Using Cherenkov Telescopes for Outer Solar System Science

On the Use of Cherenkov Telescopes for Outer Solar System Body Occultations

Authors:

Lackey et al

Abstract:

Imaging Atmosphere Cherenkov Telescopes (IACT) are arrays of very large optical telescopes that are well-suited for rapid photometry of bright sources. I investigate their potential in observing stellar occultations by small objects in the outer Solar System, Transjovian Objects (TJOs). These occultations cast diffraction patterns on the Earth. Current IACT arrays are capable of detecting objects smaller than 100 meters in radius in the Kuiper Belt and 1 km radius out to 5000 AU. The future Cherenkov Telescope Array (CTA) will have even greater capabilities. Because the arrays include several telescopes, they can potentially measure the speeds of TJOs without degeneracies, and the sizes of the TJOs and background stars. I estimate the achievable precision using a Fisher matrix analysis. With CTA, the precisions of these parameter estimations will be as good as a few percent. I consider how often IACTs can observe occultations by members of different TJO populations, including Centaurs, Kuiper Belt Objects (KBOs), Oort cloud objects, and satellites and Trojans of Uranus and Neptune. The great sensitivity of IACT arrays means that they likely detect KBO occultations once every O(10) hours when looking near the ecliptic. IACTs can also set useful limits on many other TJO populations.

Automatic Detection of Asteroids

Automatic Detection of Asteroids and Meteoroids - A Wide Field Survey

Authors:

Vereš et al

Abstract:

We propose a low-cost robotic optical survey aimed at 1−300 m Near Earth Objects (NEO) based on four state-of-the-art telescopes having extremely wide field of view. The small Near-Earth Asteroids (NEA) represent a potential risk but also easily accessible space resources for future robotic or human space in-situ exploration, or commercial activities. The survey system will be optimized for the detection of fast moving - trailed - asteroids, space debris and will provide real-time alert notifications. The expected cost of the system including 1-year development and 2-year operation is 1,000,000 EUR. The successful demonstration of the system will promote cost-efficient ADAM-WFS (Automatic Detection of Asteroids and Meteoroids - A Wide Field Survey) systems to be built around the world.

Synthetic Tracking: a new Technique for Finding Near Earth Asteroids as Small as 7 Meters in Diameter

FINDING VERY SMALL NEAR-EARTH ASTEROIDS USING SYNTHETIC TRACKING

Authors:

Shao et al

Abstract:

We present an approach that significantly increases the sensitivity for finding and tracking small and fast near-Earth asteroids (NEAs). This approach relies on a combined use of a new generation of high-speed cameras which allow short, high frame-rate exposures of moving objects, effectively "freezing" their motion, and a computationally enhanced implementation of the "shift-and-add" data processing technique that helps to improve the signal-to-noise ratio (SNR) for detection of NEAs. The SNR of a single short exposure of a dim NEA is insufficient to detect it in one frame, but by computationally searching for an appropriate velocity vector, shifting successive frames relative to each other and then co-adding the shifted frames in post-processing, we synthetically create a long-exposure image as if the telescope were tracking the object. This approach, which we call "synthetic tracking," enhances the familiar shift-and-add technique with the ability to do a wide blind search, detect, and track dim and fast-moving NEAs in near real time. We discuss also how synthetic tracking improves the astrometry of fast-moving NEAs. We apply this technique to observations of two known asteroids conducted on the Palomar 200 inch telescope and demonstrate improved SNR and 10 fold improvement of astrometric precision over the traditional long-exposure approach. In the past 5 yr, about 150 NEAs with absolute magnitudes H = 28 (~10 m in size) or fainter have been discovered. With an upgraded version of our camera and a field of view of (28 arcmin)2 on the Palomar 200 inch telescope, synthetic tracking could allow detecting up to 180 such objects per night, including very small NEAs with sizes down to 7 m.

Gemini Planet Imager has First Light

After nearly a decade of development, construction, and testing, the world's most advanced instrument for directly imaging and analyzing planets around other stars is pointing skyward and collecting light from distant worlds.

The instrument, called the Gemini Planet Imager (GPI), was designed, built, and optimized for imaging faint planets next to bright stars and probing their atmospheres. It will also be a powerful tool for studying dusty, planet-forming disks around young stars. It is the most advanced such instrument to be deployed on one of the world's biggest telescopes – the 8-meter Gemini South telescope in Chile.

"Even these early first-light images are almost a factor of 10 better than the previous generation of instruments. In one minute, we are seeing planets that used to take us an hour to detect," says Bruce Macintosh of the Lawrence Livermore National Laboratory who led the team that built the instrument.

GPI detects infrared (heat) radiation from young Jupiter-like planets in wide orbits around other stars, those equivalent to the giant planets in our own Solar System not long after their formation. Every planet GPI sees can be studied in detail.

