The Cassini Telescope is named after Italian-French astronomer Jean- Dominique Cassini (a.k.a. Gian Domenico Cassini), who discovered four of Saturn's major moons -- Iapetus, Rhea, Tethys, and Dione. In 1675, he discovered that Saturn's rings are split largely into two parts by a narrow gap -- known since as the "Cassini Division."
The Cassini orbiter weighs a total of 2,150 kilograms (4,750 pounds); after attaching the 350-kilogram Huygens probe and loading propellants, the spacecraft weight at launch is 5,630 kilograms (12,410 pounds). Because of the very dim sunlight at Saturn's orbit, solar arrays are not feasible and plans call for power to be supplied by a set of radioisotope thermoelectric generators, which use heat from the natural decay of plutonium to generate electricity to run Cassini. These power generators are of the same design as those used on the Galileo and Ulysses missions.
Equipment for a total of twelve science experiments is carried onboard the Cassini orbiter. Another six fly on the Huygens Titan probe, which will detach from the orbiter some four to five months after arrival at Saturn.
The Cassini orbiter advances and extends the United States' technology base with several innovations in engineering and information systems. Whereas previous planetary spacecraft used onboard tape recorders, Cassini pioneers a new solid-state data recorder with no moving parts. The recorder will be used in more than twenty other missions both within and outside NASA.
Similarly, the main onboard computer that directs operations of the orbiter uses a novel design drawing on new families of electronic chips. Among them are very high-speed integrated circuit (VHSIC) chips developed under a U.S. government-industry research and development initiative. Also part of the computer are powerful new application-specific integrated circuit (ASIC) parts; each component replaces a hundred or more traditional chips.
Elsewhere on the Cassini orbiter, the power system benefits from an innovative solid-state power switch being developed from the mission. This switch will eliminate rapid fluctuations called transients that usually occur with conventional power switches, with a significantly improved component lifetime.
As a young boy, American astronomer Edwin Powell Hubble read tales of traveling to undersea cities, journeying to the center of the Earth, and trekking to the remote mountains of South Africa. These stories by adventure novelists Jules Verne and H. Rider Haggard stoked young Hubble¹s imagination of faraway places. He fulfilled those childhood dreams as an astronomer, exploring distant galaxies with a telescope and developing celestial theories that revolutionized astronomy.
But Hubble (1889-1953) didn't settle immediately on the astronomy profession. He studied law as a Rhodes Scholar at Queens College in Oxford, England. A year after passing the bar exam, Hubble realized that his love of exploring the stars was greater than his attraction to law. So he abandoned law for astronomy. I "chucked the law for astronomy and I knew that, even if I were second rate or third rate, it was astronomy that mattered," Hubble said.
He studied astronomy at the University of Chicago and completed his doctoral thesis in 1917. After serving in World War I, he began working at the Mount Wilson Observatory in Pasadena, Calif., studying the faint patches of luminous "fog" or nebulae - the Greek word for cloud - in the night sky.
Using the 100-inch reflecting Hooker Telescope - the largest telescope of its day - Hubble peered farther into space to study the Andromeda nebula. With this powerful telescope, he discovered stars on the outskirts of Andromeda, proving that galaxies - a collection of stars and planets - existed beyond our Milky Way.
Hubble also devised the classification system for galaxies, grouping them by sizes and shapes, that astronomers still use today. He also obtained extensive evidence that the laws of physics outside our galaxy are the same as on Earth, "verifying the principle of the uniformity of nature," he said.
As Hubble continued his study, he made another startling discovery: The universe is expanding. In 1929 he determined that the more distant the galaxy from Earth, the faster it appears to move away. Known as Hubble's Law, this discovery is the foundation of the Big Bang theory. The theory says that the universe began after a huge cosmic explosion and has been expanding ever since. Hubble¹s discovery is considered one of the greatest triumphs of 20th century astronomy.
Albert Einstein could have foretold Hubble's discovery in 1917 when he applied his newly developed General Theory of Relativity to the universe. His theory - that space is curved by gravity - predicted that the universe could not be static but had to expand or contract. Einstein found this prediction so unbelievable that he modified his original theory to avoid the problem. Upon learning of Hubble's discoveries, Einstein said that changing the theory was "the biggest blunder of my life."
