Oppolzer, Theodor Egon Ritter von (1841–1886)

Austrian astronomer and mathematician whose interest in asteroids, comets, and eclipses led to his compiling meticulous lists of such bodies and events for the use of other astronomers.

Oppolzer was born in Prague (now in the Czech Republic) and studied medicine, but had a private observatory. In 1866 he became lecturer in astronomy at the University of Vienna, and professor 1875. He was made director of the Austrian Geodetic Survey in 1873.

Oppolzer sought, by observation and calculation, to establish the orbits of asteroids. He was the originator of a novel technique for correcting orbits he found to be inaccurate.

In 1868, Oppolzer participated in an expedition to study a total eclipse of the Sun. Afterwards, he decided to calculate the time and path of every eclipse of the Sun and every eclipse of the Moon for as long a period as possible. The resulting Canon der Finsternisse 1887 covered the period 1207 BC–AD 2163.