A starry sky, with a bright column due to zodiacal light, illuminates the desert landscape around Cerro Paranal, home to ESO's Very Large Telescope (VLT).
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Does Earth have a dust build-up problem?
Estimates vary of how much cosmic dust and meteorites enter Earth’s atmosphere each day, but range anywhere from 5 to 300 metric tons, with estimates made from satellite data and extrapolations of meteorite falls. Thing is, no one really knows for sure and so far there hasn’t been any real coordinated efforts to find out. But a new project proposal called Cosmic Dust in the Terrestrial Atmosphere (CODITA) would provide more accurate estimates of how much material hits Earth, as well as how it might affect the atmosphere.
“We have a conundrum – estimates of how much dust comes in vary by a factor of a hundred,” said John Plane from University of Leeds in the UK. “The aim of CODITA is to resolve this huge discrepancy.”
Even though we consider space to be empty, if all the material between the Sun and Jupiter were compressed together it would form a moon 25 km across.
So how much of this stuff – leftovers from the formation of the planets, debris from comets and asteroid collisions, etc. — encounters Earth? Satellite observations suggest that 100-300 metric tons of cosmic dust enter the atmosphere each day. This figure comes from the rate of accumulation in polar ice cores and deep-sea sediments of rare elements linked to cosmic dust, such as iridium and osmium.
But other measurements – which includes meteor radar observations, laser observations and measurements by high altitude aircraft — indicate that the input could be as low as 5 metric ton per day.
Knowing the difference could have a big influence on our understanding of things like climate change and, noctilucent clouds, as well as ozone and ocean chemistry.
“If the dust input is around 200 tons per day, then the particles are being transported down through the middle atmosphere considerably faster than generally believed,” said Plane. “If the 5-tonne figure is correct, we will need to revise substantially our understanding of how dust evolves in the Solar System and is transported from the middle atmosphere to the surface.”
When dust particles approach the Earth they enter the atmosphere at very high speeds, anything from 38,000 to 248,000 km/hour, depending on whether they are orbiting in the same direction or the opposite to the Earth’s motion around the Sun. The particles undergo very rapid heating through collisions with air molecules, reaching temperatures well in excess of 1,600 degrees Celsius. Particles with diameters greater than about 2 millimeters produce visible “shooting stars,” but most of the mass of dust particles entering the atmosphere is estimated to be much smaller than this, so can be detected only using specialized meteor radars.
The metals injected into the atmosphere from evaporating dust particles are involved in a diverse range of phenomena linked to climate change.
“Cosmic dust is associated with the formation of ‘noctilucent’ clouds – the highest clouds in the Earth’s atmosphere. The dust particles provide a surface for the cloud’s ice crystals to form. These clouds develop during summer in the polar regions and they appear to be an indicator of climate change,’ said Plane. “The metals from the dust also affect ozone chemistry in the stratosphere. The amount of dust present will be important for any geo-engineering initiatives to increase sulphate aerosol to offset global warming. Cosmic dust also fertilises the ocean with iron, which has potential climate feedbacks because marine phytoplankton emit climate-related gases.”
The CODITA team will also use laboratory facilities to tackle some of the least well-understood aspects of the problem
“In the lab, we’ll be looking at the nature of cosmic dust evaporation, as well as the formation of meteoric smoke particles, which play a role in ice nucleation and the freezing of polar stratospheric clouds,” said Plane. “The results will be incorporated into a chemistry-climate model of the whole atmosphere. This will make it possible, for the first time, to model the effects of cosmic dust consistently from the outer Solar System to the Earth’s surface.”
CODITA has received a EUR 2.5 million grant from the European Research Council to investigate the dust input over the next 5 years. The international team, led by Plane, is made up of over 20 scientists in the UK, the US and Germany. Plane presented information about the project at the National Astronomy meeting in the UK this week.
The Orion Exploration Flight Test-1 (EFT-1) is scheduled to launch the first unmanned Orion crew cabin into a high altitude Earth orbit in 2014 atop a Delta 4 Heavy rocket from Cape Canaveral, Florida. Artist’s concept. Credit: NASA
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NASA is on course to make the highest leap in human spaceflight in nearly 4 decades when an unmanned Orion crew capsule blasts off from Cape Canaveral, Fla., on a high stakes, high altitude test flight in early 2014.
A new narrated animation (see below) released by NASA depicts the planned 2014 launch of the Orion spacecraft on the Exploration Flight Test-1 (EFT-1) mission to the highest altitude orbit reached by a spaceship intended for humans since the Apollo Moon landing Era.
Orion is NASA’s next generation human rated spacecraft and designed for missions to again take humans to destinations beyond low Earth orbit- to the Moon, Mars, Asteroids and Beyond to deep space.
Orion Video Caption – Orion: Exploration Flight Test-1 Animation (with narration by Jay Estes). This animation depicts the proposed test flight of the Orion spacecraft in 2014. Narration by Jay Estes, Deputy for flight test integration in the Orion program.
Lockheed Martin Space Systems is making steady progress constructing the Orion crew cabin that will launch atop a Delta 4 Heavy booster rocket on a two orbit test flight to an altitude of more than 3,600 miles and test the majority of Orion’s vital vehicle systems.
The capsule will then separate from the upper stage, re-enter Earth’s atmosphere at a speed exceeding 20,000 MPH, deploy a trio of huge parachutes and splashdown in the Pacific Ocean off the west coast of California.
Lockheed Martin is responsible for conducting the critical EFT-1 flight under contract to NASA.
Orion will reach an altitude 15 times higher than the International Space Station (ISS) circling in low orbit some 250 miles above Earth and provide highly valuable in-flight engineering data that will be crucial for continued development of the spaceship.
Orion Exploration Flight Test One Overview. Credit: NASA
“This flight test is a challenge. It will be difficult. We have a lot of confidence in our design, but we are certain that we will find out things we do not know,” said NASA’s Orion Program Manager Mark Geyer.
