“Bite-Size Bits of Local, National, and Global History”
“Bite-Size Bits of Local, National, and Global History”
Gaithersburg in Montgomery County, Maryland — The American Northeast (Mid-Atlantic)

The Observatory

Latitude Observatory Park

The Observatory Marker image. Click for full size.
By Allen C. Browne, June 23, 2012
1. The Observatory Marker
Inscription. U.S. Coast and Geodetic Survey Assistant, Edwin Smith or Rockville, Maryland, was assigned to oversee construction and operations at the Gaithersburg Observatory. Original plans for the Ukiah and Gaithersburg Observatories, prepared by the Central Bureau in Germany, specified that the buildings be constructed of iron. When Mr. smith learned that replicas of the Japanese and Italian Stations could not be built with the projected budget, he revised the plans,substituting wood for the specified iron.

The construction of the Gaithersburg Latitude Observatory was completed in August 1899 and it recieved its Zenith Telescope (ZT) in September of that same year. The facility offically opened on October 18, 1899.

The Gaithersburg Observatory was constructed with a double wall of Georgia and Virginia pine to minimize the difference between the interior and exterior temperatures; a difference that might affect the heat-sensitive Zenith Telescope. The roof was designed in two parts that move east and west on iron wheels operated manually by a rope pulley system within the building. The six-foot, six-inch full opening was always used at Gaithersburg to accommodate the large Zenith Telescope. This type of telescope points at the zenith, or the direction pointing straight above a particular location. Zenith Telescopes are fitted
The Observatory Marker image. Click for full size.
By Allen C. Browne, July 15, 2012
2. The Observatory Marker
with extremely sensitive spirit bubble levels to facilitate the accurate angle measurements required in the determination of astronomic latitude. The motion-sensitive ZT is mounted on a pier sunk into the ground to negate any vibrations transmitted from surrounding sources like traffic or trains.

The small size of the building and the esoteric character of the work that took place within speak modestly of the international importance of this landmark. The research conducted here provided all the data used in polar motion studies for decades, and fostered international cooperation that transcended the differences between nations during times of war and international strain.

From its construction in 1899 until the obsolence of human observers forced its closing in 1982, the Gaithersburg Latitude Observatory played an integral role in the study of Earth's scientific behavior. Following its closure, the observatory remained unused and began to deteriorate. Fortunately, it was about this same time that the City of Gaithersburg fomralized its historic perservation policies with the adoption of the Historic Preservation Ordinance and designated the observatory as its first officially designated historic site.

The National Oceanographic and Atmospheric Administraion (NOAA) conveyed the abandoned observatory tothe City for historic monument purposes in May 1987, after which the City granted an easment tot he Maryland Historical Trust. Funds were secured for the observatory's restoration and on December 20, 1989, it was deginated a National Historic Landmark. The Gaithersburg International Latitude Obseratory, its Meridian Mark Pier, and five monuments are listed on the National Register of Historic Places.
Erected 2011 by the City of Gaithersburg.
Location. 39° 8.202′ N, 77° 11.915′ W. Marker is in Gaithersburg, Maryland, in Montgomery County. Marker is on DeSellum Avenue. Touch for map. Marker is at or near this postal address: 100 DeSellum Ave., Gaithersburg MD 20877, United States of America.
Other nearby markers. At least 8 other markers are within walking distance of this marker. History and Purpose of the Gaithersburg Latitude Observatory (within shouting distance of this marker); The Meridian Mark Pier and Geodetic Survey Monuments (within shouting distance of this marker); Night at the Gaithersburg Latitude Observatory (within shouting distance of this marker); The Chandler Wobble (within shouting distance of this marker); General Edward Braddock (approx. mile away); DeSellum Family Cemetery (approx. 0.3 miles away); Schwartz House / City Hall Built 1895 (approx. 0.4 miles away); Summit Hall Farm (approx. 0.4 miles away). Touch for a list and map of all markers in Gaithersburg.
Also see . . .  The Observatory. (Submitted on July 16, 2012, by Allen C. Browne of Silver Spring, Maryland.)
Additional keywords. Geodesy
Categories. Science & Medicine
Credits. This page was last revised on June 16, 2016. This page originally submitted on July 1, 2012, by Allen C. Browne of Silver Spring, Maryland. This page has been viewed 276 times since then and 38 times this year. Photos:   1. submitted on July 1, 2012, by Allen C. Browne of Silver Spring, Maryland.   2. submitted on July 18, 2012, by Allen C. Browne of Silver Spring, Maryland. • Kevin W. was the editor who published this page.
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