The Chandra X-Ray Observatory is a space satellite, the third of NASA's Great Observatories for Space Astrophysics. The first two to be sent to Earth orbit were the Hubble Space Telescope and the Compton Gamma Ray Observatory. Chandra observes the Universe in the high-energy x-ray portion of the electromagnetic spectrum. That band is between the windows on the Universe opened by the Hubble and Compton telescopes.
From a remote outpost on the summit of Hawaii's dormant Mauna Kea volcano, astronomers at the W.M. Keck Observatory probe the deepest regions of the Universe with unprecedented power and precision.
Their instruments are the twin Keck Telescopes, the world's largest optical and and infrared telescopes. Each stands eight stories tall and weighs 300 tons, yet operates with nanometer precision. At the heart of each Keck Telescope is a revolutionary primary mirror. Ten meters in diameter, the mirror is composed of 36 hexagonal segments that work in concert as a single piece of reflective glass.
Keck's capabilities make full use of the summit site. Surrounded by thousands of miles of relatively thermally-stable ocean, the 13,800 foot Mauna Kea summit has no nearby mountain ranges to roil the upper atmosphere or throw light- reflecting dust into the air. Few city lights pollute the viewing. For most of the year, the atmosphere above Mauna Kea is clear, calm and dry.
SOHO was launched on December 2, 1995. The SOHO spacecraft was built in Europe by an industry team led by Matra, and instruments were provided by European and American scientists. There are nine European Principal Investigators (PI's) and three American ones. Large engineering teams and more than 200 co-investigators from many institutions support the PI's in the development of the instruments and in the preparation of their operations and data analysis. NASA is responsible for the launch and mission operations. Large radio dishes around the world which form NASA's Deep Space Network are used to track the spacecraft beyond the Earth's orbit. Mission control is based at Goddard Space Flight Center in Maryland.
The Palomar Observatory is located in northern San Diego county, about 70 miles northeast of the San Diego airport. It has been in operation since 1948.
The Arecibo telescope consists of a 305m fixed reflecting surface, made up of 40,000 individual panels, suspended in a natural limestone sinkhole in northwestern Puerto Rico. Incoming rays are reflected back from the surface to two additional reflectors located 450 feet above on the "platform", a 500 ton structure supported by cables from three towers.
The Gemini Project is an international partnership that will result in two 8.1-meter telescopes (each telescope has a main mirror over 26 feet across.) One telescope is located on Hawaii's Mauna Kea, and the other on Chile's Cerro Pachon. The name Gemini comes from the mythological twins, whose stars will be visible to both telescopes.
Two 6.5 Meter Telescopes at Las Campanas Observatory, Chile.
The Cosmic Background Explorer is a satellite that has been mapping the microwave sky from Earth orbit. It is specifically designed to look for variations in the primordial background radiation.
NEAR Investigates Asteroids
Naturally emitted microwaves are the target of this unusual telescope. Located near the summit of Mauna Kea in Hawaii, the JCMT is helping to open a new window on the universe. Named after the pioneering Scottish physicist who gave us a fundamental understanding of electricity and magnetism,the James Clerk Maxwell Telescope is used to investigate a part of the electromagnetic spectrum that is only now beginning to be explored. The telescope is capable of exploring radio waves with a range of about 0.3 to 2 mm.
The VLT is located at the Paranal Observatory (Atacama, Chile) will be the world's largest and most advanced optical telescope. It comprises four 8.2-m reflecting Unit Telescopes and several moving 1.8-m Auxiliary Telescopes, the light beams of which can be combined in the VLT Interferometer (VLTI). With its unprecedented optical resolution and unsurpassed surface area, the VLT produces extremely sharp images and can record light from the faintest and most remote objects in the Universe. The large telescopes are named ANTU, KUEYEN, MELIPAL and YEPUN.
National Radio Astronomy Observatory
Messier Index M I - M110
The World's Largest Telescopes
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