“Having the opportunity to do that early in our development is invaluable, because it will allow us to make adjustments now and address them much more efficiently than if we find changes are needed later. Our measure of success for this test will be in how we apply all of those lessons as we move forward.”
Lockheed Martin is nearing completion of the initial assembly of the Orion EFT-1 capsule at NASA’s historic Michoud Assembly Facility (MAF) in New Orleans, which for three decades built all of the huge External Fuel Tanks for the NASA’s Space Shuttle program.
In May, the Orion will be shipped to the Kennedy Space Center in Florida for final assembly and eventual integration atop the Delta 4 Heavy rocket booster and launch from Space Launch Complex 37 at nearby Cape Canaveral. The Delta 4 is built by United Launch Alliance.
The first integrated launch of an uncrewed Orion is scheduled for 2017 on the first flight of NASA’s new heavy lift rocket, the SLS or Space Launch System that will replace the now retired Space Shuttle orbiters
Continued progress on Orion, the SLS and all other NASA programs – manned and unmanned – is fully dependent on the funding level of NASA’s budget which has been significantly slashed by political leaders of both parties in Washington, DC in recent years.
…….
March 24 (Sat): Free Lecture by Ken Kremer at the New Jersey Astronomical Association, Voorhees State Park, NJ at 830 PM. Topic: Atlantis, the End of Americas Shuttle Program, Orion, SpaceX, CST-100 and the Future of NASA Human & Robotic Spaceflight
Vesta imaged by NASA’s Dawn Asteroid Orbiter. Dawn is currently at work at the Low Altitude Mapping Orbit (LAMO) acquiring new imagery and spectra of much higher resolution compared to these images acquired at higher altitudes and is also filling in gaps of surface data. The image from Dawn’s Framing Camera, at left, was taken on July 24 at a distance of 3,200 miles soon after achieving orbit around Vesta. The mosaic from Dawn’s Visible and infrared spectrometer (VIR), at right, was acquired from High-altitude mapping orbit (HAMO). Credit: NASA/ JPL-Caltech/ UCLA/ ASI/ INAF/ IAPS. Collage: Ken Kremer
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NASA’s Dawn mission is getting a whopping boost in science observing time at the closest orbit around Asteroid Vesta as the probe passes the midway point of its 1 year long survey of the colossal space rock. And the team informs Universe Today that the data so far have surpassed all expectations and they are very excited !
Dawn’s bonus study time amounts to an additional 40 days circling Vesta at the highest resolution altitude for scientific measurements. That translates to a more than 50 percent increase beyond the originally planned length of 70 days at what is dubbed the Low Altitude Mapping Orbit, or LAMO.
“We are truly thrilled to be able to spend more time observing Vesta from low altitude,” Dr. Marc Rayman told Universe Today in an exclusive interview. Rayman is Dawn’s Engineer at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif.
“It is very exciting indeed to obtain such a close-up look at a world that even a year ago was still just a fuzzy blob.”
The big extension for a once-in-a-lifetime shot at up close science was all enabled owing to the hard work of the international science team in diligently handling any anomalies along the pathway through interplanetary space and since Dawn achieved orbit in July 2011, as well as to the innovative engineering of the spacecraft’s design and its revolutionary ion propulsion system.
“This is a reflection of how well all of our work at Vesta has gone from the beginning of the approach phase in May 2011,” Rayman told me.
Simulated view of Vesta from Dawn in LAMO, low altitude mapping orbit - March, 6 2012
Credit: Gregory J. Whiffen, JPL
Dawn’s initially projected 10 week long science campaign at LAMO began on Dec. 12, 2011 at an average distance of 210 kilometers (130 miles) from the protoplanet and was expected to conclude on Feb. 20, 2012 under the original timeline. Thereafter it would start spiraling back out to the High Altitude Mapping Orbit, known as HAMO, approximately 680 kilometers above the surface.
“With the additional 40 days it means we are now scheduled to leave LAMO on April 4. That’s when we begin ion thrusting for the transfer to HAMO2,” Rayman stated.
And the observations to date at LAMO have already vastly surpassed all hopes – using all three of the onboard science instruments provided by the US, Germany and Italy.
“Dawn’s productivity certainly is exceeding what we had expected,” exclaimed Rayman.
“We have acquired more than 7500 LAMO pictures from the Framing Camera and more than 1 million LAMO VIR (Visible and Infrared) spectra which afford scientists a much more detailed view of Vesta than had been planned with the survey orbit and the high altitude mapping orbit (HAMO). It would have been really neat just to have acquired even only a few of these close-up observations, but we have a great bounty!”
“Roughly around half of Vesta’s surface has been imaged at LAMO.”
Dawn mosaic of Visible and Infrared spectrometer (VIR) data of Vesta
This mosaic shows the location of the data acquired by VIR (visible and infrared spectrometer) during the HAMO (high-altitude mapping orbit) phase of the Dawn mission from August to October 2011. Dawn is now making the same observations at the now extended LAMO (low-altitude mapping orbit) phase of the Dawn mission from December 2011 to April 2012. VIR can image Vesta in a number of different wavelengths of light, ranging from the visible to the infrared part of the electromagnetic spectrum. This mosaic shows the images taken at a wavelength of 550 nanometers, which is in the visible part of the electromagnetic spectrum. During HAMO VIR obtained more than 4.6 million spectra of Vesta. It is clear from this image that the VIR observations are widely distributed across Vesta, which results in a global view of the spectral properties of Vesta’s surface. This image shows Vesta’s southern hemisphere (lower part of the image) and equatorial regions (upper part of the image). NASA’s Dawn spacecraft obtained these VIR images with its visible and infrared spectrometer in September and October 2011. The distance to the surface of Vesta is around 700 kilometers (435 miles) and the average image resolution is 170 meters per pixel. Credit: NASA/ JPL-Caltech/ UCLA/ ASI/ INAF/ IAPS
The bonus time at LAMO will now be effectively used to help fill in the gaps in surface coverage utilizing all 3 science instruments. Therefore perhaps an additional 20% to 25% extra territory will be imaged at the highest possible resolution. Some of this will surely amount to enlarged new coverage and some will be overlapping with prior terrain, which also has enormous research benefits.
