Professional astronomy is split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects. This data is then analyzed using basic principles of physics. Theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. These two fields complement each other. Theoretical astronomy seeks to explain observational results and observations are used to confirm theoretical results.
Astronomy is one of the few sciences in which amateurs play an active role. This is especially true for the discovery and observation of transient events. Amateur astronomers have helped with many important discoveries, such as finding new comets. (Full article...)
Image 6Portrait of the Flemish astronomer Ferdinand Verbiest who became Head of the Mathematical Board and Director of the Observatory of the Chinese emperor in 1669 (from Astronomer)
Image 7Overview of types of observational astronomy by observed wavelengths and their observability. (from Observational astronomy)
Image 9Segment of the astronomical ceiling of Senenmut's Tomb (circa 1479–1458 BC), depicting constellations, protective deities, and twenty-four segmented wheels for the hours of the day and the months of the year (from History of astronomy)
Image 10The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy)
Image 12Comparison of CMB (Cosmic microwave background) results from satellites COBE, WMAP and Planck documenting a progress in 1989–2013 (from History of astronomy)
Image 19Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur astronomy)
Image 23ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy)
Image 29An image of the Cat's Paw Nebula created combining the work of professional and amateur astronomers. The image is the combination of the 2.2-metre MPG/ESO telescope of the La Silla Observatory in Chile and a 0.4-meter amateur telescope. (from Amateur astronomy)
Image 31Artist conception of the Big Bang cosmological model, the most widely accepted out of all in physical cosmology (neither time nor size to scale) (from Physical cosmology)
This is a Featured article, which represents some of the best content on English Wikipedia.
Comet Hale–Bopp, shortly after passing perihelion in April 1997
Comet Hale–Bopp (formally designated C/1995 O1) is a comet that was one of the most widely observed of the 20th century and one of the brightest seen for many decades.
Alan Hale and Thomas Bopp discovered Comet Hale–Bopp separately on July 23, 1995, before it became visible to the naked eye. It is difficult to predict the maximum brightness of new comets with any degree of certainty, but Hale–Bopp exceeded most predictions when it passed perihelion on April 1, 1997, reaching about magnitude −1.8. It was visible to the naked eye for a record 18 months, due to its massive nucleus size. This is twice as long as the Great Comet of 1811, the previous record holder. Accordingly, Hale–Bopp was dubbed the great comet of 1997. (Full article...)
A type Ia supernova (read: "type one-A") is a type of supernova that occurs in binary systems (two stars orbiting one another) in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white dwarf. Image is Supernova remnant N103B taken by the Hubble Space Telescope.
8 September 1966 – The first episode of a new television science fiction series Star Trek is shown on NBC-TV
12 September 2013 – NASA announces that 19 days earlier, Voyager 1 had become the first man-made object to cross the heliopause and enter interstellar space
15 September 2017 – The Cassini spacecraft plunges into the atmosphere of Saturn, ending its 13-year tour of the ringed planet