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Bürgi, Joost

(Encyclopedia)Bürgi, Joost or Jost, 1552–1632, Swiss mathematician and instrument maker. As the official clockmaker (1579–92) to Duke Wilhelm IV of Hesse-Kassell, he developed the first clock with a minute han...

celestial sphere

(Encyclopedia)celestial sphere, imaginary sphere of infinite radius with the earth at its center. It is used for describing the positions and motions of stars and other objects. For these purposes, any astronomical...

Tianjin

(Encyclopedia)Tianjin or Tientsin both: tyänˈjĭnˈ [key], city and independent municipality (2010 pop. 12,938,224), NE China. In E central Hebei prov., it is a politically independent unit (4,400 sq mi/11,399 sq...

module

(Encyclopedia)module. 1 Term derived from the Latin modulus, a unit of measure in classical architecture equal to half the diameter of a column at its base. This unit was used in proportioning the classical orders ...

galactic coordinate system

(Encyclopedia)galactic coordinate system, astronomical coordinate system in which the principal axis is the galactic equator (the intersection of the plane of the Milky Way with the celestial sphere) and the refere...

McDonald Observatory

(Encyclopedia)McDonald Observatory, astronomical observatory located on Mt. Locke, near Fort Davis, Tex.; founded in 1932, sponsored by the Univ. of Texas in cooperation with the Univ. of Chicago. Its equipment inc...

Banneker, Benjamin

(Encyclopedia)Banneker, Benjamin, 1731–1806, African-American inventor, astronomer, and mathematician, b. Baltimore co., Md., at what is now Ellicott's Mills. A free black, Banneker was essentially self-taught. H...

Pulkovo

(Encyclopedia)Pulkovo po͞olˈkəvə [key], astronomical observatory, S of St. Petersburg, NW Russia. Pulkovo was built (1834–39) under a commission headed by F. G. W. von Struve. In 1839 its 15-in. (38-cm) refra...

Pickering, William Henry

(Encyclopedia)Pickering, William Henry, 1858–1938, American astronomer, b. Boston, grad. Massachusetts Institute of Technology (B.S., 1879). He taught at the Massachusetts Institute of Technology (1880–87) and ...

virtual observatory

(Encyclopedia)virtual observatory, a collection of integrated astronomical data archives and software tools that utilize computer networks to create an environment in which research can be conducted. Several countr...