“There is real value even in seeing the same part of the surface multiple times, because the illumination may be different. In addition, it helps for building up stereo,” said Rayman.
Researchers will deduce further critical facts about Vesta’s topography, composition, interior, gravity and geologic features with the supplemental measurements.
Successive formation of impact craters on Vesta
This Dawn FC (framing camera) image shows two overlapping impact craters and was taken on Dec. 18,2011 during the LAMO (low-altitude mapping orbit) phase of the mission. The large crater is roughly 20 kilometers (12 miles) in diameter and the smaller crater is roughly 6 kilometers (4 miles) in diameter. The rims of the craters are both reasonably fresh but the larger crater must be older because the smaller crater cuts across the larger crater’s rim. As the smaller crater formed it destroyed a part of the rim of the pre-existing, larger crater. The larger crater’s interior is more densely cratered than the smaller crater, which also suggests that is it older. In the bottom of the image there is some material slumping from rim of the larger crater towards its center. This image with its framing camera on Dec. 18, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 260 kilometers (162 miles) and the image has a resolution of about 22 meters (82 feet) per pixel. Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
The foremost science goals at LAMO are collection of gamma ray and neutron measurements with the GRaND instrument – which focuses on determining the elemental abundances of Vesta – and collection of information about the structure of the gravitational field. Since GRaND can only operate effectively at low orbit, the extended duration at LAMO takes on further significance.
“Our focus is on acquiring the highest priority science. The pointing of the spacecraft is determined by our primary scientific objectives of collecting GRaND and gravity measurements.”
As Dawn continues orbiting every 4.3 hours around Vesta during LAMO, GRaND is recording measurements of the subatomic particles that emanate from the surface as a result of the continuous bombardment of cosmic rays and reveals the signatures of the elements down to a depth of about 1 meter.
“You can think of GRaND as taking a picture of Vesta but in extremely faint light. That is, the nuclear emissions it detects are extremely weak. So our long time in LAMO is devoted to making a very, very long exposure, albeit in gamma rays and neutrons and not in visible light,” explained Rayman.
Now with the prolonged mission at LAMO the team can gather even more data, amounting to thousands and thousands more pictures, hundreds of thousands of more VIR spectra and ultra long exposures by GRaND.
“HAMO investigations have already produced global coverage of Vesta’s gravity field,” said Sami Asmar, a Dawn co-investigator from JPL. Extended investigations at LAMO will likewise vastly improve the results from the gravity experiment.
Dawn Spacecraft Current Location and Trajectory - March, 6 2012. Credit: Gregory J. Whiffen, JPL
“We always carried 40 days of “margin,” said Rayman, “but no one who was knowledgeable about the myriad challenges of exploring this uncharted world expected we would be able to accomplish all the complicated activities before LAMO without needing to consume some of that margin. So although we recognized that we might get to spend some additional time in LAMO, we certainly did not anticipate it would be so much.”
“As it turned out, although we did have surprises the operations team managed to recover from all of them without using any of those 40 days.”
“This is a wonderful bonus for science,” Rayman concluded.
“We remain on schedule to depart Vesta in July 2012, as planned for the past several years.”
Dawn’s next target is Ceres, the largest asteroid in the main Asteroid Belt between Mars and Jupiter
Lake Cuitzeo in central Mexico. (Via Julio Marquez, Wikipedia Commons)
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Exotic sediments found beneath the floor of Lake Cuitzeo in central Mexico support theories of a major cosmic impact event 12,900 years ago, report a 16-member international research team. The impact may have caused widespread environmental changes and contributed to the extinctions of many large animal species.
Images of single and twinned nanodiamonds show the atomic lattice framework of the nanodiamonds. Each dot represents a single atom. (Source: UCSB release.)
The team found a 13,000-year-old layer of sediment that contains materials associated with impact events, such as soot, impact spherules and atomic-scale structures known as nanodiamonds. The nanodiamonds found at Lake Cuitzeo are of a variety known as lonsdaleite, even harder than “regular” diamond and only found naturally as the result of impact events.
The thin layer of sediment below Cuitzeo corresponds to layers of similar age found throughout North America, Greenland and Western Europe.
It’s thought that a large several-hundred-meter-wide asteroid or comet entered Earth’s atmosphere at a shallow angle 12,900 years ago, melting rocks, burning biomass and, in general, causing widespread chaos and destruction. This hypothesized event would have occurred just before a period of unusually cold climate known as the Younger Dryas.
The Younger Dryas has been associated with the extinction of large North American animals such as mammoths, saber-tooth cats and dire wolves.
“The timing of the impact event coincided with the most extraordinary biotic and environmental changes over Mexico and Central America during the last approximately 20,000 years, as recorded by others in several regional lake deposits,” said James Kennett, professor of earth science at UC Santa Barbara and member of the research team. “These changes were large, abrupt, and unprecedented, and had been recorded and identified by earlier investigators as a ‘time of crisis.’ ”
The exotic materials found in the sediment beneath Cuitzeo could not have been created by any volcanic, terrestrial or man-made process. “These materials form only through cosmic impact,” Kennett said.
The only other widespread sedimentary layer ever found to contain such an abundance of nanodiamonds and soot is found at the K-T boundary, 65 million years ago. This, of course, corresponds to the impact event that led to the extinction of the dinosaurs.
The researchers’ findings appeared March 5 in the Proceedings of the National Academy of Sciences. Read the news release from UC Santa Barbara here.
A large meteor seen in the sky over the UK, near a rainbow light display. Credit: Mike Ridley.
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On the evening of March 3rd 2012 at approximately 21:40 GMT, an incredibly bright fireball/bollide was seen over the United kingdom.
Many people were outside enjoying a clear evening under the stars, or going about their ordinary business when they spotted the amazingly bright object shooting across the sky. Nearly all of the observations from the public from across much of the country described the object as a very bright fireball traveling from north to south and disappearing low in the sky.
