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Johann_Heinrich_Mädler.jpg
Johann Heinrich von Mädler (May 29 1794 – March 14 1874) was a German astronomer.
He was orphaned at age 19 by an outbreak of typhus, and found himself responsible for raising three younger sisters. He began giving academic lessons as a private tutor and in this way met Wilhelm Beer, a wealthy banker in 1824.
In 1829 Beer decided to set up a private observatory with a 95-mm refractor telescope made by Joseph von Fraunhofer, and Mädler worked there. In 1830 they began producing drawings of Mars which later became the first true maps of that planet. They were the first to choose what is today known as Sinus Meridiani as the prime meridian for Mars maps.
They made a preliminary determination for Mars' rotation period, which was off by almost 13 seconds. A later determination in 1837 was off by only 1.1 seconds.
They also produced the first exact map of the Moon, Mappa Selenographica, published in four volumes in 1834–1836. In 1837 a description of the Moon (Der Mond) was published. Both were the best descriptions of the Moon for many decades, not superseded until the map of Johann Friedrich Julius Schmidt in the 1870s. Beer and Mädler drew the firm conclusion that the features on the Moon do not change, and there is no atmosphere or water.
In 1836, Johann Franz Encke appointed Mädler an observer at the Berlin Observatory, and he observed with its 240-mm refractor. In 1840, Mädler was appointed director of the Dorpat Observatory in Tartu, Estonia, succeeding Friedrich Wilhelm Struve who had moved to Pulkovo Observatory. He carried out meteorological as well as astronomical observations. He continued Struve's observations of double stars. He remained in Tartu until he retired in 1865, and then returned to Germany.
By examining the proper motions of stars, he came up with his "Central Sun Hypothesis", according to which the center of the galaxy was located in the Pleiades star cluster and that the Sun revolves around it. He got the location wrong.
He published many scientific works, among the two-volume History of Descriptive Astronomy in 1873.
Notwithstanding several singular scientific errors is J. H. von Mädler, without doubt, one of the great and eminent astronomers of the 19th century. To his honours Mädler crater on the Moon and Mädler crater on Mars are named after him.
The conventional tropic year according to von Mädler
Next to his others, numerous and important works, von Mädler made prominent, however nearly unknown, calculations concerning the true length of the tropical year with precisions never attaint before. Based on his results, he proposed to Russia, which at this time always applied the conventional tropic year according to Sosigenes of Alexandria of exactly 365 days 6 hours (cf. Julian Calendar), to reach the backwardness of 12 days relative to the Gregorian Calendar in the year 1900, but then, – astronomically perfectly accurate – to respect a new, first proposed by von Mädler himself, 128 years ruler for the exceptionally common years. (The only odd thing in Mädler's proposal was, that neither the year 1900, nor then 2028, 2156 etc. [=1900 +128 +128...] itself are divisible by 128.)
As is generally known, neither Tsar, nor orthodox clergy received this unsolicited proposal. After the Bolshevik Revolution in Russia, Lenin hurried up to apply the western (papal) calendar, with its conventional tropic year of 365,2425 days (i.e. 365d. 5h 49min. 12s) due to Christophorus Clavius (1537-1612). But this one was astronomically true about 6000 years ago. The modern science calculates, often still now, with conventional tropic year according to Simon Newcomb (1835-1909) of 365,2422 days (= 365d. 5h 48min. 46,08s). But this one is not more than an approximate decimal rounding value. The real tropical year 2000.0 (measured by Pierre Bretagnon) was 365,242190517 days, that is about 365d. 5h 48min. 45,26s. That is also very closely to the conventional tropic year according to von Mädler: 365,2421875 days, exactly 365d. 5h 48min. and 45s or 365d. 6h. minus 11min. 15s (cf. Hexadecimal Time) But because the real tropical year shortens about half a second by century, this one will exactly attain the von Mädler proposed value in only a few of decades. Thence we can well expect that yet we can count on the conventional tropic year according to von Mädler.
External links
Obituary
- MNRAS 35 (1875) 171 (http://adsabs.harvard.edu//full/seri/MNRAS/0035//0000171.000.html)de:Johann Heinrich von Mädler