STEREO | What's New /news.xml STEREO/EPO News akpatel1@lssp-mail.gsfc.gov /img/stereo3.gif STEREO - Solar Terrestrial Relations Observatory / Comet 3I / ATLAS STEREO-A observed interstellar comet 3I/ATLAS from Sept. 11 to Oct. 2. STEREO is part of a fleet of NASA spacecraft observing this comet, together providing more information about its size, physical properties, and chemical makeup.

]]> Mercury Transit On April 7th, 2025, the planet Mercury passed between the Sun and the STEREO Ahead spacecraft, casting a shadow onto the telescopes on board. This planetary transit was not visible from Earth. A movie showing the planetfs motion as seen by the EUVI telescope can be seen here.

]]> STEREO Science Stories STEREO is now posting summaries of select papers written using STEREO data. These are written on a level for general scientists. Interested in how STEREO data is used? Take a look at: https://stereo-ssc.nascom.nasa.gov/publications/nuggets.shtml

]]> Side View of Solar Storms May 9-14, 2024 STEREO-A had a unique side view of last weekend's solar storms, observing multiple CME fronts as they headed towards Earth. STEREO-A also gave a heads up on the strength of the storms when they hit the spacecraft over two hours before they reached Earth.

]]> STEREO-A One of Multiple Spacecraft Telling the Story of a Giant Solar Storm https://science.nasa.gov/science-research/heliophysics/multiple-spacecraft-tell-the-story-of-one-giant-solar-storm/ April 17, 2021, was a day like any other day on the Sun, until a brilliant flash erupted and an enormous cloud of solar material billowed away from our star. Such outbursts from the Sun are not unusual, but this one was unusually widespread, hurling high-speed protons and electrons at velocities nearing the speed of light and striking several spacecraft across the inner solar system. A science team has now put together data from multiple spacecraft, including STEREO-A, to understand the sources of the solar energetic particles (SEPs) hurled Earthward by the Sun.

]]> New STEREO 3D movies /gallery/3dimages.shtml When the STEREO mission was first launched in 2006, with the Ahead and Behind spacecraft each put into their own orbits about the Sun, they soon reached a point where the views from the two spacecraft were ideally situated to make 3D stereoscopic images. As the spacecraft continued to separate, the distance became too large to make such stereoscopic images, but the data continued to be useful to scientists to derive information about the 3D structures of solar features. We unfortunately lost control of STEREO Behind in 2014, just before it was about to pass behind the Sun, but Ahead continued in its orbit to pass by Earth again in 2023. While we could no longer combine images from the two STEREO spacecraft, we were able to use equivalent images from the NASA Solar Dynamics Observatory to once again make stereoscopic movies, with the added advantage of a much more active Sun. You can find these movies in our 3D gallery.

]]> STEREO sees Comet Nishimura https://www.space.com/comet-nishimura-photobombs-sun-spacecraft The recently discovered Comet Nishimura, which has been getting a lot of attention lately, is now visible in STEREO's inner Heliospheric Imager (HI-1) field-of-view. The comet first appeared in the STEREO images on September 17, just a few hours before it made its closest approach to the Sun. At first, the comet was only visible in the low resolution and heavily compressed space weather beacon images that come down from the spacecraft in real-time, but it is now starting to appear in the full science quality images that some available a few days later, as seen in this movie.

]]> Ham radio operator captures STEREO rotating https://spaceweather.com/archive.php?day=15&month=08&year=2023&view=view After 17 years, the STEREO Ahead spacecraft is passing close to Earth again, with closest approach on August 17. As it passes by, the spacecraft has to rotate to keep the high gain antenna pointed at Earth so that communications aren't interrupted. As described in this story on spaceweather.com, ham radio operator Scott Tilly (VE7TIL) has been capturing space weather beacon images from the spacecraft, and sees the effect the rotation has on STEREO images. It makes it look like the Sun is spinning.

]]> After Seventeen Years, A Spacecraft Makes Its First Visit Home http://www.nasa.gov/feature/goddard/2023/sun/after-seventeen-years-a-spacecraft-makes-its-first-visit-home On Aug. 12, 2023, NASA's STEREO-A spacecraft will pass between the Sun and Earth, marking the first Earth flyby of the nearly 17-year-old mission. The visit home brings a special chance for the spacecraft to collaborate with NASA missions near Earth and reveal new insights into our closest star.

]]> Halo CME captured by STEREO at high cadence /~thompson/cor2_halo_20270724.html On July 24, 2023, the SECCHI COR2 telescope aboard the STEREO-A spacecraft observed a large coronal mass ejection that completely surrounded the Sun. Such events are know as "halo" CMEs. CMEs appear as haloes either when they are heading directly toward the observer or directly away; in this case the CME happened on the far side of the Sun. STEREO-A is currently very close to Earth, so that means that the CME is also heading away from Earth. These images were made when the STEREO-A spacecraft was in a special high telemetry campaign, and the COR2 images were being taken at a much higher cadence than usual, which will allow this CME to be studied in great detail.

]]> Amateur radio astronomers pick up signal from STEREO-A https://skyriddles.wordpress.com/2023/07/03/stereo-a-comes-home/ After leaving Earth to fly around the Sun 17 years ago, the STEREO Ahead spacecraft has come back around and will fly by Earth this summer, with closest approach on August 17th. STEREO Ahead is so close to Earth now that some radio astronomers have been able to hear its radio signal, and even to decode part of its beacon telemetry, as described in this article

]]> STEREO contributes to study of study of Betelgeuse eruption https://www.nasa.gov/feature/goddard/2022/hubble-sees-red-supergiant-star-betelgeuse-slowly-recovering-after-blowing-its-top The STEREO-A spacecraft played an important role in a recent study using data from the Hubble Space Telescope and other observatories that showed that the star Betelgeuse ejected a substantial part of its visible surface in late 2019. Thanks to STEREO-A's unique position within the solar system, and by rolling the spacecraft by 180 degrees from its usual orientation, its outer Heliospheric Imager telescope was able to measure Betelgeuse's brightness during a time when the star was too close to the Sun to be observed from Earth. These measurements were critical for monitoring Betelgeuse's unusual behavior during that time.