The image above is from Mike Ridley, who said, “I was out tonight photographing the global rainbow display at Whitly Bay and saw this bright light hurtling across the sky. I quickly turned the camera to capture it as it flew overhead. With the naked eye I could see it white hot with an orange tail & really low in the sky. I thought it was a massive firework rocket.”
See two videos of the fireball, below.
Most accounts give a duration of around 10 to 15 seconds and the fireball showed a bright orange nucleus with a bright green tail. There was some fragmentation as the fireball ploughed through the atmosphere.
At present, it is unknown whether any pieces of the object survived and hit Earth’s surface, but there is a high possibility that if it did, it landed in the ocean.
The orbit of asteroid 2011 AG5 carries it beyond the orbit of Mars and as close to the sun as halfway between Earth and Venus. Image credit: NASA/JPL/Caltech/NEOPO
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You may have heard about an asteroid in the news this week that has a 1 in 625 chance of hitting Earth on Feb. 5, 2040. So, will this asteroid, named 2011 AG5, really hit our planet? The quick answer is, probably not. But astronomers will need more observations of this asteroid to say one way or the other for sure.
“Because of the extreme rarity of an impact by a near-Earth asteroid of this size, I fully expect we will be able to significantly reduce or rule out entirely any impact probability for the foreseeable future,” said Donald Yeomans, head of the Near-Earth Object Observations Program at NASA’s Jet Propulsion Laboratory.
Yeomans classified the chance of impact as “unlikely” and here are some facts that we do know about Asteroid about 2011 AG5:
What is the potential that this asteroid will impact Earth?
Currently astronomers have this asteroid ranked as a “1” on the 1 to 10 Torino Impact Hazard Scale. A “1” means this asteroid will have a pass near the Earth that poses no unusual level of danger. Current calculations show the chance of collision is extremely unlikely with no cause for public attention or public concern. Very likely, subsequent telescopic observations will lead to re-assignment to Level 0. The 1 in 625 chance is what the predictions are for the data that NASA has right now. Further observations will likely decrease the odds, and may even bring it to zero.
How big is this asteroid?
2011 AG5 is a 140-meter-wide (460 feet) space rock. Its composition is not yet known – whether it is a rocky, iron or icy asteroid.
How many Near Earth asteroids are out there?
Asteroid 2011 AG5 is one of 8,744 near-Earth objects that have been discovered so far, as of this week (March 1, 2012). NEOs are objects that come within 1.3 AU of the Sun (with Earth at 1 AU, so it means they pass through our neighborhood.)
1,305 of these NEOs have been classified as Potentially Hazardous Asteroids (PHAs), which are those that are larger than about 150 m (500 ft) and come within 0.05 AU of Earth’s orbit, so 2011 AG5 is right at the edge of that classification.
How was this asteroid discovered?
It was discovered on Jan. 8, 2011, by astronomers using a 60-inch Cassegrain reflector telescope located at the summit of Mount Lemmon in the Catalina Mountains north of Tucson, Arizona.
Where is 2011 AG5 now?
Its orbit carries it as far out as beyond Mars’ orbit and as close to the Sun as halfway between Earth and Venus. See the image above for its approximate current location. Its proximity to the Sun from our vantage point on Earth means astronomers can’t make observations right now.
When will astronomers find out more and be able to make better predictions?
“In September 2013, we have the opportunity to make additional observations of 2011 AG5 when it comes within 91 million miles (147 million kilometers) of Earth,” said Yeomans. “It will be an opportunity to observe this space rock and further refine its orbit.”
Yeomans added that even better observations will be possible in late 2015.
Will this asteroid come close to Earth before 2040?
2011 AG5 will next be near Earth in February of 2023 when it will pass the planet no closer than about 1.2 million miles (1.9 million kilometers). In 2028, the asteroid will again be in the area, coming no closer than about 12.8 million miles (20.6 million kilometers). The Near-Earth Object Program Office says the Earth’s gravitational influence on the space rock during these flybys has the potential to place the space rock on an impact course for Feb. 5, 2040, but this has very unlikely odds of occurring at 1-in-625.
“Again, it is important to note that with additional observations next year the odds will change and we expect them to change in Earth’s favor,” said Yeomans.
Screenshot from the Impact Earth website animation.
If Asteroid 2011 AG5 were to hit Earth, what is the potential for damage to Earth?
According to calculations from the Impact Earth website, an object of this size would begin to break up in Earth’s atmosphere at an altitude of 65500 meters (215,000 ft). Some of the larger pieces would reach the ground, with the pieces hitting Earth’s surface (ground) at a velocity Of 2.64 km/s (1.64 miles/s). The impact energy would be 7.52 x 10^15 Joules, or 1.8 MegaTons.
This would not cause any global problems, as the planet as a whole would not be strongly disturbed by the impact.
The broken projectile fragments would strike the ground in an ellipse about 1.17 km by 0.824 km in diameter, and the result of the impact is a crater field, not a single crater. The largest crater would be about 400 meters in diameter (1,310 feet). The impact would create a Richter Scale Magnitude-like event of 4.8.
If you were 1-10 km away from the impact area, you would feel a sensation like a heavy truck striking building. Standing cars would be rocked noticeably. Indoors, dishes and windows, might be disturbed and walls might make a cracking sound. An air blast at speeds of 26.3 m/s = 58.9 mph would arrive approximately 10 – 30 seconds after impact.
If this impactor hit in an ocean, the impact-generated tsunami wave would arrive approximately 6.18 minutes after impact if you were 10 km away, with a wave amplitude is between: 4.78 and 9.55 meters (15.7 feet and 31.3 feet).
How often do asteroids hit the Earth?
Yeomans said that every day, Earth is pummeled by more than 100 tons of material that spewed off asteroids and comets. Fortunately the vast majority of this “spillover” is just dust and very small particles. “We sometimes see these sand-sized particles brighten the sky, creating meteors, or shooting stars, as they burn up upon entry into Earth’s atmosphere,” Yeomans said in his “Top Ten Asteroid Factoids” article. “Roughly once a day, a basketball-sized object strikes Earth’s atmosphere and burns up. A few times each year, a fragment the size of a small car hits Earth’s atmosphere. These larger fragments cause impressive fireballs as they burn through the atmosphere. Very rarely, sizable fragments survive their fiery passage through Earth’s atmosphere and hit the surface, becoming meteorites.”
