Banknotes of Denmark 50 krone banknote 1970 Ole Christensen Rømer
Danish National Bank - Danmarks Nationalbank
Obverse: Portrait of the Danish astronomer and physicist Ole Christensen Rømer (1644-1710) by Jacob Coning; On the right-hand side of the banknote is the Round Tower (Rundetårn), a 17th century tower in central Copenhagen with the University's astronomical observatory.
Reverse: Neolithic dolmen, long barrow near Stenvad in Djursland, Jylland (Jutland), drawn by the illustrator and architect Ib Andersen (1907-1969).
Watermark: Crowns and 50 repeated.
Size: 156 x 80 mm.
The 50-krone banknote was issued on 21 May 1957 and has been withdrawn since 21 January 1975.
Banknotes of Denmark, 1950-1970 series
The portrait and landscape series was issued from 1952 to 1964. The 5- and 10-krone banknotes, which had the same format, were the first ones to be issued. A new, taller 10-krone banknote in a different colour was issued in 1954. The banknote series was complete in 1964.
5 Kroner 10 Kroner 50 Kroner 100 Kroner 500 Kroner
Ole Christensen Rømer
Ole Rømer, in full Ole Christensen Rømer, Rømer also spelled Römer or Roemer, Ole also spelled Olaus or Olaf (born Sept. 25, 1644, Århus, Jutland — died Sept. 23, 1710, Copenhagen), Danish astronomer who demonstrated conclusively that light travels at a finite speed.
Rømer went to Paris in 1672, where he spent nine years working at the Royal Observatory. The observatory’s director, Italian-born French astronomer Gian Domenico Cassini, was engaged with a problem that had been studied long before by Galileo: how to use the periodic eclipses of the moons of Jupiter as a universal clock that would be an aid to navigation. (As a satellite goes behind Jupiter, it passes into the shadow of the planet and disappears.) Cassini and his coworkers discovered that the times between successive eclipses of the same satellite (e.g., Io) show an irregularity that is connected with the location of Earth on its own orbit. The time elapsed between successive eclipses of Io becomes shorter as Earth moves closer to Jupiter and becomes longer as Earth and Jupiter draw farther apart. Cassini had considered but then rejected the idea that this might be due to a finite propagation speed for light. In 1676, Rømer announced that the eclipse of Io scheduled for November 9 would be 10 minutes later than the time deduced on the basis of earlier eclipses of the same satellite. When events transpired as he had predicted, Rømer explained that the speed of light was such that it takes light 22 minutes to cross the diameter of Earth’s orbit. (Seventeen minutes would be more accurate.) Dutch mathematician Christiaan Huygens, in his Traité de la lumière (1690; “Treatise on Light”), used Rømer’s ideas to give an actual numerical value for the speed of light that was reasonably close to the value accepted today—though somewhat inaccurate due to an overestimate of the time delay and some error in the then-accepted figure for the diameter of Earth’s orbit.
In 1679 Rømer went on a scientific mission to England, where he met Sir Isaac Newton and the astronomers John Flamsteed and Edmond Halley. Upon his return to Denmark in 1681, he was appointed royal mathematician and professor of astronomy at the University of Copenhagen. At the university observatory he set up an instrument with altitude and azimuth circles and a telescope, which accurately measured the position of celestial objects. He also held several public offices, including that of mayor of Copenhagen in 1705.