]]> STEREO Observes large CME /news/cme_20220215_cor2.html STEREO observed a large CME on 2022-02-15 thru 2022-02-16.

]]> Comet Leonard appears in STEREO telescope /news/cometleonard.shtml Over the past couple of days, speculation has grown among astronomers that comet Leonard may be undergoing "outbursts" - rapid changes in brightness corresponding to large and abrupt releases of volatile material.

]]> STEREO's unique view of the new solar cycle. /news/newsolarcycle.shtml The Sun is waking up from the solar minimum and starting to produce coronal mass ejections (CMEs) and flares in greater numbers. Here STEREO images a spectacular CME that blasted off a few days ago from a region that is continuing to produce activity as it comes around the solar limb to face Earth.

]]> Scheduled website outage Starting on June 11 thru June 14, 2021, the building which houses the STEREO data and web servers will undergo critical infrastructure maintenance. This will require the STEREO servers to go offline for that duration. We apologize for any inconvenience this may cause.

]]> STEREO-A, Parker Solar Probe, and Solar Orbiter: Unique Views of the Solar System https://www.nasa.gov/feature/goddard/2021/unique-solar-system-views-from-nasa-sun-studying-missions Though they focus on the star at the center of our solar system, three of NASA's Sun-watching spacecraft have captured unique views of the planets throughout the last several months.

]]> NASA Satellite's Lone View of Betelgeuse Reveals More Strange Behavior https://www.nasa.gov/feature/goddard/2020/nasa-satellite-s-lone-view-of-betelgeuse-reveals-more-strange-behavior For several weeks in summer 2020, NASA's Solar and Terrestrial Relations Observatory, or STEREO, had the solar system's best view of the star Betelgeuse, whose extreme dimming over the past several months has intrigued scientists. STEREO's measurements revealed more unexpected dimming by the star, further adding to the questions around Betelgeuse's recent behavior.

]]> STEREO and Other Observatories Join to Support Latest Parker Solar Probe Pass https://www.nasa.gov/feature/goddard/2020/nasa-parker-solar-probe-teams-up-with-observatories-around-solar-system-for-4th-solar-encounter A broad observing campaign has allowed scientists to assemble a wide array of data to study the Sun and solar wind during Parker Solar Probe's 4th pass close to the Sun.

]]> STEREO-A images comet ATLAS as it swoops by the Sun from May 25 - June 1 https://www.nasa.gov/image-feature/goddard/2020/stereo-watches-comet-atlas-as-solar-orbiter-crosses-its-tail NASA's Solar Terrestrial Relations Observatory, or STEREO-A spacecraft, captured these images of comet ATLAS as it swooped by the Sun from May 25 - June 1. During the observations and outside STEREO's field of view, ESA/NASA's Solar Orbiter spacecraft crossed one of the comet's two tails.

]]> Notice to STEREO data users /curl.shtml Notice to cURL and wget users

]]> Circular wheel shaped reflection in STEREO data explained /artifacts/wheel/ Some people have noticed an odd shape, sort of a cross inside a circle entering the field-of-view of the HI2 telescope on STEREO Ahead around February 20,2020. The answer lies on the exact opposite side of the image.

]]> STEREO Principle Investigators Honored https://eos.org/agu-news/2019-class-of-agu-fellows-announced STEREO is proud to announce that two of its Principle Investigators, Drs. Toni Galvin of PLASTIC and Russ Howard of SECCHI have been selected as Fellows of the American Geophysical Union. A third, Janet Luhmann of IMPACT, has been a Fellow since 1997. Fellows are AGU members whose visionary leadership and scientific excellence have fundamentally advanced research in their respective fields.

]]> Citizen Scientists use STEREO data to study complexity in solar storms https://ras.ac.uk/news-and-press/news/citizen-scientists-discover-cyclical-pattern-complexity-solar-storms Citizen scientists have used STEREO/HI data to have discovered that complexity of solar storms tracks the solar cycle.

]]> A Ring Around the Sun https://www.nasa.gov/feature/goddard/2019/what-scientists-found-after-sifting-through-dust-in-the-solar-system STEREO data reveal an unexpected trail of dust in the orbit of Mercury

]]> New Insights on Comet Tails Are Blowing in the Solar Wind https://www.nasa.gov/feature/goddard/2018/new-insights-on-comet-tails-are-blowing-in-the-solar-wind STEREO data are contributing to a new understanding of comets and how they are affected by the Sun.

]]> Discovering Fine Structure in the Outer Corona https://www.nasa.gov/feature/goddard/2018/discovering-structure-in-the-outer-corona Scientists use special STEREO campaign data and state-of-the-art image processing to reveal the structure of the solar corona as it flows outward to become the solar wind.

]]> 3 NASA Satellites Recreate Solar Eruption in 3-D https://www.nasa.gov/feature/goddard/2018/3-nasa-satellites-recreate-solar-eruption-in-3-d The more solar observatories, the merrier: Scientists have developed new models to see how shocks associated with coronal mass ejections, or CMEs, propagate from the Sun - an effort made possible only by combining data from three NASA satellites to produce a much more robust mapping of a CME than any one could do alone.

]]> Magnetic coil springs accelerate particles on the Sun http://www.mps.mpg.de/Magnetic-coil-springs-accelerate-particles-on-the-Sun In April and July 2014, the Sun emitted three jets of energetic particles into space, that were quite exceptional: the particle flows contained such high amounts of iron and helium-3, a rare variety of helium, as have been observed only few times before. STEREO observations enabled researchers to determine the sources of these energetic particles.

]]> STEREO images show the Sun's Outer Atmosphere is More Complex than Previously Thought https://www.sciencenews.org/article/sun-corona-outer-atmosphere-complex The outer part of the Sun's atmosphere, the corona, looks pretty smooth, but new deep exposures of the outer corona reveal complex structures. This should make for some interesting observations from the upcoming Parker Solar Probe Mission (to be launched in 2018), which will be flying right through these regions.

]]> Return of the Comet: 96P Spotted by ESA, NASA Satellites https://www.nasa.gov/feature/goddard/2017/return-of-the-comet-96p-spotted-by-esa-nasa-satellites Sun-gazing missions SOHO and STEREO watched the return of comet 96P/Machholz when it entered their fields of view between Oct. 25-30. It is extremely rare for comets to be seen simultaneously from two different locations in space, and these are the most comprehensive parallel observations ever taken of this comet.

