Astronomy Picture of the Day Search Results for "stereo"

APOD: 2008 October 4 - A Solar Prominence Unfurls
Explanation: On September 29, this magnificent eruptive solar prominence lifted away from the Sun's surface, unfurling into space over the course of several hours. Suspended in twisted magnetic fields, the hot plasma structure is many times the size of planet Earth and was captured in this view by the Sun-watching STEREO (Ahead) spacecraft. The image was recorded in extreme ultraviolet light emitted by ionized Helium, an element originally identified in the solar spectrum. Seen against the brilliant solar surface in visible light, such prominences appear as dark filaments because they are relatively cool. But they are bright themselves when viewed against the blackness of space, arcing above the Sun's edge. A video of the eruption (a 2.6MB .mov file) is available here.

APOD: 2008 August 10 - The Eagle Rises
Explanation: Get out your red/blue glasses and check out this remarkable stereo view from lunar orbit. Created from two photographs (AS11-44-6633, AS11-44-6634) taken by astronaut Michael Collins during the 1969 Apollo 11 mission, the 3D anaglyph features the lunar module ascent stage, dubbed The Eagle, as it rises to meet the command module in lunar orbit. Aboard the ascent stage are Neil Armstrong and Buzz Aldrin, the first to walk on the Moon. The smooth, dark area on the lunar surface is Mare Smythii located just below the equator on the extreme eastern edge of the Moon's near side. Poised beyond the lunar horizon, is our fair planet Earth.

APOD: 2008 July 6 - Apollo 17 VIP Site Anaglyph
Explanation: Get out your red/blue glasses and check out this stereo scene from Taurus-Littrow valley on the Moon! The color anaglyph features a detailed 3D view of Apollo 17's Lunar Rover in the foreground -- behind it lies the Lunar Module and distant lunar hills. Because the world was going to be able to watch the Lunar Module's ascent stage liftoff via the rover's TV camera, this parking place was also known as the VIP Site. In December of 1972, Apollo 17 astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours on the Moon, while colleague Ronald Evans orbited overhead. The crew returned with 110 kilograms of rock and soil samples, more than from any of the other lunar landing sites. Cernan and Schmitt are still the last to walk (or drive) on the Moon.

APOD: 2008 February 23 - Stereo Space Station
Explanation: Get out your red-blue glasses and float next to the International Space Station (ISS), planet Earth's largest artificial moon. This fun stereo view was constructed from parts of two separate images (S122-E-009880, S122-E-009893) and an additional background recorded as the shuttle orbiter Atlantis undocked from the ISS on February 18. Atlantis and the ISS were traveling over 7,500 meters per second at an altitude of about 350 kilometers. The shiny, 7 meter long module extending from the station at the lower right is ESA's Columbus Laboratory, delivered by Atlantis and installed by spacewalking astronauts. After a successful 13 day mission to the ISS, Atlantis landed at Kennedy Space Center on Wednesday.

APOD: 2007 October 3 - Comet Encke s Tail Ripped off
Explanation: Swinging inside the orbit of Mercury, on April 20th periodic comet Encke encountered a blast from the Sun in the form of a Coronal Mass Ejection (CME). When CMEs, enormous clouds of energetic particles ejected from the Sun, slam into Earth's magnetosphere, they often trigger auroral displays. But in this case, the collison carried the tail of the comet away. The tail was likely ripped off by interacting magnetic fields rather than the mechanical pressure of the collision. Clicking on the two panel image will play a movie gif of the remarkable event as recorded by the Heliospheric Imager onboard the STEREO A spacecraft. In the movie, the time between frames is about 45 minutes, while the frames span about 14x20 million kilometers at the distance of the comet. Of course, similar collisions have happened before as the ancient comet loops through its 3.3 year solar orbit. So don't worry, Encke's tail grows back!

APOD: 2007 September 15 - Iapetus: 3D Equatorial Ridge
Explanation: This bizarre, equatorial ridge extending across and beyond the dark, leading hemisphere of Iapetus gives the two-toned Saturnian moon a distinct walnut shape. With red/blue glasses you can check out a remarkable stereo composition of this extraordinary feature -- based on close-up images from this week's Cassini spacecraft flyby. In fact, the ridge's combination of equatorial symmetry and scale, about 20 kilometers wide and reaching up to 20 kilometers above the surface, is not known to be duplicated anywhere else in our solar system. The unique feature was discovered in Cassini images from 2004. It appears to be heavily cratered and therefore ancient, but the origin of the equatorial ridge on Iapetus remains a mystery.

APOD: 2007 July 20 - Apollo 11: East Crater Panorama
Explanation: On July 20, 1969, Apollo 11 astronauts Neil Armstrong and Edwin "Buzz" Aldrin became the first to walk on the Moon. This panorama of their landing site sweeps across the magnificent desolation of the Moon's Sea of Tranquility, with their Lunar Module, the Eagle, in the background at the far left. East Crater, about 30 meters wide and 4 meters deep, is on the right (scroll right), and was so named because it is about 60 meters east of the Lunar Module. Armstrong had piloted the Eagle safely over the crater. Near the end of his stay on the lunar surface Armstrong strayed far enough from the Lunar Module to take the pictures used to construct this wide-angle view, his shadow appearing at the panorama's left edge. The object near the middle foreground is a stereo close-up camera.

