Latitude, How American Astronomers Solved the Mystery of Variation by Merri Sue Carter & Carter Bill

Author:Merri Sue Carter & Carter, Bill [Merri Sue Carter]
Language: eng
Format: epub
Publisher: Naval Institute Press, Annapolis, MD, USA
Published: 2002-10-31T16:00:00+00:00

Chapter 9

Newcomb’s Years at the U.S. Naval Observatory

In December of 1830 the U.S. Navy established a depot to maintain the navigational charts and instruments required by fleet operations. Lt. Louis Goldsborough was assigned as officer-in-charge. Among the duties assigned to the depot were to clean, repair and adjust the rates of the marine chronometers used aboard the naval vessels for the determination of longitude at sea. Plans were underway soon after the depot’s start to build an astronomical observatory to collect the observations needed to maintain a master clock and to begin the development of a star catalogue to support celestial navigation.

The new observatory, located on a hill just north of where the Lincoln Memorial now stands in an area known locally as Foggy Bottom, was completed in October 1844. Its complement of astronomical instruments was second to none in the nation, and its first superintendent, Lt. Matthew Fontaine Maury, immediately started work on a star catalogue and on a parallel research effort in oceanography. After some adjustments in mission and name, the U.S. Naval Observatory settled into a long-term program of systematic observations of the sun, moon, planets, and bright stars to determine fundamental celestial positions and motions, and astronomical constants.

In 1845, at the request of the secretary of the navy, the observatory installed a time ball atop the dome that housed a 24 centimeter (9.6 inch) aperture refractor telescope. The time ball was dropped every day precisely at noon, enabling ships in the Potomac River to set their chronometers before setting out to sea. In addition to the direct services provided to the U.S. Navy, the newly established observatory soon began making a number of important contributions to the science of astronomy. When the discovery of the planet Neptune was announced in September 1846 by Johann Gottfried Galle (1812—1910) of the Berlin Observatory, and by Louis d'Arrest (1822—1875), an astronomy student, Lieutenant Maury launched a review of historical astronomical records in search of any possible earlier observations of the planet. With a bit of good fortune, he was able deduce that the French astronomer Joseph de LaLande (1732—1807) had in fact observed Neptune in 1795 but mistook it for a star. By combining the locations of the planet in 1795 and 1846, an excellent set of estimates of the orbital parameters of Neptune were immediately computed.

In 1854 observations made with the Observatory’s 24 centimeter (9.6 inch) telescope revealed the existence of the first minor planet to be discovered by an American astronomer. Two more minor planets were discovered by USNO astronomers during the next six years. These successes aside, the Lazzaroni found Lieutenant Maury lacking in the skills required to lead a world-class astronomical observatory and branded him an anti-intellectual. They were pleased when Maury resigned from the navy in 1861 to join the Confederacy.

The appointment of James Gillis to fill the vacancy left by Maury, occurred at about the same time that the Lazzaron’s attempt to develop the Dudley Observatory into a national observatory ended in failure.

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