]]> Comet 96P/Machholz https://sohowww.nascom.nasa.gov/pickoftheweek/old/20oct2017/ The STEREO and SOHO Teams are gearing up for a planned visit by one of our favorite celestial wanderers! The comet 96P/Machholz should be in the STEREO field of view October 26-28. SOHO will be seeing it at the same time, giving us simultaneous views of 96P from two different locations in space!

]]> Calling all Citizen Scientists! https://www.zooniverse.org/projects/shannon-/solar-stormwatch-ii Want to help solar scientists use STEREO data to better understand Coronal Mass Ejections? You can do that, with no previous experience required. The Solar Stormwatch Project is looking for volunteers who want to help analyze these giant solar storms as they move through the solar system. For more info about how to participate check out the Solar Stormwatch web page.

]]> Waves on Sun Give New Insight into Space Weather Forecasting https://www.nasa.gov/feature/goddard/2017/waves-on-sun-give-nasa-new-insight-into-space-weather-forecasting STEREO and SDO observations of the solar poles reveal large scale waves that could help us predict the locations of future solar active regions.

]]> NASA's Fermi Sees Gamma Rays from 'Hidden' Solar Flares with help from STEREO https://www.nasa.gov/feature/goddard/2017/nasas-fermi-sees-gamma-rays-from-hidden-solar-flares An international science team says NASA's Fermi Gamma-ray Space Telescope has observed high-energy light from solar eruptions located on the far side of the sun, which should block direct light from these events. This apparent paradox is providing solar scientists with a unique tool for exploring how charged particles are accelerated to nearly the speed of light and move across the sun during solar flares. Thanks to the STEREO spacecraft, which were monitoring the solar far side when the eruptions occurred, the Fermi events mark the first time scientists have direct imaging of beyond-the-limb solar flares associated with high-energy gamma rays.

]]> SUN 360: Our Solar System's Space Weather Watchdog https://airandspace.si.edu/events/sun-360-our-solar-system%E2%80%99s-space-weather-watchdog Join us for a series of presentations celebrating STEREO and efforts to predict space weather on the 10th anniversary of STEREO's launch, October 25, at 1:00 pm EDT. A panel of scientists including scientist-astronaut John Grunsfeld will discus how monitoring the Sun from widely different angles simultaneously can provide early warnings of explosive events on the Sun. The event will held at the National Air and Space Museum in Washington DC and will also be streamed on line and archived for future viewing.

]]> Images From Sun's Edge Reveal Origins of Solar Wind https://www.nasa.gov/feature/goddard/2016/images-from-sun-s-edge-reveal-origins-of-solar-wind Ever since the 1950s discovery of the solar wind - the constant flow of charged particles from the sun - there's been a stark disconnect between this outpouring and the sun itself. As it approaches Earth, the solar wind is gusty and turbulent. But near the sun where it originates, this wind is structured in distinct rays, much like a child's simple drawing of the sun. The details of the transition from defined rays in the corona, the sun's upper atmosphere, to the solar wind have been, until now, a mystery.

]]> A NASA Satellite Ends the Silent Treatment http://www.nytimes.com/2016/08/30/science/a-nasa-satellite-ends-the-silent-treatment.html?_r=0 NASA has re-established contact with an errant spacecraft. In October 2006, the space agency sent twin satellites into orbit to study the Sun. The satellites follow Earth's orbit around the sun, one ahead of us and one behind: STEREO-A and STEREO-B.

]]> NASA Establishes Contact With STEREO Mission https://www.nasa.gov/feature/goddard/2016/nasa-establishes-contact-with-stereo-mission On Aug. 21, 2016, contact was reestablished with one of NASA's Solar Terrestrial Relations Observatories, known as the STEREO-B spacecraft, after communications were lost on Oct. 1, 2014. Over 22 months, the STEREO team has worked to attempt contact with the spacecraft. Most recently, they have attempted a monthly recovery operation using NASA's Deep Space Network, or DSN, which tracks and communicates with missions throughout space.

]]> Seeing Double: NASA Missions Measure Solar Flare from 2 Spots in Space https://www.nasa.gov/feature/goddard/2016/seeing-double-nasa-missions-measure-solar-flare-from-2-spots-in-space/ Solar flares are intense bursts of light from the sun. They are created when complicated magnetic fields suddenly and explosively rearrange themselves, converting magnetic energy into light through a process called magnetic reconnection at least, that's the theory, because the signatures of this process are hard to detect. But during a December 2013 solar flare, three solar observatories captured the most comprehensive observations of an electromagnetic phenomenon called a current sheet, strengthening the evidence that this understanding of solar flares is correct.

]]> Saving NASA's STEREO-B: The 189-million-mile Road to Recovery https://www.nasa.gov/feature/goddard/saving-nasas-stereo-b-the-189-million-mile-road-to-recovery On Oct. 1, 2014, NASA lost communication with one of two STEREO missions spacecraft, just as the satellite was about to orbit around the other side of the sun. More than a year's worth of silence later, the spacecraft has finally emerged into a region where it can again receive signals -- and scientists have a plan to get it back.

]]> NASA's STEREO-A Resumes Normal Operations https://www.nasa.gov/feature/goddard/nasa-s-stereo-a-resumes-normal-operations On Nov. 9, 2015, NASAs Solar and Terrestrial Relations Observatory Ahead, or STEREO-A, once again began transmitting data at its full rate. For the previous year, STEREO-A was transmitting only a weak signal or occasionally none at all due to its position almost directly behind the sun. Subsequently, as of Nov. 17, STEREO resumed its normal science operations, which includes transmission of lower-resolution real-time data used by scientists to monitor solar events as well as high-definition, but delayed, images of the sun's surface and atmosphere.

]]> Comet Encke: A Solar Windsock Observed by NASA's STEREO https://www.nasa.gov/feature/goddard/comet-encke-a-solar-windsock-observed-by-nasa-s-stereo Much like the flapping of a windsock displays the quick changes in wind's speed and direction, called turbulence, comet tails can be used as probes of the solar wind - the constant flowing stream of material that leaves the sun in all directions. According to new studies of a comet tail observed by STEREO, the vacuum of interplanetary space is filled with turbulence and swirling vortices similar to gusts of wind on Earth. Such turbulence can help explain two of the wind's most curious features: its variable nature and unexpectedly high temperatures.