The Faulkes Telescope. Credit: Faulkes Telescope/LCOGT
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Using and getting the most out of robotic astronomy
Whilst nothing in the field of amateur astronomy beats the feeling of being outside looking up at the stars, the inclement weather many of us have to face at various times of year, combined with the task of setting up and then packing away equipment on a nightly basis, can be a drag. Those of us fortunate enough to have observatories don’t face that latter issue, but still face the weather and usually the limits of our own equipment and skies.
Another option to consider is using a robotic telescope. From the comfort of your home you can make incredible observations, take outstanding astrophotos, and even make key contributions to science!
The main elements which make robotic telescopes appealing to many amateur astronomers are based around 3 factors. The first is that usually, the equipment being offered is generally vastly superior to that which the amateur has in their home observatory. Many of the robotic commercial telescope systems, have large format mono CCD cameras, connected to high precision computer controlled mounts, with superb optics on top, typically these setups start in the $20-$30,000 price bracket and can run up in to the millions of dollars.
A look at the Faulkes Telescope South inside. Credit: Faulkes Telescope/LCOGT
Combined with usually well defined and fluid workflow processes which guide even a novice user through the use of the scope and then acquisition of images, automatically handling such things as dark and flat fields, makes it a much easier learning curve for many as well, with many of the scopes specifically geared for early grade school students.
Screenshot of the Faulkes Telescope realtime interface. Credit: Faulkes Telescope/LCOGT
The second factor is geographic location. Many of the robotic sites are located in places where average rainfall is a lot lower than say somewhere like the UK or North Eastern United States for example, with places like New Mexico and Chile in particular offering almost completely clear dry skies year round. Robotic scopes tend to see more sky than most amateur setups, and as they are being controlled over the Internet, you yourself don’t even have to get cold outside in the depths of winter. The beauty of the geographic location aspect is that in some cases, you can do your astronomy during the daytime, as the scopes may be on the other side of the world.
iTelescope systems are located all over the globe. Credit: iTelescope project
The third is ease of use, as it’s nothing more than a reasonably decent laptop, and solid broadband connection that’s required. The only thing you need worry about is your internet connection dropping, not your equipment failing to work. With scopes like the Faulkes or Liverpool Telescopes, ones I use a lot, they can be controlled from something as modest as a netbook or even an Android/iPad/iPhone, easily. The issues with CPU horsepower usually comes down to the image processing after you have taken your pictures.
Software applications like the brilliant Maxim DL by Diffraction Limited which is commonly used for image post processing in amateur and even professional astronomy, handles the FITS file data which robotic scopes will deliver. This is commonly the format images are saved in with professional observatories, and the same applies with many home amateur setups and robotic telescopes. This software requires a reasonably fast PC to work efficiently, as does the other stalwart of the imaging community, Adobe Photoshop. There are some superb and free applications which can be used instead of these two bastions of the imaging fraternity, like the excellent Deep Sky stacker, and IRIS, along with the interestingly named “GIMP” which is variant on the Photoshop theme, but free to use.
Some people may say just handling image data or a telescope over the internet detracts from real astronomy, but it’s how professional astronomers work day in day out, usually just doing data reduction from telescopes located on the other side of the world. Professionals can wait years to get telescope time, and even then rather than actually being a part of the imaging process, will submit imaging runs to observatories, and wait for the data to roll in. (If anyone wants to argue this fact…just say “Try doing eyepiece astronomy with the Hubble”)
The process of using and imaging with a robotic telescope still requires a level of skill and dedication to guarantee a good night of observing, be it for pretty pictures or real science or both.
Location Location Location
The location for a robotic telescope is critical as if you want to image some of the wonders of the Southern Hemisphere, which those of us in the UK or North America will never see from home, then you’ll need to pick a suitably located scope. Time of day is also important for access, unless the scope system allows an offline queue management approach, whereby you schedule it to do your observations for you and just wait for the results. Some telescopes utilise a real time interface, where you literally control the scope live from your computer, typically through a web browser interface. So depending on where in the world it is, you may be in work, or it may be at a very unhealthy hour in the night before you can access your telescope, it’s worth considering this when you decide which robotic system you wish to be a part of.
Telescopes like the twin Faulkes 2-metre scopes, which are based on the Hawaiian island of Maui, atop a mountain, and Siding Spring, Australia, next to the world famous Anglo Australian Observatory, operate during usual school hours in the UK, which means night time in the locations where the scopes live. This is perfect for children in western Europe who wish to use research grade professional technology from the classroom, though the Faulkes scopes are also used by schools and researchers in Hawaii.
The type of scope/camera you choose to use, will ultimately also determine what it is you image. Some robotic scopes are configured with wide field large format CCD’s connected to fast, low focal ratio telescopes. These are perfect for creating large sky vistas encompassing nebulae and larger galaxies like Messier 31 in Andromeda. For imaging competitions like the Astronomy Photographer of the Year competition, these wide field scopes are perfect for the beautiful skyscapes they can create.
Scopes like the Faulkes Telescope North, even though it has a huge 2m (almost the same size as the one on the Hubble Space Telescope) mirror, is configured for smaller fields of view, literally only around 10 arcminutes, which will nicely fit in objects like Messier 51, the Whirpool Galaxy, but would take many separate images to image something like the full Moon (If Faulkes North were set up for that, which it’s not). It’s advantage is aperture size and immense CCD sensitivity. Typically our team using them is able to image a magnitude +23 moving object (comet or asteroid) in under a minute using a red filter too!