"Most planets that we know about to date are only known because of indirect methods that tell us a planet is there, a bit about its orbit and mass, but not much else," says Macintosh. "With GPI we directly image planets around stars – it's a bit like being able to dissect the system and really dive into the planet's atmospheric makeup and characteristics."

GPI carried out its first observations last November – during an extremely trouble-free debut for an extraordinarily complex astronomical instrument the size of a small car. "This was one of the smoothest first-light runs Gemini has ever seen" says Stephen Goodsell, who manages the project for the observatory.

For GPI's first observations, the team targeted previously known planetary systems, including the well-known Beta Pictoris system; in it GPI obtained the first-ever spectrum of the very young planet Beta Pictoris b. The first-light team also used the instrument's polarization mode – which can detect starlight scattered by tiny particles – to study a faint ring of dust orbiting the very young star HR4796A. With previous instruments, only the edges of this dust ring, (which may be the debris remaining from planet formation), could be seen, but with GPI astronomers can follow the entire circumference of the ring.

Although GPI was designed to look at distant planets, it can also observe objects in our Solar System. The accompanying test images of Jupiter's moon Europa, for example, can allow scientists to map changes in the satellite's surface composition. The images were released today at the 223rd meeting of the American Astronomical Society in Washington DC.

"Seeing a planet close to a star after just one minute, was a thrill, and we saw this on only the first week after the instrument was put on the telescope!" says Fredrik Rantakyro a Gemini staff scientist working on the instrument. "Imagine what it will be able to do once we tweak and completely tune its performance."

link.  bad astronomy link.

Martian Spysat Proposed

Imagine you had a Hubble-class telescope and could use in any way you wanted to explore planets. What would you do with it?

A number of scientists have had the chance to explore that question courtesy of an American spy agency. A year ago, NASA received a surprise phone call from the National Reconnaissance Agency (NRO), which flies spy satellites, asking if it would like two spare, Hubble-class space telescopes. NASA’s managers said,”Yes!,” and now the agency is looking for the best uses for the telescopes. The highest priority is to see if one telescope could be used to meet the needs for the Wide-Field Infrared Survey Telescope (WFIRST) to study dark energy. That potentially leaves a second telescope for other deep space or solar system studies.

Before I describe the concepts discussed at a recent conference, a truth in advertising statement is required. Each telescope represents $250M worth of hardware. However, not all the systems needed for an actual satellite are included, instruments are not included, and the whole lot would need to be launched. Figures I’ve read suggest that turning each telescope into a working observatory would cost approximately $1B, depending on the specifics of the mission. NASA’s current budgets have no room to fund a single mission, much less two. In a few years, there may be room for a mission or two, so the space agency is soliciting ideas.

Too bad you could not lob this sucker to the Jovian system.  That'd be beyond awesome for exploring the Galilean Moons. There are two telescopes so you need not worry about choosing only one mission.  There are parts for another...if that one could be completed too...

dude.

How the NRO Saved NASA's Astrophysics Program Continued

When astronomer Alan Dressler was invited to see what might be the future of NASA’s astrophysics programme, he had to leave his mobile phone behind, lest he be tempted to grab a quick snapshot. As he and a dozen others passed through the ITT Exelis facility in Rochester, New York, a guide held up a flashing red light, to warn working Exelis engineers to seal their lips in front of people without security clearance.

Their destination was the cavernous clean area of Building 1230, where two 2.4-metre telescopes, each as big as the Hubble Space Telescope and never flown, rested on low pedestals. “It seemed almost too good be true,” says Dressler, an astronomer at the Carnegie Observatories in Pasadena, California. “Things like this just don’t drop on your doorstep.”

The unexpected gift comes from the US National Reconnaissance Office (NRO), a secretive surveillance agency that built the telescopes to peer down on Earth. In June, NASA revealed that the NRO had bequeathed the scopes to the space agency because they were no longer needed. Now NASA has to figure out what it will do with them — and whether it can afford the cost of kitting them out with instruments and sending them into orbit.

This month, NASA plans to announce a science-definition team that will embark on that assessment. The team will report by April 2013 to NASA administrator Charles Bolden on the pros, cons and costs of adapting one of the telescopes for a mission to investigate dark energy, the phenomenon thought to be accelerating the expansion of the Universe. But astronomers are already encouraged. As the veil of secrecy surrounding the telescopes lifts, astronomers are beginning to size up the devices’ capabilities. And so far, they are liking what they see — so much so that they are now talking about tacking on an instrument that would detect extrasolar planets directly. “I think the enthusiasm has only increased as time has gone on,” says Dressler.

I talked about this before here here. I am still curious which spysat model this is.  I find it amusing and interesting that part of the deal is that NASA cannot point it back at Earth.