]]> Blast waves in the Sun's atmosphere http://www.mps.mpg.de/4150791/PM_2015_10_13_Riesige_Wellen_in_der_Sonnenatmosphaere Two teams of researchers led by Nariaki Nitta from the Lockheed Martin Advanced Technology Center in the USA and by Radoslav Buck from the Max Planck Institute for Solar System Research (MPS) in Germany have independently discovered a new solar phenomenon: large-scale waves in the star's atmosphere accompanied by energetic particle emissions rich in helium-3. Helium-3 is a light variety of the inert gas helium. The huge waves may contribute significantly to accelerate the particles into space, the MPS scientists now report in The Astrophysical Journal. Decisive for this discovery were the two spacecraft STEREO A and ACE making it possible to simultaneously observe the Sun from two different directions. In the near future, no such opportunity will arise again.

]]> NASA Cites the Return of the STEREO-A Spacecraft https://www.nasa.gov/feature/goddard/stereo/return-of-the-stereo-a-spacecraft On July 11, 2015 we received our first images in over three months from NASA's Solar TErrestrial RElations Observatory Ahead spacecraft, or STEREO-A. Since March 24, 2015, STEREO-A has been on the far side of the sun, where it has had to operate in safe mode, collecting and saving data from its radio instrument.

The three-month safe mode period was necessary because of the geometry between Earth, the sun, and STEREO-A. STEREO-A orbits the sun as Earth does, but in a slightly smaller and faster orbit. The orbit ensured that over the course of years, Earth and the spacecraft got out of sync, with STEREO-A ending up on the other side of the sun from Earth, where it could show us views of our star that we couldnt see from home. Though the sun only physically blocked STEREO-A from Earths line of sight for a few days, STEREO-A was close enough to the sunfrom our perspective -- that from March 24 until July 8, the sun interfered with STEREO-As data transmission signal, making it impossible to interpret.

]]> STEREO going into "safe mode" on far side of Sun http://secchi.nrl.navy.mil/movies/cor2a_20150128.mov The IMPACT, PLASTIC, and SECCHI instruments on STEREO Ahead were turned off at 16:00 UT on Friday, 20 March 2015 in preparation for superior solar conjunction. On Tuesday, 24 March, also at 16:00 UT, the STEREO Ahead spacecraft will be reset into a "safe mode" that it will remain in for the next several months until normal operations can be resumed again in July.

The term "superior solar conjunction" is the technical phrase which refers to period when one or the other STEREO spacecraft is on the opposite side of the Sun from Earth. For each spacecraft, there is a period when it is so close to the Sun as seen from Earth that the radio interference from the Sun makes it impossible to communicate at all with the spacecraft. For a few days, it will even be physically blocked by the Sun. Without any possibility of communications, the spacecraft will have to be placed into "safe mode" until contact can be reestablished. Before communications are completely cut off, the spacecraft will start slowly rotating about the axis which points at the Sun. This is done to reduce the load on the reaction wheels which keep the spacecraft pointing stabilized. All the science instruments will be turned off, with the sole exception of the radio instrument SWAVES which will stay on to record beacon mode data on the recorder for eventual playback in November 2015. Technical and safety considerations prevent the other instruments from being on during this time.

]]> A Selfie from the Other Side of the Sun. http://secchi.nrl.navy.mil/movies/cor2a_20150128.mov STEREO-A is now on the other side of the Sun, over 290 million km (180 million miles) away (See Where is STEREO? ). Recently, a new planet has appeared in the field of view of it sun-pointed instruments: Earth. You can see Earth and Mercury in this movie from STEREO Ahead's SECCHI Cor2 coronagraph. The location of the Sun (hidden by a disk so we can see its faint outer atmosphere) is shown with the white circle. The horizontal lines through the two planets are due to saturation effects in the detector - the planets are brighter than the solar features the cameras were designed for.

]]> Loss of Contact with STEREO Behind https://stereo-ssc.nascom.nasa.gov/behind_status.shtml Communications with the STEREO Behind spacecraft were interrupted on October 1, 2014 immediately after a planned reset of the spacecraft performed as part of a test of solar conjunction operations. The spacecraft telemetry indicated an anomaly in the guidance and control system, but this is still being evaluated. No further communications have been successful since Oct. 1st. Follow this link for more information.

The STEREO Ahead spacecraft has already successfully tested the transition into and out of solar conjunction operations. Actual solar conjunction operations will take place between March 22 and July 14, 2015. STEREO Ahead continues to operate nominally, and is currently providing our only views of the far side of the sun.

Attempts to reestablish communications with the STEREO Behind spacecraft are ongoing.

Launched in 2006, the STEREO mission achieved its prime science goals within the two-year prime mission, but continues to explore solar and heliospheric activity through the current solar maxmimum and beyond.

]]> STEREO Entering New Stage of Operations https://www.nasa.gov/content/goddard/stereo-entering-new-stage-of-operations/ Since February 2011, the two spacecraft of NASA's STEREO mission have been providing scientists with unprecedented views of the far side of the sun. Placed in orbits that allow their perspective to change over the eight years since their launch in 2006, the satellites are about to enter a new phase of their journey: a time when the bright light and heat of the sun will stand in the way of sending data back to Earth.

]]> NASA MESSENGER and STEREO Measurements Open New Window Into High - Energy Processes on the Sun https://www.nasa.gov/content/goddard/messenger-stereo-measurements-open-new-window-into-high-energy-processes-on-the-sun/ Understanding the sun from afar isn't easy. How do you figure out what powers solar flares - the intense bursts of radiation coming from the release of magnetic energy associated with sunspots when you must rely on observing only the light and particles that make their way to near-Earth's orbit?

]]> NASA's STEREO Maps Much Larger Solar Atmosphere Than Previously Observed https://www.nasa.gov/content/goddard/nasas-stereo-maps-much-larger-solar-atmosphere-than-previously-observed/ Surrounding the sun is a vast atmosphere of solar particles, through which magnetic fields swarm, solar flares erupt, and gigantic columns of material rise, fall and jostle each other around. Now, using observations from NASA's STEREO, scientists have found that this atmosphere, called the corona, is even larger than previously thought.