APOD: 2007 July 1 - Steep Cliffs on Mars
Explanation: Vertical cliffs of nearly two kilometers occur near the North Pole of Mars. Also visible in the above image of the Martian North Polar Cap are red areas of rock and sand, white areas of ice, and dark areas of unknown composition but hypothesized to be volcanic ash. The cliffs are thought to border volcanic caldera. Although the sheer drop of the Martian cliffs is extreme, the drop is not as deep as other areas in our Solar System, including the 3.4-kilometer depth of Colca Canyon on Earth and the 20 kilometer depth of Verona Rupes on Uranus' moon Miranda. The above image, digitally reconstructed into a perspective view, was taken by the High Resolution Stereo Camera on board the ESA's robotic Mars Express spacecraft currently orbiting Mars.

APOD: 2007 June 23 - 3D Barringer Meteorite Crater
Explanation: Barringer Meteorite Crater, near Winslow, Arizona, is one of the best known impact craters on planet Earth. View this color stereo anaglyph with red/blue glasses to get a dramatic sense of the crater's dimensions -- one mile wide, and up to 570 feet deep. (A cross-eyed stereo pair is available here.) Historically, this crater is the first recognized to be caused by an impact rather than a volcanic eruption. Modern research indicates that the impactor responsible, a 300,000 ton nickel-iron meteor, struck some 50,000 years ago. Estimates suggest that it was about 130 feet across and was traveling over 26,000 miles per hour. For comparison, the asteroid or comet impactor that created the Chicxulub crater 65 million years ago, and is thought to have caused the extinction of the dinosaurs, was 6 to 12 miles across.

APOD: 2007 June 2 - 3D Full Moon
Explanation: Get out your red/blue glasses and check out this satisfying stereo anaglyph of the Full Moon. A corresponding stereo image pair, intended for cross-eyed viewing, is also available through this link. Regardless of your preferred technique for stereo viewing, the 3D effect comes from combining pictures of the same scene taken at different angles -- mimicking the slightly different perspective of each eye. Perhaps surprisingly for Earthdwellers, getting two pictures of the Full Moon from different angles only requires a little patience. In this case, photographer Laurent Laveder used pictures taken months apart, one in November 2006 and one in January 2007. He relied on the Moon's continuous libration or wobble as it orbits to produce two shifted images of a Full Moon.

APOD: 2007 May 4 - The Iron Tail of Comet McNaught
Explanation: Outstanding in planet Earth's sky early this year, Comet McNaught is captured in this view from the STEREO A spacecraft. McNaught's coma is so bright, it blooms into the long horizontal stripe at the bottom of the field. Brilliant Venus, near the top left corner, also produces a severe horizontal blemish in the digital image. But the sensitive camera does accurately record the striations in McNaught's famous dust tail along a region stretching over 30 million kilometers toward the top right of the field of view. A separate, fainter, arching tail just to the left of the dust tail was initially thought to be an example of a common ion tail, formed by electrically charged atoms carried away from the comet by the solar wind. However, detailed modeling indicates that tail is actually due to neutral iron atoms pushed out by the pressure of sunlight -- the first ever detected neutral iron tail from a comet. The iron atoms are thought to originate in dust grains from the comet nucleus that contain the iron-sulfur mineral troilite (FeS).

APOD: 2007 April 24 - The Sun in Three Dimensions
Explanation: What does the Sun look like in all three spatial dimensions? To find out, NASA launched two STEREO satellites to perceive three dimensions on the Sun much like two eyes allow humans to perceive three dimensions on the Earth. Such a perspective is designed to allow new insight into the surface of the rapidly changing Sun, allowing humans to better understand and predict things like Coronal Mass Ejections and solar flares that affect the Earth as well as satellites and astronauts orbiting the Earth. Pictured above are two simultaneous images of the Sun taken by STEREO A and STEREO B, now digitally combined to give one of the first 3-D pictures of the Sun ever taken. To fully appreciate the image, one should view it with 3-D red-blue glasses. The teeming and bubbling solar surface can be seen sporting a prominent solar prominence near the top of the image.

APOD: 2007 April 21 - 3D Face on Mars
Explanation: Get out your red/blue glasses and gaze down on this weathered mesa on Mars. Of course, described as a rock formation that resembles a human head in a 1976 NASA press release, this mesa is also famous as the Face on Mars. The sharp stereo image was created by combining high resolution pictures from cameras on two different spacecraft in Mars orbit - Mars Reconnaissance Orbiter and Mars Global surveyor. It shows rugged details of the approximately 2 kilometer wide, isolated hill - similar to mesa landforms on planet Earth - rising some 240 meters above the plains of the martian Cydonia region. This remarkable 3D view exaggerates the hill's vertical dimensions.

APOD: 2007 March 3 - Lunar Transit from STEREO
Explanation: A million miles from planet Earth, last weekend the STEREO B spacecraft found itself in the shadow of the Moon. So, looking toward the Sun, extreme ultraviolet cameras onboard STEREO B were able to record a stunning movie of a lunar transit (aka solar eclipse), as the Moon tracked across the solar disk. Each frame of the movie is a false-color composite of images made through four different filters that highlight temperature regimes and structures in the upper solar atmosphere. In this frame, large bright active regions, seen as dark sunspots in visible light, flank the Moon's silhouetted disk. The Moon appears small, less than 1/4th the size seen from Earth, because the spacecraft-Moon separation is over four times the Earth-Moon distance. Tonight, the Moon will find itself in planet Earth's shadow in a total lunar eclipse.