A field of view with a scope like the twin Faulkes scopes, which are owned and operated byLCOGT is perfect for smaller deep sky objects and my own interests which are comets and asteroids.Many other research projects such as exoplanets and the study of variable stars are conducted using these telescopes.Many schools start out imaging nebulae, smaller galaxies and globular clusters, with our aim at the Faulkes Telescope Project office, to quickly get students moving on to more science based work, whilst keeping it fun. For imagers, mosaic approaches are possible to create larger fields, but this obviously will take up more imaging and telescope slew time.
Each robotic system has its own set of learning curves, and each can suffer from technical or weather related difficulties, like any complex piece of machinery or electronic system. Knowing a bit about the imaging process to begin with, sitting in on other’s observing sessions on things like Slooh, all helps. Also make sure you know your target field of view/size on the sky (usually in either right ascension and declination) or some systems have a “guided tour mode” with named objects, and make sure you can be ready to move the scope to it as quickly as possible, to get imaging. With the commercial robotic scopes, time really is money.
Global Rent-A-Scope interface
Magazines like Astronomy Now in the UK, as well as Astronomy and Sky and Telescope in the United States and Australia are excellent resources for finding out more, as they regularly feature robotic imaging and scopes in their articles. Online forums like cloudynights.com and stargazerslounge.com also have thousands of active members, many of whom regularly use robotic scopes and can give advice on imaging and use, and there are dedicated groups for robotic astronomy like the Online Astronomical Society. Search engines will also give useful information on what is available as well.
To get access to them, most of the robotic scopes require a simple sign up process, and then the user can either have limited free access, which is usually an introductory offer, or just start to pay for time. The scopes come in various sizes and quality of camera, the better they are, usually the more you pay. For education and school users as well as astronomical societies, The Faulkes Telescope (for schools) and the Bradford Robotic scope both offer free access, as does the NASA funded Micro Observatory project. Commercial ones like iTelescope, Slooh and Lightbuckets provide a range of telescopes and imaging options, with a wide variety of price models from casual to research grade instrumentation and facilities.
So what about my own use of Robotic Telescopes?
Personally I use mainly the Faulkes North and South scopes, as well as the Liverpool La Palma Telescope. I have worked with the Faulkes Telescope Project team now for a few years, and it’s a real honour to have such access to research grade intrumentation. Our team also use the iTelescope network when objects are difficult to obtain using the Faulkes or Liverpool scopes, though with smaller apertures, we’re more limited in our target choice when it comes to very faint asteroid or comet type objects.
After having been invited to meetings in an advisory capacity for Faulkes, late in 2011 I was appointed pro am program manager, co-ordinating projects with amateurs and other research groups. With regards to public outreach I have presented my work at conferences and public outreach events for Faulkes and we’re about to embark on a new and exciting project with the European Space Agency whom I work for also as a science writer.
My use of Faulkes and the Liverpool scopes is primarily for comet recovery, measurement (dust/coma photometry and embarking on spectroscopy) and detection work, those icy solar system interlopers being my key interest. In this area, I co-discovered Comet C2007/Q3 splitting in 2010, and worked closely with the amateur observing program managed by NASA for comet 103P, where my images were featured in National Geographic, The Times, BBC Television and also used by NASA at their press conference for the 103P pre-encounter event at JPL.
The 2m mirrors have huge light grasp, and can reach very faint magnitudes in very little time. When attempting to find new comets or recover orbits on existing ones, being able to image a moving target at magnitude 23 in under 30s is a real boon. I am also fortunate to work alongside two exceptional people in Italy, Giovanni Sostero and Ernesto Guido, and we maintain a blog of our work, and I am a part of the CARA research group working on comet coma and dust measurements, with our work in professional research papers such as the Astrophysical Journal Letters and Icarus.
The Imaging Process
When taking the image itself, the process starts really before you have access to the scope. Knowing the field of view, what it is you want to achieve is critical, as is knowing the capabilities of the scope and camera in question, and importantly, whether or not the object you want to image is visible from the location/time you’ll be using it.
First thing I would do if starting out again is look through the archives of the telescope, which are usually freely available, and see what others have imaged, how they have imaged in terms of filters, exposure times etc, and then match that against your own targets.
Ideally, given that in many cases, time will be costly, make sure that if you’re aiming for a faint deep sky object with tenuous nebulosity, you don’t pick a night with a bright Moon in the sky, even with narrowband filters, this can hamper the final image quality, and that your choice of scope/camera will in fact image what you want it to. Remember that others may also want to use the same telescopes, so plan ahead and book early. When the Moon is bright, many of the commercial robotic scope vendors offer discounted rates, which is great if you’re imaging something like globular clusters maybe, which aren’t as affected by the moonlight (as say a nebula would be)
Forward planning is usually essential, knowing that your object is visible and not too close to any horizon limits which the scope may impose, ideally picking objects as high up as possible, or rising to give you plenty of imaging time. Once that’s all done, then following the scope’s imaging process depends on which one you choose, but with something like Faulkes, it’s as simple as selecting the target/FOV, slewing the scope, setting the filter, and then exposure time and then waiting for the image to come in.
The number of shots taken depends on the time you have. Usually when imaging a comet using Faulkes I will try to take between 10 and 15 images to detect the motion, and give me enough good signal for the scientific data reduction which follows. Always remember though, that you’re usually working with vastly superior equipment than you have at home, and the time it takes to image an object using your home setup will be a lot less with a 2m telescope. A good example is that a full colour high resolution image of something like the Eagle Nebula can be obtained in a matter of minutes on Faulkes, in narrowband, something which would usually take hours on a typical backyard telescope.
For imaging a non moving target, the more shots in full colour or with your chosen filter (Hydrogen Alpha being a commonly used one with Faulkes for nebula) you can get the better. When imaging in colour, the three filters on the telescope itself are grouped into an RGB set, so you don’t need to set up each colour band. I’d usually add a luminance layer with H-Alpha if it’s an emission nebula, or maybe a few more red images if it’s not for luminance. Once the imaging run is complete, the data is usually placed on a server for you to collect, and then after downloading the FITS files, combine the images using Maxim (or other suitable software) and then on in to something like Photoshop to make the final colour image. The more images you take, the better the quality of the signal against the background noise, and hence a smoother and more polished final shot.