]]> Panoramic view of particles from the Sun http://www.mps.mpg.de/3530701/PM_2014_05_14_Panoramic_view_of_the_Sun_s_particles Time and again, the sun hurls energetic charged particles into space in violent eruptions. At the same time, a continuous stream of particles, the solar wind, escapes from its surface. Numerous space probes in the Earths vicinity monitor how this matter propagates through space. However, until STEREO this information never showed the whole picture.

]]> The "Perfect" Solar Storm? /news/perfectstorm.shtml On July 22, 2012, a massive cloud of solar material erupted off the sun's right side, zooming out into space and passing one of NASA's two Solar Terrestrial Observatory (STEREO) spacecraft along the way. Scientists clocked this giant cloud, known as a coronal mass ejection, or CME, as traveling over 3000 kilometers per second as it left the Sun.

]]> Four Comets at Once /news/FourComets.shtml Four comets are now visible using STEREO-A's HI2, although you'll have to look very closely to see them all.

]]> MAVEN is on its way https://stereo-ssc.nascom.nasa.gov/cgi-bin/make_where_gif The MAVEN mission is headed for Mars and will be partnering with STEREO on the way. The MAVEN mission includes solar wind sensors which combined with those of STEREO will provide another vantage point so that we can better understand the 3D structure of our complex space environment. In addition, STEREO keeps an eye on space weather throughout the solar system, providing warnings of danger to MAVEN and other spacecraft far from Earth.

You can follow the progress of MAVEN and STEREO with the STEREO orbit tool by checking off MAVEN at the bottom of the page.

]]> STEREO's anticipated observations of Comet ISON https://stereo-ssc.nascom.nasa.gov/comet_ison/ Astronomers are eagerly awaiting the arrival of Comet ISON, which will pass within just 2.7 solar radii from Sun center on November 28, 2013 (U.S. Thanksgiving). Although comets are unpredictable, Comet ISON has the potential to be a major comet. If so, STEREO should have a spectacular view. To assist with planning for this event, a new web page has been put together describing Comet ISON's orbit, and how the comet will be seen by STEREO's telescopes, and those on other solar observatories.

]]> Earth now visible in STEREO Behind's Inner Heliospheric Imager /gallery/item.php?id=stereoimages&iid=197 The STEREO Behind spacecraft has now moved far enough in its orbit for Earth to enter the HI1-B field-of-view. Earth has been visible in the HI2 telescopes since launch, but this is the first time it's been visible in either of the HI1 telescopes, which image areas closer to the Sun. This is happening because the STEREO spacecraft are moving closer to the points in their orbits at which they will be directly opposite Earth on the other side of the Sun.

]]> NASA STEREO Observes One of the Fastest CMEs On Record https://www.nasa.gov/mission_pages/stereo/news/fast-cme.html On July 23, 2012, a massive cloud of solar material erupted off the sun's right side, zooming out into space, passing one of NASA's STEREO spacecraft along the way. Using the STEREO data, scientists at NASA's Goddard Space Flight Center in Greenbelt, Md. clocked this giant cloud, known as a coronal mass ejection, or CME, as traveling between 1,800 and 2,200 miles per second as it left the sun.

]]> Giant sunspot shoots out intense, X-class solar flare http://www.washingtonpost.com/blogs/capital-weather-gang/post/giant-sunspot-shoots-out-intense-x-class-solar-flare/2012/07/12/gJQAKpDtfW_blog.html A massive sunspot region facing Earth - known as 1520 - has unleashed a large solar flare. NOAAs Space Weather Prediction Center says the flare is rated an X1.4. This type of flare is considered strong and can cause a blackout of high frequency radio communication on the sunlit side of Earth for one to two hours.

]]> STEREO B sees NOVA SAGITTARII 2012 http://cometal-comets.blogspot.com/2012/04/stereo-b-sees-nova-sagittarii-2012.html NOVA SAGITTARII 2012 = PNV J17452791-2305213, becomes apparent in STEREO HI1B imager across 20120420-23.

]]> SDO and STEREO Spot Something New On the Sun https://www.nasa.gov/mission_pages/sunearth/news/solar-plumes.html One day in the fall of 2011, Neil Sheeley, a solar scientist at the Naval Research Laboratory in Washington, D.C., did what he always does look through the daily images of the sun from NASA's Solar Dynamics Observatory (SDO).

But on this day he saw something he'd never noticed before: a pattern of cells with bright centers and dark boundaries occurring in the sun's atmosphere, the corona. These cells looked somewhat like a cell pattern that occurs on the sun's surface -- similar to the bubbles that rise to the top of boiling water -- but it was a surprise to find this pattern higher up in the corona, which is normally dominated by bright loops and dark coronal holes.

]]> What is the biggest NASA accomplishment of 2011? https://www.nasa.gov/news/11_YIR_poll.html Twin Solar Spacecraft Take First Complete Image of Far Side of Sun

]]> Triangular shaped object in STEREO data explained /artifacts/triangle/ Some people have noticed a strange triangular or diamond-shape "object" entering the field-of-view of the HI2 telescope on STEREO Behind around December 26, 2011. You can see the feature in question in this movie moving from right-to-left, just above the trapezoidal occulter on the right side of the image, and more clearly in this close-up movie. What is this?

]]> A 360 Degree View of an X-class Flare and A CME https://www.nasa.gov/mission_pages/sunearth/news/News110411-x1.9-cme.html The two STEREO spacecraft now sit on opposite sides of the sun providing a view of the latest solar activity for the entire solar system.

]]> STEREO Mission Celebrates Five Incredible Years of Science https://www.nasa.gov/mission_pages/stereo/news/five-years.html On October 25, 2006 a Delta II rocket launched from Cape Canaveral carrying two nearly identical spacecraft. Each satellite was one half of a mission entitled Solar TErrestrial RElations Observatory (STEREO) and they were destined to do something never done before - see the entire sun simultaneously.