APOD: 2007 February 17 - Stereo Eros
Explanation: Get out your red/blue glasses and float next to asteroid 433 Eros, now over 220 million kilometers away! Orbiting the Sun once every 1.8 earth-years, asteroid Eros is a diminutive 40 x 14 x 14 kilometer world of undulating horizons, craters, boulders and valleys. Its unsettling scale and bizarre shape are emphasized in this picture - a mosaic of images from the NEAR Shoemaker spacecraft processed to yield a stereo anaglyphic view. Along with dramatic chiaroscuro, NEAR's 3-D imaging provided important measurements of the asteroid's landforms and structures, and clues to the origin of this city-sized chunk of solar system. The smallest features visible here are about 30 meters across. After spending a year in orbit around Eros, the historic Near Shoemaker spacecraft made the first ever landing on an asteroid's surface February 12, 2001.

APOD: 2007 January 17 - Comet McNaught from New STEREO Satellite
Explanation: The brightest comet of recent decades was a surprising first sight for a new camera in space. The Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) instrument onboard the Solar TErrestrial RElations Observatory (STEREO) satellite had just opened up on January 11 when it snapped the above image of Comet McNaught. Visible was a spectacular view of the ion tail of Comet McNaught being swept away from the Sun by the solar wind in filamentary rays. The comet tail is seen to extend at least seven degrees across the above image, while the central coma is so bright it saturates. Comet McNaught is now reportedly so bright that it is visible even in broad daylight by blocking out the Sun with your hand. Comet McNaught has rounded the Sun and will slowly fade away for observers in Earth's Southern Hemisphere as it recedes from the Sun.

APOD: 2006 December 22 - The View from Stereo Ahead
Explanation: On December 22nd, at 0022 Universal Time the Sun reached its southernmost point in Earth's sky marking the final season change for the year 2006. In celebration of the Solstice, consider these images of the Sun from an extreme ultraviolet telescope onboard the Stereo Ahead spacecraft. Recorded on December 4th, Stereo's first day of imaging, each false-color view highlights atomic emission in different temperature regimes of the upper solar atmosphere; 2 million kelvins in yellow, 1.5 million in green, 1 million, in blue and 60 to 80 thousand in red. The Stereo Mission will place twin spacecraft, launched together in October, into different solar orbits to conduct a three dimensional exploration of the Sun and the solar environment. After completing lunar swingby maneuvers, the A spacecraft is intended to orbit the Sun "Ahead" of planet Earth, and the B spacecraft "Behind".

APOD: 2006 November 25 - 3D Mercury Transit
Explanation: Mercury is now visible shortly before dawn, the brightest "star" just above the eastern horizon. But almost two weeks ago Mercury actually crossed the face of the Sun for the second time in the 21st century. Viewed with red/blue glasses, this stereo anaglyph combines space-based images of the Sun and innermost planet in a just-for-fun 3D presentation of the Mercury transit. The solar disk image is from Hinode. (sounds like "hee-no-day", means sunrise). A sun-staring observatory, Hinode was launched from Uchinoura Space Center and viewed the transit from Earth orbit. Superimposed on Mercury's dark silhouette is a detailed image of the planet's rugged surface based on data from the Mariner 10 probe that flew by Mercury in 1974 and 1975.

APOD: 2006 September 30 - STS 115: Stereo Portrait
Explanation: On September 12, astronaut Heidemarie Stefanyshyn-Piper snapped photos of her colleague Joseph Tanner during the STS-115 mission. At the time, the spacesuited pair were working outside the shuttle orbiter Atlantis, some 300 kilometers above planet Earth. Portions of two of the pictures (S115-E-05750 and S115-E-05753) have been combined in this spectacular 3D image - a stereo anaglyph intended to be viewed with red/blue glasses. Included in the scene reflected in Tanner's visor is Stefanyshyn-Piper herself and the Sun shining above the Earth's distant horizon.

APOD: 2006 September 16 - Discovery Orbiter Anaglyph
Explanation: Approaching the International Space Station on STS-121 in July, the Shuttle Orbiter Discovery posed for a series of photographs. The process was part of an inspection to check for damage to the orbiter, but against the backdrop of planet Earth 300 kilometers below, the pictures themselves are stunning. Stereo artist Patrick Vantuyne has combined two of them (ISS013e48787 and ISS013e48788) to produce this dramatic 3D image. The stereo anaglyph is intended to be viewed with red/blue glasses. Details visible along the forward fuselage include high temperature (black) and low temperature (white) insulation tiles, thrusters used for steering and attitude control, and crew compartment windows.

APOD: 2006 August 26 - Apollo 17 VIP Site Anaglyph
Explanation: Get out your red/blue glasses and check out this stereo scene from Taurus-Littrow valley on the Moon! The color anaglyph features a detailed 3D view of Apollo 17's Lunar Rover in the foreground -- behind it lies the Lunar Module and distant lunar hills. Because the world was going to be able to watch the Lunar Module's ascent stage liftoff via the rover's TV camera, this parking place was also known as the VIP Site. In December of 1972, Apollo 17 astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours on the Moon, while colleague Ronald Evans orbited overhead. The crew returned with 110 kilograms of rock and soil samples, more than from any of the other lunar landing sites. Cernan and Schmitt are still the last to walk (or drive) on the Moon.

