July 22 – Friedrich Wilhelm Bessel

Today is the anniversary of the birth, in 1784 of Friedrich Wilhelm Bessel, the German astronomer who was the first to use parallax to find the distance to a star.  The star in question was 61 Cygni, which Bessel decided was 10.3 light years away (the current measurement is 11.4 ly).  One can only marvel at Bessel’s ability, in 1838, to measure the unbelievably small angles involved.  The feat was somewhere akin to measuring the differences in direction of the left and right edges of a Brussells sprout located about three miles away.

Portrait of Bessel by the Danish artist C A Jensen

Portrait of Bessel by the Danish artist C A Jensen


Asteroid 30 Urania was discovered on July 22nd 1854 by John Russell Hind.  It is a main belt S-type asteroid of about 100km diameter at its widest point.

Urania

Urania

Urania is the Greek muse of astronomy, a daughter of Zeus, and great-granddaughter of Uranus.  She is usually represented wearing a cloak embroidered with stars.  The allegorical representation above is by the French portrait painter Jean Louis Tocqué.


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