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transit compass

(Encyclopedia)transit compass: see surveying.

compass

(Encyclopedia)compass. 1 In mathematics, an instrument for making circles and measuring distances. Frequently called a pair of compasses, it consists of two metal legs with one end of each attached to a pivot to fo...

transit

(Encyclopedia)transit, in astronomy, passage of a body across a meridian or passage of a small body across the visible disk of a larger one. (The passage of a large body across a smaller one is called an eclipse or...

compass plant

(Encyclopedia)compass plant or rosinweed, large, coarse North American perennial herb (Silphium laciniatum) of the family Asteraceae (aster family), found chiefly in open grasslands. The deeply cut leaves tend to p...

radio compass

(Encyclopedia)radio compass: see radio range.

mass transit

(Encyclopedia)mass transit, public transportation systems designed to move large numbers of passengers. The history of mass transportation is intimately connected to industrialization, urbanization, and the sepa...

rapid transit

(Encyclopedia)rapid transit, transportation system designed to allow passenger travel within or throughout an urban area, usually employing surface, elevated, or underground railway systems or some combination of t...

transit instrument

(Encyclopedia)transit instrument or transit, telescope devised to observe stars as they cross the meridian and used for determining time. Its viewing tube swings on a rigid horizontal axis restricting its movements...

vernier

(Encyclopedia)vernier vûrˈnēr [key], auxiliary scale, either straight or an arc of a circle, designed to slide along a fixed scale. Its unit divisions, usually smaller than those on the fixed scale, permit a far...

Halley, Edmond

(Encyclopedia)Halley, Edmond hălˈē, hôˈlē [key], 1656–1742, English astronomer and mathematician. He is particularly noted as the first astronomer to predict the return of a comet and the first to point out...