APOD: 2006 August 4 - Burns Cliff Anaglyph
Explanation: Get out your red/blue glasses and gaze across Burns Cliff along the inner wall of Endurance crater on Mars! The view from the perspective of Mars rover Opportunity is a color anaglyph - two different images are presented to the left and right eyes by color filters to produce the 3D effect. Scroll the picture to the right to see the full 180 degree panorama. Still returning science data and images, both Spirit and Opportunity rovers completed 2 years of Mars exploration in January. Opportunity spent the month of July on the road to Victoria crater. The stereo pair of images used to create this view are based on image data recorded in November 2004.

APOD: 2005 November 26 - A Stereo Sun
Explanation: A stereo view of the closest star, this creatively composited image was constructed from an extensive archive of pictures taken between March 2004 and April 2005. When viewed with red/blue glasses, the Sun's disk and surface features, including sunspots, filaments, and prominences, stand out in an exaggerated stereo perspective. The images were recorded through a narrow band hydrogen-alpha filter, designed to transmit only light from hydrogen atoms in the solar atmosphere. After combining the solar hydrogen-alpha images, a 3D star field was added to the final anaglyphic stereo view.

APOD: 2005 August 27 - 3D International Space Station
Explanation: Get out your red-blue glasses and float next to the International Space Station (ISS), planet Earth's largest artificial moon. This breathtaking stereo view was constructed from two separate images (S114-E-7245, S114-E-7246) recorded as the shuttle orbiter Discovery undocked from the ISS on August 6. As seen here, from left to right the ISS structure covers about 27 meters (90 feet). The span from the automated Progress supply ship docked in the foreground to the Destiny module hidden behind the station structure is about 52 meters (171 feet) long, while the full (top to bottom) reach of the solar arrays at the left would cover about 73 meters (240 feet). Resupplied by Discovery, the ISS is currently operated by the two member Expedition 11 crew, Sergei Krikalev and John Phillips.

APOD: 2005 March 15 - Steep Cliffs on Mars
Explanation: Vertical cliffs of nearly two kilometers occur near the North Pole of Mars. Also visible in the above image of the Martian North Polar Cap are red areas of rock and sand, white areas of ice, and dark areas of unknown composition but hypothesized to be volcanic ash. The cliffs are thought to border volcanic caldera. Although the sheer drop of the Martian cliffs is extreme, the drop is not as deep as other areas in our Solar System, including the 3.4-kilometer depth of Colca Canyon on Earth and the 20 kilometer depth of Verona Rupes on Uranus' moon Miranda. The above image, digitally reconstructed into a perspective view, was taken by the High Resolution Stereo Camera on board the ESA's robotic Mars Express spacecraft currently orbiting Mars.

APOD: 2005 February 17 - Melas, Candor, and Ophir: Valleys of Mariner
Explanation: First imaged by the Mariner 9 spacecraft, Valles Marineris, the grand canyon of Mars, is a system of enormous depressions or chasmas that stretch some 4,000 kilometers along the Martian equator. Looking north over the canyon's central regions, dark Melas Chasma lies in the foreground of this spectacular perspective view. Behind it are Candor Chasma and the steep walls of Ophir Chasma near the horizon. Faulting, surface collapse and landslides are seen to be part of the complex geologic history of these dramatic features, with layered deposits also found within the canyon system. Recorded in 2004, the image represents data from the High Resolution Stereo Camera (HRSC) on board ESA's Mars Express spacecraft. Melas, Candor and Ophir are about 200 kilometers wide and 5 to 7 kilometers deep.

APOD: 2005 February 12 - NEAR at Eros: Before Touchdown
Explanation: On 12 February, 2001, the NEAR-Shoemaker spacecraft gently touched-down on the surface of Eros -- the first ever landing on an asteroid. During the descent, the spacecraft's camera recorded successive images of the diminutive world's surface, revealing fractured boulders, dust filled craters, and a mysterious collapsed channel. The last frame, seen in the above montage at the far left, was taken at a range of 128 meters. Expanded in the inset, it shows surface features a few centimeters across. Stereo experimenter Patrick Vantuyne, constructed this montage from the final images in the landing sequence, carefully identifying the overlapping areas in successive frames. Frames which overlap were taken by the spacecraft from slightly different viewpoints, allowing Vantuyne to construct close-up stereo images of the surface of asteroid 433 Eros.

APOD: 2004 November 20 - Stereo Phobos
Explanation: Get out your red/blue glasses and float next to Phobos, grooved moon of Mars! Also featured in yesterday's episode, the image data from the Mars Express High Resolution Stereo Camera was recorded at a distance of about 200 kilometers. This tantalizing stereo anaglyph view shows the Mars-facing side of the asteroid-like moon's cratered and grooved surface. Up to hundreds of meters wide, the mysterious grooves may be fractures related to the impact which created 10 kilometer wide Stickney crater, the large crater at the left.

APOD: 2004 September 30 - Crater Wall on Solis Planum
Explanation: This dramatic perspective view looks south-east along the wall of a large eroded impact crater on Solis Planum, bordering the mountainous Thaumasia region of Mars. Stretching for about 50 kilometers into the scene, the crater wall is around 800 meters high. Located just south and west of the Red Planet's grand Valles Marineris, this area features mountains and fault lines that are seen as evidence of surface plate motions or plate tectonics. The process of plate tectonics has long been shaping the surface of planet Earth but is thought to have been only briefly active on Mars. The image was constructed using color image data from the High Resolution Stereo Camera onboard ESA's Mars Express spacecraft.

