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Comet Tralles
The Great Comet of 1819, officially designated as C/1819 N1, also known as Comet Tralles, was an exceptionally bright and easily visible comet, approaching an apparent magnitude of 1–2, discovered July 1, 1819 by the German astronomer Johann Georg Tralles in Berlin. It was the first comet analyzed using polarimetry, by French mathematician François Arago. Discovery On July 1, 1819, Johann Georg Tralles in Berlin observed a brilliant comet low in the sky during the evening twilight. It was confirmed the next night by the astronomer Johann Elert Bode, also in Berlin. Observations On July 2, Tralles found the comet to have a coma of 40″. On July 3, Friedrich Georg Wilhelm von Struve measured the nucleus at 8″ with a tail of several degrees. Heinrich Wilhelm Matthias Olbers reported that the nucleus had an apparent magnitude of 1–2 and a tail about 7–8° long. The comet was last sighted by Struve on October 25. Also on July 3, François Arago used a polarimeter of his o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Georg Tralles
Johann Georg Tralles (15 October 1763 – 19 November 1822) was a German mathematician and physicist. He was born in Hamburg, Germany and was educated at the University of Göttingen beginning in 1783. He became a professor at the University of Bern in 1785. In 1810, he became a professor of mathematics at the University of Berlin. In 1798 he served as the Swiss representative to the French metric convocation, and was a member of its committee on weights and measures. An iron "committee" meter, a duplicate of the prototype archive meter, was then given as a gift to Ferdinand Rudolph Hassler. From 1803 until 1805 these two men worked together on a topological survey of the Canton of Bern. In 1819, he discovered the Great Comet of 1819, Comet Tralles, named after him. He was the inventor of the ''alcoholometer'', a device for measuring the amount of alcohol in a liquid. He died in London, England. The crater Tralles on the Moon The Moon is Earth's only natura ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heinrich Wilhelm Matthias Olbers
Heinrich Wilhelm Matthias Olbers (; ; 11 October 1758 – 2 March 1840) was a German physician and astronomer. Life and career Olbers was born in Arbergen, Germany, today part of Bremen, and studied to be a physician at Göttingen (1777–80). While he was at Göttingen, he studied mathematics with Abraham Gotthelf Kästner. In 1779, while attending to a sick fellow student, he devised a method of calculating cometary orbits which made an epoch in the treatment of the subject. It was the first satisfactory method of calculating cometary orbits. After his graduation in 1780, he began practicing medicine in Bremen. At night he dedicated his time to astronomical observation, making the upper story of his home into an observatory. In 1800, Olbers was one of 24 astronomers invited to participate in the group known as the " celestial police", dedicated to finding new planets in the solar system. On 28 March 1802, Olbers discovered and named the asteroid Pallas. Five years later, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fanny Brawne
Frances "Fanny" Brawne Lindon (9 August 1800 – 4 December 1865) is best known as the fiancée and muse to English Romantic poet John Keats. As Fanny Brawne, she met Keats, who was her neighbour in Hampstead, at the beginning of his brief period of intense creative activity in 1818. Although his first written impressions of Brawne were quite critical, his imagination seems to have turned her into the goddess-figure he needed to worship, as expressed in ''Endymion'', and scholars have acknowledged her as his muse. They became secretly engaged in October 1819, but Keats soon discovered that he was suffering from tuberculosis. His condition limited their opportunities to meet, but their correspondence revealed passionate devotion. In September 1820, he left for the warmer climate of Rome, and her mother agreed to their marrying on his projected return, but he died there in February 1821, aged twenty-five. Brawne drew consolation from her continuing friendship with Kea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Keats
John Keats (31 October 1795 – 23 February 1821) was an English poet of the second generation of Romantic poets, with Lord Byron and Percy Bysshe Shelley. His poems had been in publication for less than four years when he died of tuberculosis at the age of 25. They were indifferently received in his lifetime, but his fame grew rapidly after his death. By the end of the century, he was placed in the canon of English literature, strongly influencing many writers of the Pre-Raphaelite Brotherhood; the '' Encyclopædia Britannica'' of 1888 called one ode "one of the final masterpieces". Jorge Luis Borges named his first encounter with Keats an experience he felt all his life. Keats had a style "heavily loaded with sensualities", notably in the series of odes. Typically of the Romantics, he accentuated extreme emotion through natural imagery. Today his poems and letters remain among the most popular and analysed in English literature – in particular " Ode to a Nightingale", " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Russell Hind
John Russell Hind FRS FRSE LLD (12 May 1823 – 23 December 1895) was an English astronomer. Life and work John Russell Hind was born in 1823 in Nottingham, the son of lace manufacturer John Hind and Elizabeth Russell, and was educated at Nottingham High School. At age 17 he went to London to serve an apprenticeship as a civil engineer, but through the help of Charles Wheatstone he left engineering to accept a position at the Royal Observatory, Greenwich under George Biddell Airy. Hind remained there from 1840 to 1844, at which time he succeeded W. R. Dawes as director of the private George Bishop's Observatory. In 1853 Hind became Superintendent of the Nautical Almanac, a position he held until 1891. Hind is notable for being one of the early discoverers of asteroids. He also discovered and observed the variable stars R Leporis (also known as Hind's Crimson Star), U Geminorum, and T Tauri (also called Hind's Variable Nebula), and discovered the variability of μ Cep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the Equator, the plane of the satellite's orbit is the same as the Earth's equatorial plane, and the satellite's orbital inclination is 0°. The general case for a circular orbit is that it is tilted, spending half an orbit over the northern hemisphere and half over the southern. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°. Orbits The inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the orbital plane and the plane of reference, normally stated in degrees. For a satellite orbiting a planet, the plane of reference is usually the plane containing the planet's equator. For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecliptic
