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This unique spiral galaxy, which is situated 3.2 billion light-years from the Earth, has an extended stream of bright blue knots and diffuse wisps of young stars. [2] It rushes at 3.6 million km/h (1000km/s [2]) through the cluster Abell 2667 and therefore, like a comet, shows a tail, with a length of 600,000 light-years.
The word comet derives from the Old English cometa from the Latin comēta or comētēs. That, in turn, is a romanization of the Greek κομήτης 'wearing long hair', and the Oxford English Dictionary notes that the term (ἀστὴρ) κομήτης already meant 'long-haired star, comet' in Greek.
Common targets of amateur astronomers include the Sun, the Moon, planets, stars, comets, meteor showers, and a variety of deep-sky objects such as star clusters, galaxies, and nebulae. Astronomy clubs are located throughout the world and many have programs to help their members set up and complete observational programs including those to ...
Examples of astronomical objects include planetary systems, star clusters, nebulae, and galaxies, while asteroids, moons, planets, and stars are astronomical bodies. A comet may be identified as both a body and an object: It is a body when referring to the frozen nucleus of ice and dust, and an object when describing the entire comet with its ...
The comet reached minimum elongation on 13 March, on 25°. [4] It reached its peak brightness in April. Jacobson spotted the comet with naked eye on April 18. David H. Levy reported that the comet had an apparent magnitude of 4.7 with the naked eye on April 24. In the end of April the tail of the comet was reported to be up to 2–3 degrees long.
Periodic comets (also known as short-period comets) are comets with orbital periods of less than 200 years or that have been observed during more than a single perihelion passage [1] (e.g. 153P/Ikeya–Zhang). "Periodic comet" is also sometimes used to mean any comet with a periodic orbit, even if greater than 200 years.
C/1961 O1 (Wilson–Hubbard) is a non-periodic comet discovered on 23 July 1961. The comet passed perihelion on 17 July, became visible in twilight on 23 July, having a long tail, and faded rapidly, becoming no longer visible with the naked eye after the first days of August.
De systemate orbis cometici, deque admirandis coeli characteribus (transl.Of the systematics of the world of comets, and on the admirable objects of the sky) is a small tract on comets and other celestial objects by the Sicilian astronomer Giovanni Battista Hodierna published in 1654. [1]