APOD: 2004 July 29 - Melas Chasma
Explanation: Steep cliffs drop into the rugged terrain of Melas Chasma in this stunning view from the Mars Express spacecraft orbiting the Red Planet. At a scale of 16 meters per pixel, the image data from the orbiter's High Resolution Stereo Camera offers evidence that volcanic activity, water, wind erosion and marsquakes may all have shaped the region. Melas Chasma lies along the central southern edge of the large Valles Marineris, the grand canyon of Mars. While the Valles Marineris is itself over 4,000 kilometers long and up to 10 kilometers deep, the region pictured spans about 70 kilometers. The floor of Melas Chasma seen here is several kilometers below the surrounding plateau.

APOD: 2004 July 27 - Razorbacks in Endurance Crater
Explanation: Over one year after its launch, robot geologist Opportunity has been spending recent sols on Mars inching its way down the slopes of Endurance crater. Littered with martian blueberries, some flat rocks within the crater also seem to have surprising razorbacks -- narrow slabs sticking up along their edges. Like the blueberries, it's possible that the sharp, narrow features are related to water. They could be formed by minerals deposited by water in cracks, with the surrounding softer material subsequently eroded away. How narrow are they? The ones pictured here in an enhanced color image from Opportunity's panoramic camera are actually only a few centimeters high and about half a centimeter wide. Impressive 3D views have been constructed by stereo experimenter P. Vantuyne based on the camera's left and right eye images of the region.

APOD: 2004 July 17 - Transit of Venus Stereogram
Explanation: Venus glides in front of an enormous solar disk in these two frames from the TRACE satellite imaging of the inner planet's 2004 transit. Arranged in a "right/left" stereogram, the frames are intended to be viewed at a comfortable distance from the screen with your eyes gently crossed, allowing the images to merge and produce a pleasing stereo effect. Shown during the ingress (beginning) phase of the transit, the silhouetted portion of the planet appears to float dramatically in front of the Sun's granulated surface. Of course, the dense Cytherian (Venusian) atmosphere also scatters and refracts the intense sunlight. The effect is visible across the portion of the planet still beyond the Sun's edge and viewed against the blackness of space.

APOD: 2004 July 10 - Phoebe Craters in Stereo
Explanation: Get out your red/blue glasses and gaze across the spectacular, cratered terrain of Saturn's icy moon Phoebe in stereo. The dramatic 3-D perspective spans roughly 50 kilometers and is based on two raw, uncalibrated images (N00004840.jpg and N00004838.jpg) from the Cassini spacecraft's narrow angle camera taken during the flyby on June 11 at a range of just over 13,500 kilometers. Phoebe itself is only about 200 kilometers in diameter. Stereo experimenter Patrick Vantuyne noted the substantial overlap in the raw image data and was able to assemble the dramatic view of the overlapping region as a red/blue stereo anaglyph. Looking for a cool project? Stereo glasses can be easily constructed using red and blue plastic for filters. To view this image, the red filter is used for the left eye.

APOD: 2004 January 24 - Valles Marineris from Mars Express
Explanation: Looking down from orbit on January 14, ESA's Mars Express spacecraft scanned a 1700 by 65 kilometer swath across Valles Marineris - the Grand Canyon of Mars - with its remarkable High Resolution Stereo Camera. This spectacular picture reconstructs part of the scanned region from the stereo colour image data recording the rugged terrain with a resolution of 12 metres per pixel. Joining Mars Global Surveyor and Mars Odyssey, Mars Express has been orbiting the red planet since December 25th, returning scientific data, acting as a communications relay, and even making coordinated atmospheric observations with NASA's Spirit rover on the surface. The Beagle 2 lander was released from Mars Express making a landing attempt also on December 25th, but no signal has been received so far.

APOD: 2004 January 8 - The Hills of Mars
Explanation: Distant hills rise above a rocky, windswept plain in this sharp stereo scene from the Spirit rover on Mars. When viewed with red/blue glasses, the picture combines left and right images from Spirit's high resolution panoramic camera to yield a dramatic 3D perspective. The hills were estimated to lie about 2 kilometers away and be approximately 50 to 100 meters high. Along with other features of the landscape, determining their direction and distance will help pinpoint the exact location of the Spirit landing site when compared with high resolution images of the region taken from Mars orbit. Much stereo image data, allowing important estimates of three dimensional shapes, sizes, and distances, is anticipated from the rover's cameras. (Editor's note: Red/blue glasses for viewing stereo pictures can be purchased or simply constructed using red and blue plastic for filters. Try it! To view this image, the red filter is used for the left eye.)

APOD: 2003 March 1 - Stereo Eros
Explanation: Get out your red/blue glasses and float next to asteroid 433 Eros, 170 million kilometers away! Orbiting the Sun once every 1.8 earth-years, asteroid Eros is a diminutive 40 x 14 x 14 kilometer world of undulating horizons, craters, boulders and valleys. Its unsettling scale and bizarre shape are emphasized in this picture - a mosaic of images from the NEAR Shoemaker spacecraft processed to yield a stereo anaglyphic view. Along with dramatic chiaroscuro, NEAR's 3-D imaging provided important measurements of the asteroid's landforms and structures, and clues to the origin of this city-sized chunk of solar system. The smallest features visible here are about 30 meters across. After spending a year in orbit around Eros, the historic Near Shoemaker spacecraft made the first ever landing on an asteroid's surface February 12, 2001.