]]> Space Storm Tracked from Sun to Earth https://www.nasa.gov/mission_pages/stereo/news/solarstorm-tracking.html For the first time, a spacecraft far from Earth has turned and watched a solar storm engulf our planet. The movie, released today during a NASA press conference, has galvanized solar physicists, who say it could lead to important advances in space weather forecasting.

]]> Scientists see solar outburst in exquisite detail http://www.ras.org.uk/news-and-press/217-news2011/1953-nam-12-scientists-see-solar-outburst-in-exquisite-detail Combined data from the STEREO and ACE spacecraft are being used to study the structure of a CME in unprecedented detail, showing considerable evolution in the CME's internal structure as it moves from the Sun to Earth.

]]> STEREO turns its steady gaze on variable stars /news/VariableStars.shtml Researchers have discovered 122 new eclipsing binary stars and observed hundreds more variable stars in an innovative survey using NASA's two STEREO solar satellites.

]]> STEREO sees the Entire Sun https://www.nasa.gov/mission_pages/stereo/news/entire-sun.html On February 6, 2011, NASA released the first ever images of the entire Sun, using a combination of STEREO images together with data from the Solar Dynamics Observatory. This never before seen view was made possible by STEREO's unique viewing geometry.

]]> Coming Soon - The Entire Sun http://www.youtube.com/watch?v=Z9ITDs-n7gQ For the past 4 years, the two STEREO spacecraft have been moving away from the Earth and gaining a more complete picture of the sun. On February 6, 2011, NASA will reveal the first ever images of the entire sun and discuss the importance of seeing all of our dynamic star.

]]> PUBLIC SPOT SIGNIFICANT SOLAR STORM HEADING FOR EARTH THIS WEEK IN FIRST FOR ONLINE SOLAR STORMWATCH PROJECT http://www.nmm.ac.uk/about/press/public-spot-significant-solar-storm For the first time scientists have used data analysed by the public to make a real-time prediction of a solar storm that should reach Earth on Monday 13 December, thanks to the Solar Stormwatch web project.

The initiative, launched in February by the Royal Observatory, Greenwich (ROG), in partnership with the STFC Rutherford Appleton Laboratory and the Zooniverse citizen science project, makes it possible for anyone with an internet connection to get involved in the latest solar research by helping to spot and track storms as they erupt from the surface of the Sun. These collective measurements enable scientists to forecast the arrival of storms far enough in advance to issue effective pre-emptive warnings for the first time.

The Sun is much more dynamic than it appears to the naked eye. Intense magnetic fields churn and pummel the Suns atmosphere and they store enormous amounts of energy that, when released, can hurl billions of tons of material out into space in eruptions called Coronal Mass Ejections (CMEs) or solar storms.

The latest storm identified by the project is predicted to hit Earth at 07.32 GMT on 13 December. Solar storms have the potential to interfere with communication satellites, upset GPS navigation systems and also pose a health risk to astronauts on the International Space Station. In severe cases they can even knock out entire power grids causing widespread disruption here on Earth. On a gentler note, the particles making up a solar storm can produce beautiful displays of the Northern and Southern Lights as they collide with the Earth's upper atmosphere. Scientists are not overly concerned about the effects of the current storm, but the early warning provided by Solar Stormwatch will allow precautionary measures to be put in place.

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]]> STEREO Sees the Farside of the Sun, Feb. 2011 /gallery/item.php?id=sciencevisuals&iid=12 Illustration of the positions of the two STEREO spacecraft show that they attain 180 degrees of separation in Feb. 2011, thus allowing the world to see the entire Sun for the first time.

]]> STEREO sees Mercury's tail /news/MercurysTail.shtml Scientists from Boston University's Center for Space Physics (CSP) reported the presence of a comet-like tail in images of the planet Mercury taken by STEREO, in a presentation given September 22, 2010 at the European Planetary Science Congress (EPSC) meeting in Rome.

]]> Zig-Zagging Solar Storms http://www.thesuntoday.org/?p=338 Solar researchers have used a novel set of techniques using STEREO data that allow them to watch the acceleration and deflection of coronal mass ejections with unprecedented precision.

]]> Coronal Mass Ejection Headed for Earth https://www.nasa.gov/topics/solarsystem/sunearthsystem/main/News080210-cme.html On August 1st around 0855 UT, Earth orbiting satellites detected a C3-class solar flare. The origin of the blast was Earth-facing sunspot 1092. C-class solar flares are small (when compared to X and M-class flares) and usually have few noticeable consequences here on Earth besides aurorae. This one has spawned a coronal mass ejection heading in Earth's direction.

]]> A 3D Solar Wave /gallery/item.php?id=stereoimages&iid=127 When a coronal mass ejection (CME) erupts from the Sun, movies in extreme ultraviolet light often show enormous waves, spreading over a large area on the solar surface, just as tsunamis travel far from the original seismic event. Now STEREO data have been used to show that these waves are the footprints of giant domes that spread upward into the corona as well as outward across the surface.

]]> STEREO spacecraft catch comet diving into Sun /gallery/item.php?id=stereoimages&iid=125 Using instruments aboard NASA's twin STEREO spacecraft, four post-doctoral fellows at UC Berkeley's Space Sciences Laboratory were able to track the comet as it approached the Sun (Mar. 11-12, 2010) and estimate an approximate time and place of impact.

]]> Sun Erupts: Epic Blast Seen by NASA Solar Observatory http://news.nationalgeographic.com/news/2010/04/100423-sun-eruption-nasa-space-science-solar-observatory/ NASA's new Solar Dynamics Observatory may be getting all the press this week for its retina-searing first pictures of the sun. But two old sun-observing warhorses recently showed they're not quite ready for pasture yet.

]]> Solar Story: Understanding the Sun http://www.nmm.ac.uk/visit/exhibitions/past/solar-story/ STEREO featured live and on-line in a new exhibition at the UK National Maritime Museum

]]> Solar Storm Watch http://solarstormwatch.com/ Solar scientists need you! Help them spot explosions on the Sun and track them across space to Earth. Your work will give astronauts an early warning if dangerous solar radiation is headed their way. And you could make a new scientific discovery.

]]> STEREO iPhone App http://3dsun.org/ A new free application for iPhones lets you access up-to-date global views of the Sun from STEREO along with solar activity alerts and other features. With this application, you can interactively view the Sun from any angle, and zoom in on features of interest, based on combined images from both STEREO spacecraft.

