Transitofa Star

Transit of a Star occurs when the star just crosses the meridian, and is the phenomenon observed for determining the right ascension of the star. [TRANSIT INSTRUMENT.] The absolute right ascension of a star is obtained by noting the time which elapses between its transit and that of the sun, the declination of the latter being observed at the same time. Transit is also the name given to the passage of one celestial body across another. Thus Jupiter's satellites exhibit transits across his disc in front as well as suffer eclipses behind him. The more important transits, however, are those of the inferior planets Venus and Mercury across the sun's disc. The transit of Venus especially has caused more excitement than any other astronomical phenomenon, and more pains have been taken to observe it accurately. Correct observations on this motion owe their importance to the fact that they have been used as the chief factors in the determination of the sun's distance from us, and therefore in the estimation of all astronomical measurements. [VENUS.]