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 5Amateur astronomer recording observations of the sun. (from Amateur astronomy)
Image 6An 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 7The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy)
Image 8Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur astronomy)
Image 14Comparison of CMB (Cosmic microwave background) results from satellites COBE, WMAP and Planck documenting a progress in 1989–2013 (from History of astronomy)
Image 20ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy)
Image 21Artist 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)
Image 27Portrait 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 30Segment of the astronomical ceiling of Senenmut's Tomb (circa 1479–1458 BCE), 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)
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Grayscale image of Umbriel from Voyager 2, January 1986. Umbriel's surface is heavily battered; the bright crater Wunda can be seen at the top of the image.
Umbriel (/ˈʌmbriəl/) is the third-largest moon of Uranus. It was discovered on October 24, 1851, by William Lassell. It was discovered at the same time as Ariel and named after a character in Alexander Pope's 1712 poem The Rape of the Lock. Umbriel consists mainly of ice with a substantial fraction of rock, and may be differentiated into a rocky core and an icy mantle. The surface is the darkest among Uranian moons, and appears to have been shaped primarily by impacts. However, the presence of canyons suggests early endogenic processes, and the moon may have undergone an early endogenically driven resurfacing event that obliterated its older surface.
Covered by numerous impact craters reaching 210 km (130 mi) in diameter, Umbriel is the second-most heavily cratered satellite of Uranus after Oberon. The most prominent surface feature is a ring of bright material on the floor of Wunda crater. This moon, like all moons of Uranus, probably formed from an accretion disk that surrounded the planet just after its formation. The Uranian system has been studied up close only once, by the spacecraft Voyager 2 in January 1986. It took several images of Umbriel, which allowed mapping of about 40% of the moon's surface. (Full article...)
... that Jessen's icosahedron has been used for both the "Skwish" children's toy and a NASA proposal for a "super ball bot" to cushion space landers on other planets?
... that Nandivada Rathnasree, who ran Delhi's planetarium, proposed that astronomers could be taught using India's stone-built observatories?
... that Susan Murabana created Africa's first permanent planetarium?
Credit: MONTE D. WRIGHT, Director, NASA History Office
Alouette 1 is a deactivated Canadian satellite that studied the ionosphere. Launched in 1962, it was Canada's first satellite, and the first satellite constructed by a country other than the Soviet Union or the United States.