]]> Wondering what those odd sphere-like features are in recent STEREO EUVI images? /artifacts/artifacts.shtml We have investigated, and determined that these are artifacts caused by an interaction between the high compression factors used for the beacon data, and cosmic ray events on the detector. Our discussion of image artifacts has been updated to include this phenomenon. Another factor which has contributed to this issue has been the recent delay in receiving the full resolution images from the spacecraft. This was caused by a server problem at the Deep Space Network, and has now been resolved.

]]> Do Solar Tsunami's Exist? /news/SolarTsunami.shtml STEREO Captures Sun's Eruption https://www.nasa.gov/mission_pages/stereo/multimedia/filament_eruption.html May 15,2009 -- Mysterious comets and igniting planets? No, they're mostly just ghosts... http://sungrazer.nrl.navy.mil/index.php?p=news_arch89#ghosts Gravity wells could provide parking lots for spaceships http://www.mcclatchydc.com/homepage/story/71824.html STEREO Spies First Major Activity of Solar Cycle 24 https://www.nasa.gov/mission_pages/stereo/news/solarcycle24.html NASA'S STEREO spacecraft reveals anatomy of a solar storm in 3-D. /news/anatomy/anatomy.shtml STEREO-20: Coming soon to a night sky near you! http://sungrazer.nrl.navy.mil/index.php?p=latest_news STEREO Hunts for Remains of an Ancient Planet near Earth http://science.nasa.gov/headlines/y2009/09apr_theia.htm?list20318 Join STEREO and Explore Gravitational "Parking Lots" That May Hold Secret of Moon's Origin https://www.nasa.gov/mission_pages/stereo/news/gravity_parking.html Black Rain http://www.semiconductorfilms.com/root/Black_Rain/Black_Rain.htm 100 Hours of Astronomy. Around the world in 80 telescopes. http://www.100hoursofastronomy.org/program/75-live-24-hour-research-observatory-webcast ]]> Do gravity holes harbour planetary assassins? http://www.newscientist.com/article/mg20126962.000-do-gravity-holes-harbour-planetary-assassins.html?full=true NASA Sees the 'Dark Side' of the Sun http://science.nasa.gov/headlines/y2009/23jan_darkside.htm?list20318 STEREO IN QUADRATURE /news/Quadrature.shtml SECCHI Makes a Fantastic Recovery! /gallery/item.php?gid=1&id=85 Solar Flare Surprise http://science.nasa.gov/headlines/y2008/15dec_solarflaresurprise.htm No separation anxiety for STEREO /gallery/item.php?gid=stereoimages&id=76 Twisting Solar Jets in STEREO /gallery/item.php?gid=1&id=66 solarjets STEREO has made possibly the first 3D measurements of a solar jet. Jets are columns of super hot plasma (hot ionized gases at over a million degrees) which shoot out from the sun over the course of just a few minutes - this one reached velocities of 300 km/s (650,000 miles/hour). It was over 10,000 kilometers high and nearly half as wide as the Earth.

STEREO observed it from two points of view 11 degrees apart. With these images it could be clearly seen that the jet was twisted. This twist is important. It agrees with models of jets in which they are caused by the twisting of magnetic field lines. Highly twisted magnetic fields eventually become unstable, much like an over-wound spring. When the writhing fields come into contact with nearby untwisted fields that extend into the solar wind, the twist is transferred to those very long field lines. The twist then rapidly leaves the Sun, pushing the plasma outward at high speed.

]]> Solar Tsunami - May 19, 2007 /gallery/item.php?id=stereoimages&iid=58

The figure shows a sequence of three 195 A difference images obtained by the EUVI instrument on STEREO taken on May 19, 2007. The images show a tsunami blasting through the Sun's atmosphere at millions of kilometers per hour.

]]> STEREO: The Sun's Corona Unraveled in 3D http://www.skyandtelescope.com/news/16681321.html At the largest scale, the Sun's corona (outermost atmosphere) consists of so-called streamers: huge, pointy cones of enhanced density. On a more basic level, everything in the corona is made up of overlapping loops, sometimes with their tops blown indefinitely upward. The Science Gallery launched at TCD with LIGHTWAVE exhibition http://www.tcd.ie/Communications/news.php?headerID=822&vs_date=2008-2-1 View the movie on youtube about this exhibit. STEREO is not mentioned until the end.]]> Celestial tsunamis https://www.nasa.gov/mission_pages/stereo/news/killer_electrons.html U physicists discover powerful radio waves that may lead to spacecraft damage. The culprit? The most powerful radio waves of their kind ever detected in the Belts. The researchers not only discovered the waves but showed that they are capable of accelerating electrons to near the speed of light--which gives the electrons enough energy to knock out computers, pierce spacesuits, and damage the tissues of astronauts--and that they can do it astonishingly fast. What's the Angle? /gallery/item.php?id=stereoimages&iid=53 The two STEREO spacecraft have been slowly separating over most of the mission, so that now they are 44 degrees apart as of Jan. 8, 2008. They will continue to separate as the mission proceeds. So, what does this gain us? Well, for a time we could generate real 3D images and movies of the Sun for the first time. But there is another major advantage to the widening angle. Twin Probes Watch Sun's Fury in 3-D http://discovermagazine.com/2008/jan/twin-probes-watch-sun2019s-fury-in-3-d Astronomers got a new perspective on the sun in April, when NASA's Solar Terrestrial Relations Observatory (STEREO) probes began sending back the first three-dimensional images of our nearest star. NASA built the twin spacecraft to learn more about coronal mass ejections, or CMEsbillion-ton spitballs of electrically charged particles that sporadically fire off from the sun. When CMEs slam into Earth, their electric fields can blow out the circuits of communications satellites or overload regional power grids. "Anything that's electromagnetic can be affected by their charged particles," says NASA astrophysicist Madhulika Guhathakurta, a program scientist for STEREO. Stellar variability studies with STEREO's Heliospheric Imager /news/StellarVariability.shtml STEREO's Heliospheric Imagers are ideally placed for observing stellar variability. The nature of the synoptic observations means that stars can be tracked continuously through the 2 cameras on both spacecraft for up to 180 days. In some cases, it has taken ground based astronomers years to accumulate enough data to study a star's variability. Imaging the Solar Winds as it Sweeps Past Earth /news/SolarWindEarth.shtml Data from STEREO's SECCHI Heliospheric Imagers have been used to image gusts in the solar wind as they go by the Earth Planet identification in STEREO coronagraph images /news/Planet_id.shtml We've been getting a lot of questions lately asking what this small round object was that passed through the COR2-Ahead field of view from December 22nd to January 2nd. Hence, we decided to post this to answer everybody's questions. It's the planet Mercury. Video Q&A /videoQA/videoQA.shtml Questions with Answers from STEREO Team Members Naked Science - "Solar Force" http://channel.nationalgeographic.com/channel/nakedscience/videos_2.html http://channel.nationalgeographic.com/channel/ET/daily/20071030.html
It will replay a number of times after that.]]> NASA Satellite Sees Solar Hurricane Tear Comet Tail Off https://www.nasa.gov/mission_pages/stereo/news/encke.html
NASA's STEREO satellite captured the first images ever of a collision between a solar "hurricane", called a coronal mass ejection (CME), and a comet. The collision caused the complete detachment of the comet's plasma tail. Comets are icy leftovers from the solar system's formation billions of years ago. They usually hang out in the cold, distant regions of the solar system, but occasionally a gravitational tug from a planet, another comet, or even a nearby star sends them into the inner solar system. Once there, the sun's heat and radiation vaporizes gas and dust from the comet, forming its tail. Comets typically have two tails, one made of dust and a fainter one made of electrically conducting gas, called plasma.]]> Path of Totality: The Movie https://www.nasa.gov/vision/earth/everydaylife/eclipse_libya.html On March 29, 2006, a NASA-led science expedition, including a number of STEREO team members, traveled to Tripoli and then the Sahara desert to witness and study -- first hand -- a total solar eclipse. This international expedition was an unprecedented collaboration with Libyan scientists and researchers from across the globe. NASA produced a high definition video documentary of the expedition and its interactions with Libya academics and government officials. New Film Opening in Boston Gives First 3D Look at the Sun http://www.3dsunfilm.com/