APOD: 2003 January 11 - Apollo 17: Boulder in Stereo
Explanation: Humans left the Moon over thirty years ago, but donning red-blue glasses (red for the left eye) you can share this excellent stereo perspective view of their last stomping ground. Recorded by Eugene Cernan, the scene depicts his fellow astronaut and geologist Harrison Schmitt next to a large split boulder on the floor of the narrow Taurus-Littrow valley located at the eastern edge of the lunar Mare Serenitatis. Parked nearby, their lunar rover is visible beyond the boulder at the right. During their stay the Apollo 17 astronauts explored the unusually dark terrain at the Taurus-Littrow landing site and deployed explosives to test the internal geology of the Moon. Apollo 17 returned the most lunar rocks and soil samples of any lunar mission.

APOD: 2002 September 7 - Stereo Saturn
Explanation: Get out your red/blue glasses and launch yourself into this stereo picture of Saturn! The picture is actually composed from two images recorded weeks apart by the Voyager 2 spacecraft during its visit to the Saturnian System in August of 1981. Traveling at about 35,000 miles per hour, the spacecraft's changing viewpoint from one image to the next produced this exaggerated but pleasing stereo effect. Saturn is the second largest planet in the Solar System, after Jupiter. Its spectacular ring system is so wide that it would span the space between the Earth and Moon. Although they look solid here, Saturn's rings consist of individually orbiting bits of ice and rock ranging in size from grains of sand to barn-sized boulders.

APOD: 2002 August 28 - 3D Mars: Northern Terra Meridiani
Explanation: In this spectacular 3D stereoscopic view from orbit, steep-sided, flat-topped hills stand above the Terra Meridiani region of Mars. Seen best with red/blue glasses (red for the left eye), the structures are reminiscent of buttes and mesas found in southwestern areas of the North American continent on planet Earth. Like their terrestrial counterparts, these layered martian outcrops apparently formed of hard sedimentary rocks with surrounding softer material eroded away. The possibility that surface water laid down the formations makes the Terra Meridiani region a tempting target for future exploration by Mars landers. But alternative explanations include material deposited by wind or accumulations of volcanic ash. The area pictured is about 3 kilometers across, maybe a thirty minute walk over flat ground. Terrestrial rock climbers take note; you and your equipment would only weigh around 1/3 as much in the lower martian surface gravity.

APOD: 2002 July 13 - Apollo 12: Stereo View Near Surveyor Crater
Explanation: This weekend's stereo picture finds Apollo 12 astronaut Pete Conrad standing on the lunar surface near the southern rim of Surveyor Crater in November of 1969. With red/blue glasses you can gaze beyond the spacesuited Conrad across the magnificent desolation of the Moon's Ocean of Storms. Conrad stands next to large chunks of loose rock, debris from the small impact crater. A sampling scoop is in his right hand and a specially designed tool carrier rests by his left foot as he poses for the picture. His photographer, fellow astronaut Al Bean, captured two separate images (cataloged as AS12-49-7318 and AS12-49-7319) by doing something like a stereo "cha-cha" ... taking the first picture while resting his weight on his right foot and the second after shifting to his left. With the first tinted blue and second red, the pair of pictures were offset and combined to create a 3D anaglyph. Donning red/blue glasses allows the result to be viewed with stereo vision.

APOD: 2001 August 24 - NEAR at Eros: Before Touchdown
Explanation: On 12 February, 2001, the NEAR-Shoemaker spacecraft gently touched-down on the the surface of Eros -- the first ever landing on an asteroid. During the descent, the spacecraft's camera recorded successive images of the diminutive world's surface, revealing fractured boulders, dust filled craters, and a mysterious collapsed channel. The last frame, seen in the above montage at the far left, was taken at a range of 128 meters. Expanded in the inset, it shows surface features a few centimeters across. Stereo experimenter Patrick Vantuyne, constructed this montage from the final images in the landing sequence, carefully identifying the overlapping areas in successive frames. Frames which overlap were taken by the spacecraft from slightly different viewpoints, allowing Vantuyne to construct close-up stereo images of the surface of asteroid 433 Eros.

APOD: 2001 August 15 - Mars: 3-D Dunes
Explanation: Get out your red/blue glasses and treat yourself to this dramatic 3-D view of sand dunes on Mars! The field of undulating dunes is found in Nili Patera, a volcanic depression in central Syrtis Major, the most prominent dark feature on the Red Planet. Two different images from the orbiting Mars Global Surveyor spacecraft were combined to make this stereo picture, one taken in March 1999 and the other recorded in April 2001. Sculpted by winds like the sand dunes of Earth, these particular Martian dunes show no change in shape over the time separating the two images, a period equivalent to about one Martian year. This cropped version of the 3-D picture spans an area around 2 kilometers across. Walking, you might cover that distance in about 20 minutes.

APOD: 2001 April 21 - Apollo 12: Stereo View Near Surveyor Crater
Explanation: This weekend's stereo picture finds Apollo 12 astronaut Pete Conrad standing on the lunar surface near the southern rim of Surveyor Crater in November of 1969. With red/blue glasses you can gaze beyond the spacesuited Conrad across the magnificent desolation of the Moon's Ocean of Storms. Conrad stands next to large chunks of loose rock, debris from the small impact crater. A sampling scoop is in his right hand and a specially designed tool carrier rests by his left foot as he poses for the picture. His photographer, fellow astronaut Al Bean, captured two separate images (cataloged as AS12-49-7318 and AS12-49-7319) by doing something like a stereo "cha-cha" ... taking the first picture while resting his weight on his right foot and the second after shifting to his left. With the first tinted blue and second red, the pair of pictures were offset and combined to create a 3D anaglyph. Donning red/blue glasses allows the result to be viewed with stereo vision.