The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic against the background of stars. The ecliptic is an important reference plane and is the basis of the ecliptic coordinate system. Sun's apparent motion The ecliptic is the apparent path of the Sun throughout the course of a year. Because Earth takes one year to orbit the Sun, the apparent position of the Sun takes one year to make a complete circuit of the ecliptic. With slightly more than 365 days in one year, the Sun moves a little less than 1° eastward every day. This small difference in the Sun's position against the stars causes any particular spot on Earth's surface to catch up with (and stand directly north or south of) the Sun about four minutes later each day than it would if Earth did not orbit; a day on Earth is therefore 24 ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parabolic Trajectory
In astrodynamics or celestial mechanics a parabolic trajectory is a Kepler orbit with the eccentricity equal to 1 and is an unbound orbit that is exactly on the border between elliptical and hyperbolic. When moving away from the source it is called an escape orbit, otherwise a capture orbit. It is also sometimes referred to as a C3 = 0 orbit (see Characteristic energy). Under standard assumptions a body traveling along an escape orbit will coast along a parabolic trajectory to infinity, with velocity relative to the central body tending to zero, and therefore will never return. Parabolic trajectories are minimum-energy escape trajectories, separating positive-energy hyperbolic trajectories from negative-energy elliptic orbits. Velocity The orbital velocity (v) of a body travelling along parabolic trajectory can be computed as: :v = \sqrt where: *r is the radial distance of orbiting body from central body, *\mu is the standard gravitational parameter. At any po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Elements
Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same orbit, but certain schemes, each consisting of a set of six parameters, are commonly used in astronomy and orbital mechanics. A real orbit and its elements change over time due to gravitational perturbations by other objects and the effects of general relativity. A Kepler orbit is an idealized, mathematical approximation of the orbit at a particular time. Keplerian elements The traditional orbital elements are the six Keplerian elements, after Johannes Kepler and his laws of planetary motion. When viewed from an inertial frame, two orbiting bodies trace out distinct trajectories. Each of these trajectories has its focus at the common center of mass. When viewed from a non-inertial frame centered on one of the bodies, only the traje ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transit (astronomy)
In astronomy, a transit (or astronomical transit) is a phenomenon when a celestial body passes directly between a larger body and the observer. As viewed from a particular vantage point, the transiting body appears to move across the face of the larger body, covering a small portion of it. The word "transit" refers to cases where the nearer object appears smaller than the more distant object. Cases where the nearer object appears larger and completely hides the more distant object are known as ''occultations''. However, the probability of seeing a transiting planet is low because it is dependent on the alignment of the three objects in a nearly perfectly straight line. Many parameters of a planet and its parent star can be determined based on the transit. In the Solar System One example of a transit involves the motion of a planet between a terrestrial observer and the Sun. This can happen only with inferior planets, namely Mercury and Venus (see transit of Mercury ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Elements
Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same orbit, but certain schemes, each consisting of a set of six parameters, are commonly used in astronomy and orbital mechanics. A real orbit and its elements change over time due to gravitational perturbations by other objects and the effects of general relativity. A Kepler orbit is an idealized, mathematical approximation of the orbit at a particular time. Keplerian elements The traditional orbital elements are the six Keplerian elements, after Johannes Kepler and his laws of planetary motion. When viewed from an inertial frame, two orbiting bodies trace out distinct trajectories. Each of these trajectories has its focus at the common center of mass. When viewed from a non-inertial frame centered on one of the bodies, only the traje ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polarimetric
Polarimetry is the measurement and interpretation of the polarization of transverse waves, most notably electromagnetic waves, such as radio or light waves. Typically polarimetry is done on electromagnetic waves that have traveled through or have been reflected, refracted or diffracted by some material in order to characterize that object. Plane polarized light: According to the wave theory of light, an ordinary ray of light is considered to be vibrating in all planes of right angles to the direction of its propagation. If this ordinary ray of light is passed through a nicol prism, the emergent ray has its vibration only in one plane. Applications Polarimetry of thin films and surfaces is commonly known as ellipsometry. Polarimetry is used in remote sensing applications, such as planetary science, astronomy, and weather radar. Polarimetry can also be included in computational analysis of waves. For example, radars often consider wave polarization in post-processing to impr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