NASA's STEREO Mission, the scientists involved and the vital information that they gather and study, is being presented in a new digital 3D film titled "3D Sun." 3D Sun will bring these images to the world in a way that has only been imagined before. 3D Sun opened at the Boston Museum of Science the first week of September.]]> 3D Photo Showcase /gallery/3dshowcase.shtml We invite you to send us your 3D photos so that we can feature them on our web site. The 3D effect is fun to see and we want to show off what our readers have come up with. The photos need to be in the red/cyan anaglyph mode so that all viewers can see them with standard 3D glasses. (We are willing to show Left/Right pairs (in addition to the anaglyphs). Anatomy of a solar storm http://www.cnn.com/2007/TECH/space/06/07/solar.storm.anatomy/index.html Though we can't yet predict such storms, it's only a matter of time. Space-weather forecasters use satellites and ground-based scopes to monitor sunspots for flares and CMEs but can't tell with certainty if or when they will hit Earth. The STEREO satellites will help scientists determine whether a particular storm is headed for us and, hopefully, will give satellite and energy-grid minders enough warning to prepare for a hit. STEREO's Press Clippings /3drelease/3darticles.shtml The STEREO 3D Press Conference has received a large amount of media attention. Click here to view all the press clippings. STEREO Ultraviolet 3D Images /3drelease/3dultraviolet.shtml The two STEREO spacecraft were launched together in Oct. 2006 from Cape Canaveral. In the following months they were placed in two separate orbits about the Sun - one (the Ahead spacecraft) moving ahead of Earth's orbit, the other (Behind) moving behind Earth's orbit. Both spacecraft are separating from each other and Earth. The spacecraft now have four degrees of separation, enough to provide true 3D images of the Sun and solar storms for the very first time. The Sun in 3D! - Museum List /3drelease/3drelease.shtml On April 23, NASA will unveil 3-D images of the sun from NASA's Solar TErrestrial RElations Observatory (STEREO) on the web, television and museums across the country. For first time, scientists will be able to see structures in the Sun's atmosphere in three dimensions. New Solar Images Herald Better Solar Storm Tracking https://www.nasa.gov/mission_pages/stereo/news/panorama_media.html NASA researchers will be discussing the remarkable imagery from the recently launched STEREO spacecraft. For the first time, scientists are now able to track solar storms from the sun to Earth using the latest images from NASA's twin STEREO spacecraft. Images supporting the telecon will be available at this site on Thursday morning. Solar Eclipse, STEREO Style /gallery/item.php?id=stereoimages&iid=8 On Feb. 25, 2007 there was a transit of the Moon across the face of the Sun - but it could not be seen from Earth. This sight was visible only from the STEREO-B spacecraft in its orbit about the sun, trailing behind the Earth. The "Behind" spacecraft leaves Earth orbit. /img/spacecraft/STEREO_phasing.mov Jan. 22, 2007 The "Behind" spacecraft leaves Earth orbit for its orbit about the sun. Now both spacecraft are in thier final sun-centric orbits. Comet McNaught - A First Light Present for STEREO /gallery/item.php?id=stereoimages&iid=1 An instrument on one of the two new STEREO spacecraft captured an unprecedented view of the brightest comet of the last 40 years. STEREO First Light Press Release https://www.nasa.gov/mission_pages/stereo/news/first_light.html NASA's twin Solar Terrestrial Relations Observatories (STEREO) sent back their first images of the sun this week and with them a view into the sun's mounting activity. STEREO Learning Center | Extreme Ultraviolet Images /classroom/EUVsun.shtml It is not possible for the human eye to see ultraviolet light directly. Thus, the colors of these images are just ways to represent them so we can see them. To keep the images straight, we assign certain colors to EUVI images taken in particular extreme ultraviolet (EUV) wavelengths, so usually the 195 images are in green, the 304 images are in orange, etc. STEREO Learning Center | Coronagraph Images /classroom/coronagraphs.shtml A Coronagraph is an instrument which studies the Sun's outer atmosphere, the corona. From Earth the corona is most easily seen during a total solar eclipse.