Between shots the only thing that will usually change will be filters, unless tracking a moving target, and possibly the exposure time, as some filters take less time to get the requisite amount of light. For example with a H-Alpha/OIII/SII image, you typically image for a lot longer with SII as the emission with many objects is weaker in this band, whereas many deep sky nebula emit strongly in the H-Alpha.
The Image Itself
NGC 6302 taken by Thomas Mills High School with the Faulkes Telescope
As with any imaging of deep sky objects, don’t be afraid to throw away poor quality sub frames (the shorter exposures which go to make up the final long exposure when stacked). These could be affected by cloud, satellite trails or any number of factors, such as the autoguider on the telescope not working correctly. Keep the good shots, and use those to get as good a RAW stacked data frame as you can. Then it’s all down to post processing tools in products like Maxim/Photoshop/Gimp, where you’d adjust the colours, levels, curves and possibly use plug ins to sharpen up the focus, or reduce noise. If it’s pure science your interested in, you’ll probably skip most of those steps and just want good, calibrated image data (dark and flat field subtracted as well as bias)
The processing side is very important when taking shots for aesthetic value, it seems obvious, but many people can overdo it with image processing, lessening the impact and/or value of the original data. Usually most amateur imagers spend more time on processing than actual imaging, but this does vary, it can be from hours to literally days doing tweaks. Typically when processing an image taken robotically, the dark and flat field calibration are done. First thing I do is access the datasets as FITS files, and bring those in to Maxim DL. Here I will combine and adjust the histogram on the image, possible running multiple iterations of a de-convolution algorithm if the start points are not as tight (maybe due to seeing issues that night).
Once the images are tightened up and then stretched, I will save them out as FITS files, and using the free FITS Liberator application bring them in to Photoshop. Here, additional noise reduction and contrast/level and curve adjustments will be made on each channel, running a set of actions known as Noels actions (a suite of superb actions by Noel Carboni, one of the worlds foremost imaging experts) can also enhance the final individual red green and blue channels (and the combined colour one).
Then, I will composite the images using layers into a colour final shot, adjusting this for colour balance and contrast. Possibly running a focus enhancement plug in and further noise reduction. Then publish them via flickr/facebook/twitter and/or submit to magazines/journals or scientific research papers depending on the final aim/goals.
Serendipity can be a wonderful thing
I got in to this quite by accident myself…. In March 2010, I had seen a posting on a newsgroup that Comet C/2007 Q3, a magnitude 12-14 object at the time, was passing near to a galaxy, and would make an interesting wide field side by side shot. That weekend, using my own observatory, I imaged the comet over several nights, and noticed a distinct change in the tail and brightness of the comet over two nights in particular.
Comet C/2007 Q3. Credit: Nick Howes
A member of the BAA (British Astronomical Association), seeing my images, then asked if I would submit them for publication. I decided however to investigate this brightening a bit further, and as I had access to the Faulkes that week, decided to point the 2m scope at this comet, to see if anything unusual was taking place. The first images came in, and I immediately, after loading them in to Maxim DL and adjusting the histogram, noticed that a small fuzzy blob appeared to be tracking the comet’s movement just behind it. I measured the separation as only a few arc-seconds, and after staring at it for a few minutes, decided that it may have fragmented.
I contacted Faulkes Telescope control, who put me in touch with the BAA comet section director, who kindly logged this observation the same day. I then contacted Astronomy Now magazine, who leapt on the story and images and immediately went to press with it on their website. The following days the media furore was quite literally incredible.
Interviews with national newspapers, BBC Radio, Coverage on the BBC’s Sky at Night television show, Discovery Channel, Radio Hawaii, Ethiopia were just a few of the news/media outlets that picked up the story.. the news went global that an amateur had made a major astronomical discovery from his desk using a robotic scope. This then led on to me working with members of the AOP project with the NASA/University of Maryland EPOXI mission team on imaging and obtaining light curve data for comet 103P late in 2010, again which led to articles and images in National Geographic, The Times and even my images used by NASA in their press briefings, alongside images from the Hubble Space Telescope. Subscription requests to Faulkes Telescope Project as a result of my discoveries went up by hundreds of % from all over the world.
In summary
Robotic telescopes can be fun, they can lead to amazing things, this past year, a work experience student I was mentor for with the Faulkes Telescope Project, imaged several fields we’d assigned to her, where our team then found dozens of new and un-catalogued asteroids, and she also managed to image a comet fragmenting. Taking pretty pictures is fun, but the buzz for me comes with the real scientific research I am now engaged in, and it’s a pathway I aim to stay on probably for the rest of my astronomical lifetime. For students and people who don’t have the ability to either own a telescope due to financial or possibly location constraints, it’s a fantastic way to do real astronomy, using real equipment, and I hope, in reading this, you’re encouraged to give these fantastic robotic telescopes a try.
Vesta's surface textures get highlighted by dawn's light
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Sunrise on Vesta highlights the asteroid’s varied surface textures in this image from NASA’s Dawn spacecraft, released on Monday, Feb. 20. The image was taken on Dec. 18 with Dawn’s Framing Camera (FC).
Just as the low angle of early morning sunlight casts long shadows on Earth, sunrise on Vesta has the same effect — although on Vesta it’s not trees and buildings that are being illuminated but rather deep craters and chains of pits!
The steep inner wall of a crater is seen at lower right with several landslides visible, its outer ridge cutting a sharp line.
Chains of pits are visible in the center of the view. These features are the result of ejected material from an impact that occurred outside of the image area.
Other lower-profile, likely older craters remain in shadow.
Many of these features would appear much less dramatic with a high angle of illumination, but they really shine brightest in dawn’s light.
What an asteroid hitting the Earth might look like. Image credit: NASA/Don Davis.
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Scientists aren’t entirely sure when the last major asteroid hit the Earth, but it’s certain to happen again. Alan Harris, asteroid researcher at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), is hoping to head the next one off. Last month, Harris established an international collaboration of 13 researchers to investigate methods of shielding the Earth from near Earth objects (NEOs). The project is, appropriately, called NEOShield.