APOD: 2001 April 7 - Stereo Sun
Explanation: This week's stereo offering features the now famous Active Region 9393, the largest sunspot group in the last 10 years. Viewed with red/blue glasses, the stereo pair of images merges into one 3D representation of the Sun with AR9393 above and right of center. The images were recorded in extreme ultraviolet light and AR9393 is seen as an extensive array of bright patches laced with large graceful loops of arcing plasma. In the extreme ultraviolet, active regions outshine the solar surface, just the reverse of their appearance as dark sunspots against a bright photosphere when viewed in visible light. Recorded 96 minutes apart on March 30 by the space-based SOHO EIT camera, the pair produces an exaggerated but pleasing stereo effect due to solar rotation -- the Sun's surface moving slightly between the two exposures to offer different perspectives.

APOD: 2001 March 10 - Apollo / Suveyor Stereo View
Explanation: Put on your red/blue glasses and gaze into this dramatic stereo view from the surface of the Moon! Inspired by last Saturday's APOD, experimentor Patrick Vantuyne offers this stereo rendering of Apollo 12 astronaut Pete Conrad visiting the Surveyor 3 spacecraft in November of 1969. To create the stereo image, Vantuyne carefully combed through the pictures available for downloading from the Apollo Lunar Surface Journal web site to find two which would make an appropriate "stereo pair". He found a pair that depicted the captivating scene from only slightly different viewpoints, approximating the separation between human eyes. Combining the two separate pictures, one tinted red and the other blue-green, with the correct offset, produces the stereo effect when viewed using red/blue glasses, the red filter covering the left eye. The color filters guide each eye to see only the picture with the correct corresponding viewpoint and the brain interprets the result as normal stereo vision. (Editor's note: While you've got those glasses on ... other web sources of astronomy and space science stereo images include the Mars Path Finder archive and a 3D Tour of the Solar System.)

APOD: 2000 February 24 - Stereo Eros
Explanation: Get out your red/blue glasses and float next to asteroid 433 Eros, 260 million kilometers away! Orbiting the Sun once every 1.8 earth-years, asteroid Eros is a diminutive 40 x 14 x 14 kilometer world of undulating horizons, craters, boulders and valleys. Its unsettling scale and bizarre shape are emphasized in this picture - a mosaic of recent images from the NEAR spacecraft processed to yield a stereo anaglyphic view. Along with dramatic chiaroscuro, NEAR's 3-D imaging provides important measurements of the asteroid's landforms and structures, and hopefully clues to the origin of this city-sized chunk of solar system. The smallest features visible here are about 30 meters across.

APOD: 2000 February 12 - Stereo Saturn
Explanation: Get out your red/blue glasses and launch yourself into this stereo picture of Saturn! The picture is actually composed from two images recorded weeks apart by the Voyager 2 spacecraft during its visit to the Saturnian System in August of 1981. Traveling at about 35,000 miles per hour, the spacecraft's changing viewpoint from one image to the next produced this exaggerated but pleasing stereo effect. Saturn is the second largest planet in the Solar System, after Jupiter. Its spectacular ring system is so wide that it would span the space between the Earth and Moon. Although they look solid here, Saturn's rings consist of individually orbiting bits of ice and rock ranging in size from grains of sand to barn-sized boulders.

APOD: January 30, 1999 - Stereo Saturn
Explanation: Get out your red/blue glasses and launch yourself into this stereo picture of Saturn! The picture is actually composed from two images recorded weeks apart by the Voyager 2 spacecraft during its visit to the Saturnian System in August of 1981. Traveling at about 35,000 miles per hour, the spacecraft's changing viewpoint from one image to the next produced this exaggerated but pleasing stereo effect. Saturn is the second largest planet in the Solar System, after Jupiter. Its spectacular ring system is so wide that it would span the space between the Earth and Moon. Although they look solid here, Saturn's Rings consist of individually orbiting bits of ice and rock ranging in size from grains of sand to barn-sized boulders.

APOD: April 30, 1998 - Mars: Big Crater in Stereo
Explanation: Get out your red/blue glasses and check out this stereo picture of "Big Crater" on Mars! (Pieces of red and blue or green clear plastic will do. Your right eye should look through the red piece.) The stereo perspective was created by combining images from the Mars Global Surveyor spacecraft taken on two different orbits, each with a slightly different viewing angle. At just under a mile in diameter, Big Crater is not all that big but it is an important landmark in the vicinity of the Mars Pathfinder landing site on an ancient flood plain in Ares Vallis. Identifying corresponding smaller scale features in Pathfinder and Surveyor images will help to precisely locate the lander. Meanwhile, the line of sight between the Earth and Mars is approaching the Sun. During this period, known as solar conjunction, communicating with Mars Global Surveyor will be difficult.

APOD: October 29, 1997 - Stereo Saturn
Explanation: Get out your red/blue glasses and launch yourself into this stereo picture of Saturn! The picture is actually composed from two images recorded weeks apart by the Voyager 2 spacecraft during its visit to the Saturnian System in August of 1981. Traveling at about 35,000 miles per hour, the spacecraft's changing viewpoint from one image to the next produced this exaggerated but pleasing stereo effect. Saturn is the second largest planet in the Solar System, after Jupiter. Its spectacular ring system is so wide that it would span the space between the Earth and Moon. Although they look solid here, Saturn's Rings consist of individually orbiting bits of ice and rock ranging in size from grains of sand to barn-sized boulders.

