Christoph Arnold
Encyclopedia
Christoph Arnold was a German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 amateur astronomer
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

.

Born in Sommerfeld near Leipzig
Leipzig
Leipzig Leipzig has always been a trade city, situated during the time of the Holy Roman Empire at the intersection of the Via Regia and Via Imperii, two important trade routes. At one time, Leipzig was one of the major European centres of learning and culture in fields such as music and publishing...

, Arnold was a farmer by profession. Interested in astronomy, he spotted the great comet
Great comet
A Great Comet is a comet that becomes exceptionally bright. There is no official definition; often the term will be attached to comets that become bright enough to be noticed by casual observers who are not actively looking for them, and become well known outside the astronomical community. Great...

 of 1683, eight days before Hevelius did. He also observed the great comet of 1686. In 1686, Kirch went to Leipzig
Leipzig
Leipzig Leipzig has always been a trade city, situated during the time of the Holy Roman Empire at the intersection of the Via Regia and Via Imperii, two important trade routes. At one time, Leipzig was one of the major European centres of learning and culture in fields such as music and publishing...

. There, he observed the great comet
Great comet
A Great Comet is a comet that becomes exceptionally bright. There is no official definition; often the term will be attached to comets that become bright enough to be noticed by casual observers who are not actively looking for them, and become well known outside the astronomical community. Great...

 of 1686, together with Gottfried Kirch
Gottfried Kirch
Gottfried Kirch was a German astronomer. The son of a shoemaker in Guben, Electorate of Saxony, Kirch first worked as a calendar-maker in Saxonia and Franconia. He began to learn astronomy in Jena, and studied under Hevelius in Danzig...

. There, Kirch met his second wife, Maria Margarethe Winckelmann
Maria Margarethe Kirch
Maria Margarethe Kirch was a German astronomer, and one of the first famous astronomers of her period.-Early life:...

 (1670–1720), who had actually learned astronomy from Arnold.

Arnold observed the transit of Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...

 in front of the sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

 on October 13, 1690. For this work, he received some money and a tax exemption
Tax exemption
Various tax systems grant a tax exemption to certain organizations, persons, income, property or other items taxable under the system. Tax exemption may also refer to a personal allowance or specific monetary exemption which may be claimed by an individual to reduce taxable income under some...

 from the town of Leipzig. He was the author of Göttliche Gnadenzeichen, in einem Sonnenwunder vor Augen gestellt (Leipzig, 1692) which contains an account of the transit of Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...

 in 1690.

He died at Leipzig.

The crater Arnold
Arnold (crater)
Arnold is a lunar crater that is located in the north-northeastern part of the visible Moon, near the lunar limb. This location gives the crater a notably oval appearance due to foreshortening, although the formation is actually relatively round. It lies to the northeast of the Mare Frigoris, to...

 on the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

is named after him.

Sources

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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