Asteroids approaching the planet typically travel between 5 and 30 kilometres (about 5 to 19 miles) per second. As that speed, a moderate sized body can have major consequences. The Barringer Crater in Arizona, often referred to as Meteor Crater, is a 1,200 metre crater (about 3,950 feet or 0.7 miles) that scientists hypothesize was caused by a 50 metre (164 feet) meteor.
The bad news is that there are thousands of known NEOs just like the one that made Meteor Crater, leading experts to posit that a dangerous collision could occur as often as every two hundred years.
Meteor Crater near Winslow, Arizona. Image credit: NASA.
The good news is that it’s possible to stop an asteroid hitting the Earth. You just have to be in the right place at the right time to give the object the right push in another direction.
Scientists are focusing on possible methods of redirecting threatening asteroids so they miss the Earth. “In order to modify their orbit and prevent a collision with Earth, a force must be exerted on them,” explains Alan Harris. “And at the precise time, as well.” One way to do this is to have a spacecraft impact a threatening asteroid, imparting enough force to change its orbit. “In my opinion, this is a very practical method,” said Harris. But there are still questions to answer, like how to guide the spacecraft to a moving target at the right angle for the right impact and how to minimize the effects of fuel movement on the spacecraft’s path.
Another way is to use the spacecraft’s gravitational pull to nudge the asteroid into a different orbit. If the object is far enough away, a tiny tug could have a big effect. But so far, “this method only exists on paper,” said Harris, “but it could work.”
An asteroid, docile in space but deadly to Earth. Image credit: NASA/JPL
Another third, less appealing prospect, is to use explosive power to break up an Earth-bound asteroid. But this could be disastrous, creating a shower of debris instead of one solid piece. As such, Harris considers this method a last resort. “If a very large, dangerous object with a diameter of one kilometre [0.6 miles] or more is discovered,” explains Harris, changing its orbit won’t be a option. “The greatest force we would be able to use to divert the asteroid from its path would be a nuclear explosion. This technique is regarded as a very controversial.”
Over the next three years, during which the European Union will support the project with four million Euros and international partners will contribute an additional 1.8 million Euros, the NEOShield project will research these defence methods. The scientists will focus on data from asteroid observations and lab experiments to generate computer simulations, ultimately determining how best to protect the Earth from future devastating impacts.
Mysterious X-ray flares caught by Chandra may be asteroids falling into the Milky Way's giant black hole. Credit: X-ray: NASA/CXC/MIT/F. Baganoff et al.; Illustrations: NASA/CXC/M.Weiss
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For the past several years, the Chandra telescope has detected X-ray flares occurring about once a day from the supermassive black hole at the center of the Milky Way Galaxy. These flares last a few hours with brightness ranging from a few times to nearly one hundred times that of the black hole’s regular output. What could be causing these unusual, mysterious flares? Scientists have determined that the black hole could be feasting hungrily on asteroids that come too close and vaporizing them, creating the flares. Basically, the black hole is eating asteroids and then belching out X-ray gas.
If confirmed, this result would mean that there is a huge, bustling cloud around the black hole containing hundreds of trillions of asteroids and comets.
“People have had doubts about whether asteroids could form at all in the harsh environment near a supermassive black hole,” said Kastytis Zubovas of the University of Leicester in the United Kingdom, and lead author of a new paper. “It’s exciting because our study suggests that a huge number of them are needed to produce these flares.”
The scientists say this really isn’t as far-fetched as it may sound, as it mirrors an event that regularly takes place in our Solar System: About every three days a comet is destroyed when it flies into the hot atmosphere of the Sun. Despite the significant differences in the two environments, the destruction rate of comets and asteroids by the Sun and the black hole at the center of our galaxy, called Sagittarius A*, or “Sgr A*” for short, may be similar.
These asteroids and comets have likely been ripped from their parent stars, and to create the flare the asteroids or comets have to be fairly large, at least 19 km (12 miles) wide.
The astronomers propose this scenario: An asteroid undergoes a close encounter with another object, such as a star or planet, and is thrown into an orbit headed towards Sgr A*. If the asteroid passes within about 100 million miles of the black hole, roughly the distance between the Earth and the Sun, it would be torn into pieces by the tidal forces from the black hole. These fragments then would be vaporized by friction as they pass through the hot, thin gas flowing onto Sgr A*, similar to a meteor heating up and glowing as it falls through Earth’s atmosphere. A flare is produced and the remains of the asteroid are swallowed eventually by the black hole.
“An asteroid’s orbit can change if it ventures too close to a star or planet near Sgr A*,” said co-author Sergei Nayakshin, also of the University of Leicester. “If it’s thrown toward the black hole, it’s doomed.”
The team says these results reasonably agree with models estimating of how many asteroids are likely to be in this region, assuming that the number around stars near Earth is similar to the number surrounding stars near the center of the Milky Way.
“As a reality check, we worked out that a few trillion asteroids should have been removed by the black hole over the 10-billion-year lifetime of the galaxy,” said co-author Sera Markoff of the University of Amsterdam in the Netherlands. “Only a small fraction of the total would have been consumed, so the supply of asteroids would hardly be depleted.”
This scenario would not be limited to asteroids and comets, however. Planets thrown into orbits too close to Sgr A* also could also be disrupted by tidal forces, although planets in the region are less common. And of course, if a planet was consumed, it would create an even larger flare; and this may have occurred about a century ago when Sgr A* brightened by about a factor of a million. Chandra and other X-ray missions have seen evidence of an X-ray “light echo” reflecting off nearby clouds, providing a measure of the brightness and timing of the flare.
“This would be a sudden end to the planet’s life, a much more dramatic fate than the planets in our solar system ever will experience,” Zubovas said.
Very long observations of Sgr A* will be made with Chandra later in 2012 that will give valuable new information about the frequency and brightness of flares and should help to test the model proposed here to explain them. The team said this work could improve understanding about the formation of asteroids and planets in the harsh environment of Sgr A*.
