zodiac signs, we just did the math. Here are the details:
First Things First: Astrology is not Astronomy…
Astronomy is the scientific study of everything in outer space. Astronomers and other scientists know that stars many light-years away have no effect on the ordinary activities of humans on Earth.
Astrology, meanwhile, is something else. It’s the belief that the positions of stars and planets can influence human events. It’s not considered a science.
Some curious symbols ring the outside of the Star Finder. These symbols stand for some of the constellations in the zodiac. What is the zodiac and what is special about these constellations?
Imagine a straight line drawn from Earth though the sun and out into space way beyond our solar system where the stars are. Then, picture Earth following its orbit around the sun. This imaginary line would rotate, pointing to different stars throughout one complete trip around the sun – or, one year. All the stars that lie close to the imaginary flat disk swept out by this imaginary line are said to be in the zodiac.
The constellations in the zodiac are simply the constellations that this imaginary straight line points to in its year-long journey.
What are Constellations?
A constellation is group of stars like a dot-to-dot puzzle. If you join the dots—stars, that is—and use lots of imagination, the picture would look like an object, animal, or person. For example, Orion is a group of stars that the Greeks thought looked like a giant hunter with a sword attached to his belt. Other than making a pattern in Earth’s sky, these stars may not be related at all.
Even the closest star is almost unimaginably far away. Because they are so far away, the shapes and positions of the constellations in Earth’s sky change very, very slowly. During one human lifetime, they change hardly at all.
A Long History of Looking to the Stars
The Babylonians lived over 3,000 years ago. They divided the zodiac into 12 equal parts – like cutting a pizza into 12 equal slices. They picked 12 constellations in the zodiac, one for each of the 12 “slices.” So, as Earth orbits the sun, the sun would appear to pass through each of the 12 parts of the zodiac. Since the Babylonians already had a 12-month calendar (based on the phases of the moon), each month got a slice of the zodiac all to itself.
But even according to the Babylonians’ own ancient stories, there were 13 constellations in the zodiac. So they picked one, Ophiuchus, to leave out. Even then, some of the chosen 12 didn’t fit neatly into their assigned slice of the pie and crossed over into the next one.
When the Babylonians first invented the 12 signs of zodiac, a birthday between about July 23 and August 22 meant being born under the constellation Leo. Now, 3,000 years later, the sky has shifted because Earth’s axis (North Pole) doesn’t point in quite the same direction.
The constellations are different sizes and shapes, so the sun spends different lengths of time lined up with each one. The line from Earth through the sun points to Virgo for 45 days, but it points to Scorpius for only 7 days. To make a tidy match with their 12-month calendar, the Babylonians ignored the fact that the sun actually moves through 13 constellations, not 12. Then they assigned each of those 12 constellations equal amounts of time.
So, we didn’t change any zodiac signs…we just did the math.
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What’s Up for July 2016?
What's Up for July? Use Saturn as your guide to a tour of the summer Milky Way.
Saturn continues to dazzle this month. Its wide rings and golden color provide a nice contrast to nearby Mars and Antares. Below Saturn lies the constellation Scorpius, which really does look like a scorpion!
Through binoculars or telescopes you'll be able to spot two pretty star clusters: a compact (or globular) cluster, M-4, and an open cluster, M-7. M-7 is known as Ptolemy's cluster. It was observed and cataloged by Greek-Egyptian astronomer Ptolemy in the first century.
Climbing north, you'll be able to spot the teapot shape which forms part of the constellation Sagittarius. The center of the Milky Way is easy to see. It looks like bright steam rising from the teapot's spout.
With difficulty, a good star chart and a medium-sized telescope you can locate faint Pluto in the "teaspoon" adjacent to the teapot.
A binocular tour of this center core of the Milky Way reveals many beautiful summer sky objects. We first encounter the Eagle Nebula, M-16. Part of this nebula is featured in the famous and beautiful "Pillars of Creation" images taken by our Hubble Space Telescope.
You'll have to stay up later to see the northern Milky Way constellations, which are better placed for viewing later in the summer and fall. Cygnus the swan features the prettiest supernova remnant in the entire sky, the Veil Nebula. It's too big to fit in one eyepiece view, but luckily there are three sections of it.
Look between Aquila and Cygnus to find three tiny constellations: Delphinus the dolphin, Vulpecula the fox and Lyra the lyre (or harp). M-57, the Ring Nebula, is the remains from a shell of ionized gas expelled by a red giant star into the surrounding interstellar medium. It's pretty, too! Look in Vulpecula for the Dumbbell, another planetary nebula.
We'll end our summer tour with Lacerta the lizard and Draco the Dragon. Lacerta is home to a star with an extrasolar planet in its orbit, and Draco, facing away from the center of our Milky Way, is a treasure trove of distant galaxies to catch in your telescope.
Watch the full What’s Up for July 2016 video HERE.
You can catch up on current missions and space telescopes studying our Milky Way and beyond at www.nasa.gov.
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What’s Up for June 2016?
What's Up for June? Saturn at its best! Plus, good views of Mars, Jupiter and Jupiter's moons continue from dusk to dawn.
You don't have to stay up late to see Jupiter, Mars and Saturn this month, because they're all visible soon after sunset. Jupiter is the brightest of the three, visible in the western sky all evening.
The four Galilean moons are easily visible in binoculars or telescopes. If you think you're seeing 5 moons on June 10th, you're not. One of them is a distant star in the constellation Leo.
For telescope viewers, the time near Mars' closest approach to Earth, May 30th this year, is the best time to try to see the two moons of Mars: Phobos and Deimos. It takes patience, very steady skies and good charts! Mars is still large and bright in early June, but it fades as speedy Earth, in its shorter orbit around the sun, passes it.
