Uranus Discovery 234 Years Ago on March 13, 1781, by Sir William Herschel

Summary: Friday, March 13, 2015, marks the 234th anniversary of the discovery of Uranus by Sir William Herschel.

false color image of Uranus generated by Erich Karkoschka from data taken Aug. 8, 1998, with Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer: NASA/JPL/STScI (Space Telescope Science Institute), Public Domain, via NASA Jet Propulsion Laboratory

March 13, 2015, which falls on a Friday, commemorates the 234th anniversary of the discovery of Uranus by Sir William Herschel on March 13, 1781, which fell on a Tuesday.

Born into a musical family in Hanover, in today's north central Germany, Friedrich Wilhelm Herschel (Nov. 15, 1738-Aug. 25, 1822) first applied his diligence and genius to music, playing at least four instruments (harpsichord, oboe, organ, violin) and composing in a variety of musical genres, including 24 symphonies. With the French occupation of Hanover in the wake of their victory on July 26, 1757, at the Battle of Hastenbeck, William, then aged 19, migrated with his older brother Heinrich Anton Jacob Herschel (November 1734-1792) to England, where he anglicized his first and second names to Frederick William.

Through his musical interests, William developed a passion for mathematics and lenses that led him to astronomy. William began building his own versions of reflecting telescopes, a mid-17th century invention.

Scientific genius Sir Isaac Newton (Dec. 25, 1642-March 20, 1726/7) generally is credited with completing the first functional reflecting telescope in 1668. Also known as a reflector, a reflecting telescope is a type of optical telescope based upon catoptrics (Greek: κάτοπτρον, katoptron, "mirror"), the branch of optics (study of light) using mirrors to gather and focus light.

By May 1773, William was an impassioned sky gazer, searching with his homemade, customized telescopes for double stars, which are star pairs seemingly in proximity in the sky, and also for planets (Ancient Greek: ἀστήρ πλανήτης, astēr planētēs, "wandering star").

With his appointment in 1766 as organist of Octagon Chapel in the resort city of Bath in England's South West county of Somerset, William had settled into a small, Georgian-style townhouse with three stories plus an attic and a basement at 19 New King Street. In the property's garden, off the basement's rear kitchen, William built a workshop for his design experiments on telescopes. William logged many hours -- with the assistance of his sister Caroline (March 16, 1750-Jan. 9, 1848) -- polishing his telescopes' mirrors, made of speculum metal, a mixture of two-thirds copper and one-third tin.

On Friday, March 13, 1981, the 200th year anniversary of William's planetary discovery, his townhouse opened as the Herschel Museum of Astronomy, under the ownership of the Herschel House Trust.

It was through a 7-foot telescope with a 6.2-inch aperture that he had made in his workshop that William espied Uranus on Tuesday, March 13, 1781. He first assumed that the celestial body was either a comet or a star. His sister Caroline took notes as he discovered his sighting.

By 1783, William accepted his discovery as a planet, which he named Georgium Sidus ("George's Star") in honor of George III (June 4, 1738-Jan. 29, 1820), whose kingly reign over Great Britain and Ireland began Oct. 25, 1760.

In 1784, French astronomer Joseph Jérôme Lefrançois de Lalande (July 11, 1732-April 4, 1807) proposed renaming the seventh planet from Earth's sun as Herschel.

Included among mythology-based names as alternatives to the Georgian Planet was Uranus, proposed in 1785 by German astronomer Johann Elert Bode (Jan. 19, 1747-Nov. 23, 1826) to conform with the patronymic chain of Jupiter as father of Mars, Saturn as father of Jupiter and Uranus as father of Saturn. The name of Uranus achieved universal acceptance in 1850 with its inclusion in The Nautical Almanac, published as a guide for celestial navigation since 1767.

In the intervening two and one-third centuries that have passed since Uranus caught William's attention, the blue-green planet continues to stand out. Uranus is honored as the first planet to be discovered by the fairly newly invented reflecting telescope, trailblazing harbinger of continual discoveries, including Neptune in 1846, on the time-space continuum. The blue-green ice giant also is the only solar system planet with the Greek form (Ancient Greek: Οὐρανός,Ouranos, "heaven, sky"), not the Roman form (Latin: Caelus), of a deity from classical mythology.

replica of telescope through which William Herschel discovered the planet Uranus, Herschel Museum of Astronomy, Bath, England: Mike Young, Public Domain, via Wikimedia Commons 

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

false color image of Uranus generated by Erich Karkoschka from data taken Aug. 8, 1998, with Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer: NASA/JPL/STScI (Space Telescope Science Institute), Public Domain, via NASA Jet Propulsion Laboratory @ http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA02963

replica of telescope through which William Herschel discovered the planet Uranus, Herschel Museum of Astronomy, Bath, England: Mike Young, Public Domain, via Wikimedia Commons @ http://commons.wikimedia.org/wiki/File:HerschelTelescope.jpg

For further information:

Herschel, Mr., and Dr. Watson, Jun. of Bath. "Account of a Comet. Read April 26, 1781." Philosophical Transactions of the Royal Society of London, vol. LXXI [71] (1 January 1781): 492 - 501.
Available via Wikimedia Commons @ http://commons.wikimedia.org/wiki/File:Herschel-Account_of_a_Comet.pdf

“IoE Number 443114; Nos. 18 – 19 New King Street.” Images of England.
Available @ http://www.imagesofengland.org.uk/details/default.aspx?id=443114

Marriner, Derdriu. "Uranus the Blue Green Ice Giant: Sideways Seventh Planet From the Sun." Earth and Space News. Friday, March 13, 2015.
Available @ https://earth-and-space-news.blogspot.com/2015/03/uranus-blue-green-ice-giant-sideways.html

Mullaney, James. The Herschel Objects and How to Observe Them. New York: Springer Science+Business Media, 2007.

Talcott, Richard. “The Sky This Week: March 6 – 15, 2015.” Astronomy Magazine > Observing > The Sky This Week. March 6, 2015.
Available @ http://astronomy.com/observing/sky-this-week/2015/03/march-615-2015

“Uranus: Overview.” NASA Solar System Exploration > Planets > Uranus.
Available @ http://solarsystem.nasa.gov/planets/profile.cfm?object=Uranus