Johann Palisa

Johann Palisa (December 6, 1848 in Opava ( Opava ), Austrian Silesia, † May 2, 1925 in Vienna ) was an Austrian astronomer. He was known by the discovery of 123 asteroids ( minor planets ), and by the publication of star atlases.

Life

Palisa began his astronomical activity in 1872 as head of the Austrian Naval Observatory Pola, in southern Istria, today Pula, Croatia. Although he stood there beside the astrometric instruments, only a telescope available, the lens with 15 cm had a relatively small diameter, he was soon able to discover some asteroids. Palisa was the first astronomer to have managed for more than 50 minor planets.

A bigger concern, however, it was - in contrast to other researchers - the "Backup " and reliable determination of the orbit of celestial bodies newly found. Many of them went before the discovery of the orbital elements lost through lack of coordination of the observations.

In 1880 he moved to Vienna University Observatory on an assistantship to measure at that time the world's largest telescope can. From here, he reformed the path calculation of asteroids on an international basis. He located the main or asteroid belt (main belt ) - in the circulate, most asteroids - at 2.2 to 3.6 astronomical units and found some to Mars -reaching railways.

Together with Max Wolf in Heidelberg, he introduced new techniques, including the first star atlas to search and identification, but also for purposes of astrophysics. Later, the photographic Wolf Palisa Star cards originated in 210 sheets.

Palisa also ran lunar and solar research, for example in the 1883 expedition for solar eclipse in Tahiti, and took part in the search for the hypothetical planet Vulcan near the Sun. He edited two star catalogs with 4700 exact Örtern - an important basis for railway safety, for which he was awarded the 1906 Prize of the Paris Academy.

Today's meaning

One of these very carefully edited catalogs with more than 1200 fundamental stars wore to the then much-needed astrometric reference system in (see FK3 and Berlin Astronomical Yearbook ), which is dependent on good data earlier today.

Five of his asteroids are research topics today. Although the after ( 433 ) Eros, which was discovered in 1898 by Witt, second "Amor Asteroid " ( 719) Albert ( 1911) was lost after Palisas discovery, but was in 2000 at the Spacewatch telescope ( Arizona) recovered after nine years of searching. He now serves for subsequent analyzes of Jupiter perturbations; with the earth he has an unusual 4:17 resonance of the orbital periods.

Two discoveries Palisas were visited by spacecraft: (253 ) Mathilde of NEAR in 1997, and (243 ) Ida by Galileo in 1993. (216 ) Kleopatra was measured with radar antennas. It was found that the asteroid has an elongated shape, which resembles a dog bone. (140 ) Siwa ( Palisas No. 3, 1874 Pola ) was originally intended to be visited in a few years by ESA 's Rosetta spacecraft on its way to comet Wirtanen. Meanwhile, the Rosetta mission, however, was rescheduled.