Saturn has been close to Mars recently. This month Saturn reaches opposition, when Saturn, Earth and the sun are in a straight line with Earth in the middle, providing the best and closest views of the ringed beauty and several of its moons. You'll be able to make out cloud bands on Saturn, in delicate shades of cream and butterscotch. They're fainter than the bands of Jupiter. Through a telescope you'll see Saturn's rings tilted about as wide as they get: 26 degrees.
You'll also have a ring-side view of the Cassini division, discovered by Giovanni Domenico Cassini, namesake of our Cassini spacecraft, orbiting Saturn since 2004 and continuing through September 2017. When you look at Saturn through a telescope, you can't help but see several of its 4 brightest moons, and maybe more. If you just see one, that's Titan, 50% larger than our own moon. A telescope can also reveal more moons, like Saturn's two-colored moon Iapetus. It takes 3 months to orbit Saturn, and it's fairly easy to see.
There's a bright comet visible this month, Comet PanSTARRS. It's best seen from the southern hemisphere, but it's also visible from the U.S. low in the morning sky. Comet PanSTARRS can be seen through a telescope near the beautiful Helix Nebula on June 4, but it is visible all month.
Watch the full June “What’s Up” video for more: https://youtu.be/M7RtIa9zBYA
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What’s Up for March 2016?
In March, Jupiter, it’s moons and moon shadows will all be visible in the sky. Find out when and where to look up:
Jupiter dominates the evening sky this month, rising at sunset and setting at dawn. On March 8, Jupiter reaches what is called “opposition”. Imagine that Jupiter and the sun are at opposite ends of a straight line, with the Earth in between. This brings Jupiter its closest to Earth, so it shines brighter and appears larger in telescopes.
On the nights of March 14 – 15, March 21 – 22 and March 29, two of Jupiter’s moons will cross the planet’s disk.
When the planet is at opposition and the sun shines on Jupiter’s moons, we can see the moon’s shadow crossing the planet. There are actually 11 of these double shadow transits in March!
The next six months will be awesome times for you to image Jupiter when it’s highest in the sky; near midnight now, and a little earlier each night through the late summer.
Even through the smallest telescopes or binoculars, you should be able to see the two prominent belts on each side of Jupiter’s equator made up of the four Galilean moons: Io, Europa Ganymede and Calisto. If you have a good enough view, you may even see Jupiter’s Red Spot!
Our Juno spacecraft will arrive at Jupiter on July 4th of this year and will go into orbit around the giant planet. Right now, the Juno mission science team is actively seeking amateur and professional images of the planet. These images are uploaded to a Juno website, and the public is invited to discuss points of interest in Jupiter’s atmosphere.
Locations will later be voted on and the favorites will be targets for JunoCam, the spacecraft’s imaging camera. Once JunoCam has taken the images, they’ll be posted online. Imaging participants can then process these raw mission images and re-upload them for others to view.
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What’s Up for October?
This month is filled with exciting celestial sights. Here are 10 targets you can view this month:
10. Unusual Sunset
During a sunset, our thick atmosphere absorbs most colors of sunlight, but red light is absorbed the least. Rarely, green flashes can be seen just above the sun’s edge. As the last sliver of the disk disappears below the horizon, be sure to watch its color.
9. Belt of Venus
Just after sunset, turn around and face east. A dark shadow will move up from the horizon and gradually cover the pinkish sky. This is caused from the Earth itself blocking the sunlight and is called the Earth Shadow or the Belt of Venus.
8. Crepuscular Rays
Also just after sunset, or before dawn, you may see rays of sunlight spread like a fan. These are called crepuscular rays and are formed when sunlight streams through gaps in the clouds or mountains.
7. Aurora Borealis
The northern lights, also known as the aurora borealis, are caused by collisions between gaseous particles in Earth’s atmosphere and charged particles released from the sun. The color of the lights can changed depending on the type of gas being struck by particles of solar wind. You can find out when and where to expect aurorae at the Space Weather Prediction Center.
6. Andromeda Galaxy
Did you now that The Andromeda Galaxy is one of the few you can actually see with your naked eye? In October, look nearly overhead after sunset to see it! This galaxy is more than twice the apparent width of the moon.
5. Moon Features
Nights in mid-October are excellent for viewing the features on the moon. Areas like the Sea of Tranquility and the site of the 1969 Apollo 11 landing will be visible.
4. A Comet
This month, the European Space Agency’s Rosetta mission target, a comet with a complicated name (Comet 67P Churyumov-Gerasimenko), is still bright enough for experienced astronomers to pick out in a dark sky. On October 9, you may be able to spot it in the east near the crescent moon and Venus.
3. Meteor Showers
There are multiple meteor showers this month. On the 9th: watch the faint, slow-moving Draconids. On the 10th: catch the slow, super-bright Taurids. And on the 21st: don’t’ miss the swift and bright Orionids from the dust of Comet Halley.
2. Three Close Planets
On October 28, you’ll find a tight grouping of Jupiter, Venus and Mars in the eastern sky before sunrise.
1. Zodiacal Light
The Zodiacal light is a faint triangular glow that can be seen from a dark sky after sunset or before sunrise. What you’re seeing is sunlight reflecting off dust grains that circle the sun in the inner solar system. These dust grains travel in the same plane as the moon and planets as they journey across our sky.
For more stargazing tools visit: Star Tool Box
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NASA Astronaut Scott Kelly shared this incredible video tonight, August 11, showing "our galactic home" with the stars of the Milky Way. Kelly is living and working off the Earth, for the Earth aboard the station for a yearlong mission. Traveling the world more than 220 miles above the Earth, and at 17,500 mph, he circumnavigates the globe more than a dozen times a day conducting research about how the body adapts and changes to living in space for a long duration.
Video credit: NASA