APOD: October 10, 1997 - Mars Pathfinder Super Pan
Explanation: Spectacular details of rover tracks, wind-driven soil, and textured rocks on the Martian surface fill this color mosaic. The view is north-northeast from the Sagan Memorial Station at the Pathfinder landing site on Mars. These images are just part of the "Super Panorama" - a detailed color and stereo imaging data set being compiled by Pathfinder's IMP camera. The data set will be used to derive detailed topographic maps of the landing site and to further explore the mineralogy of the martian rocks and soil. The forward rover deployment ramp and the rock named Barnacle Bill, appear in the foreground at the left while the larger Yogi rock is partly visible at the upper right. Criss-crossing tracks were made by the cruising Sojourner robot rover's spiked wheels. With three wheels on each side, the two foot long rover makes tracks about 1.5 feet apart.

APOD: July 16, 1997 - Mars: Yogi And Friends in 3D
Explanation: A ramp from the Pathfinder lander, the Sojourner robot rover, airbags, a couch, Barnacle Bill, and Yogi Rock appear together in this 3D stereo view of the surface of Mars. Barnacle Bill is the rock just left of the solar-paneled Sojourner and Yogi is the big friendly-looking boulder at the right. The "couch" is the angular rock shape visible on the horizon. Look at the image with red/blue glasses (... or just hold a piece of clear red plastic over your left eye and blue or green over your right) to get the dramatic 3D perspective. The stereo view was recorded by the remarkable Imager for Mars Pathfinder (IMP) camera. The IMP has two optical paths for stereo imaging and ranging and is equipped with an array of color filters for spectral analysis. Operating as the "first astronomical observatory on Mars" the IMP has also recorded images of the Sun and Deimos, the smallest of Mars' two tiny moons. Overcoming communications problems and computer resets the Pathfinder is transmitting new color images which should be available July 18.

APOD: July 14, 1997 - Mars: Twin Peaks In Stereo
Explanation: Get out your red/blue glasses and gaze across the surface of Mars in stereo. You are looking south of west across an ancient flood channel, Ares Vallis, landing site of the Mars Pathfinder. A rover deployment ramp and lander petal define the foreground in this 3D-view while a field of rocks seems to stretch to the horizon. At the upper right, over half a mile distant, are the hills known as the "Twin Peaks". Today is Sol 10, the tenth day the Pathfinder lander and Sojourner rover have been operating on the martian surface. Over that period, the mission has been returning a wealth of images and data. The otherwise successful rover activities have been recently hampered by some communication and computer difficulties.

APOD: July 5, 1997 - Pathfinder on Mars
Explanation: Yesterday, July 4th, using its own array of fireworks, a parachute, and a cocoon of airbags, the Mars Pathfinder spacecraft successfully bounced and came to rest on the surface of Mars at 10:07 AM Pacific Daylight Time. And the news is wonderful - the spacecraft appears to be in good health after having performed its complicated landing sequence superbly. Above is a mosaic of images from the martian surface transmitted shortly after Pathfinder reestablished communication with its mission operators on Earth. The solar powered, two foot long, 25 pound Mars Sojourner robot rover is visible crouched on the unfolded spacecraft. Surrounding Pathfinder are deflated airbags and a rock-strewn terrain. In the distance martian hills appear against a dusty brownish sky. The IMP camera which produced this view is also capable of stereo images and promises further spectacular pictures from Mars.

APOD: April 4, 1997 - Hale-Bopp in Stereo
Explanation: This stereo pair of Hale-Bopp images combines two pictures from slightly different viewing angles. Simulating stereo vision, the difference was generated by the comet's apparent motion as it cruised through the inner Solar System. The camera was located in the Shoshone National Forest, Wyoming, USA, Planet Earth, and the two pictures were taken about 45 minutes apart on March 25. Digitized versions were then carefully cropped and adjusted so that the background stars matched. The product of an internet collaboration between J. Modjallal and M. Frost, this pair is meant to be viewed from a comfortable distance by gently crossing your eyes until the images merge.

APOD: January 12, 1997 - Mercury in Stereo: Craters Within Craters
Explanation: This Stereo image pair of craters on on Mercury was produced using data from NASA's robot explorer Mariner 10 which performed three close flybys of the Sun's closest companion, two in 1974 and one in 1975. However, the spacecraft was not equipped with a Stereo camera! Instead, the Stereo pair was created using two images of the same region each recorded from a slightly different angle. The image on the left was actually taken during the first flyby, the one on the right during the second. A crater within a crater is visible at the upper left, the outer one is about 70 miles in diameter. The embedded craters themselves are within the 230 mile wide Dostoevsky crater - a segment of Dostoevsky's rim runs through the lower half of the image. To get the 3D Stereo effect, your left eye should see only the left image and your right eye only the right one. (Try placing one edge of a piece of paper on the screen between the pictures and touching your nose to the other edge while viewing.)

APOD: December 23, 1996 - The Hills of Ganymede
Explanation: This computer generated 3D close-up view of Jupiter's large moon Ganymede was created using image data from NASA's Galileo spacecraft. Simulating stereo vision by combining two recent images recorded from different angles, 3 dimensional information was reconstructed for a section of Ganymede's surface. The result shows the furrows, craters, and hills in the region appropriately known as "Galileo Regio" with a resolution of about 250 feet. Currently exploring the Jovian System, the Galileo spacecraft just completed a flyby of Europa. It is scheduled to return to Ganymede in April next year.