International Latitude Observatory
Encyclopedia
The International Latitude Observatories were a system of (originally) six observatories
located near the parallel of 39° 08' north latitude. They were used to measure the variation in latitude
that occurs as a result of the "wobble"
of the Earth
on its polar axis.
The original six observatories were located in:
of the Earth's axis, and its effect on measures of latitude. Six separate observatories were created along the parallel 39° 08' north latitude. The alignment of all six stations along the parallel helped the observatories to perform uniform data analysis. Twelve groups of stars were studied in the program, each group containing six pairs of stars. Each night, each station observed two of the star groups along a preset schedule and later compared the data against the measurements taken by the sister stations.
Economic difficulties and war caused the closings of some of the original stations, though a newer station was created in Uzbekistan after World War I
. The various stations continued to function until advances in computer technology and satellite observations rendered them obsolete in 1982. The data collected by the observatories over the years still has use to scientists, and has been applied to studies of polar motion, the physical properties of the Earth, climatology and satellite tracking and navigation.
The final six observatories were located, in order of Longitude (E to W), in:
Observatory
An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology are examples of disciplines for which observatories have been constructed...
located near the parallel of 39° 08' north latitude. They were used to measure the variation in latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
that occurs as a result of the "wobble"
Chandler wobble
The Chandler wobble is a small motion in the Earth's axis of rotation relative to the Earth's surface, which was discovered by American astronomer Seth Carlo Chandler in 1891. It amounts to on the Earth's surface and has a period of 433 days...
of the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
on its polar axis.
The original six observatories were located in:
- Gaithersburg, MarylandGaithersburg, MarylandGaithersburg is a city in Montgomery County, Maryland, United States. The city had a population of 59,933 at the 2010 census, making it the fourth largest incorporated city in the state, behind Baltimore, Frederick, and Rockville...
- Cincinnati, OhioCincinnati, OhioCincinnati is a city in the U.S. state of Ohio. Cincinnati is the county seat of Hamilton County. Settled in 1788, the city is located to north of the Ohio River at the Ohio-Kentucky border, near Indiana. The population within city limits is 296,943 according to the 2010 census, making it Ohio's...
- Ukiah, CaliforniaUkiah, CaliforniaThe average high temperature is 73.5 °F . Average low temperature is 46.1 °F . Temperatures reach 90 °F on an average of 65.6 days annually and 100 °F on an average of 14.4 days annually. Due to frequent low humidity, summer temperatures normally drop into the fifties at night. Freezing...
- Mizusawa, IwateMizusawa, IwateMizusawa was a city located in Iwate Prefecture, Japan.As of 2003, the city had an estimated population of 60,979 and a population density of 629.17 persons per km². The total area was 96.92 km².The city was founded on April 1, 1954....
, JapanJapanJapan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south... - Charjui, TurkestanTürkmenabatTürkmenabat , formerly and since the medieval times, Chardzhou , also spelled Çärjew, Chardjui, Charjou, Chardzhev, Charjev, Chärjew, or Charjew , ancient Amul, is a town in Turkmenistan, capital of Lebap Province...
- CarloforteCarloforteCarloforte is a fishing and resort town of located on Isola di San Pietro , approximately 7 km off the South Western Coast of Sardinia, Italy....
, ItalyItalyItaly , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
History
The International Polar Motion Service program was created by the United States Coast and Geodetic Survey in 1899 to study the precession, or "wobble"Chandler wobble
The Chandler wobble is a small motion in the Earth's axis of rotation relative to the Earth's surface, which was discovered by American astronomer Seth Carlo Chandler in 1891. It amounts to on the Earth's surface and has a period of 433 days...
of the Earth's axis, and its effect on measures of latitude. Six separate observatories were created along the parallel 39° 08' north latitude. The alignment of all six stations along the parallel helped the observatories to perform uniform data analysis. Twelve groups of stars were studied in the program, each group containing six pairs of stars. Each night, each station observed two of the star groups along a preset schedule and later compared the data against the measurements taken by the sister stations.
Economic difficulties and war caused the closings of some of the original stations, though a newer station was created in Uzbekistan after World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
. The various stations continued to function until advances in computer technology and satellite observations rendered them obsolete in 1982. The data collected by the observatories over the years still has use to scientists, and has been applied to studies of polar motion, the physical properties of the Earth, climatology and satellite tracking and navigation.
The final six observatories were located, in order of Longitude (E to W), in:
- Gaithersburg, Maryland, USA, Gaithersburg Latitude ObservatoryGaithersburg Latitude ObservatoryThe Gaithersburg Latitude Observatory, in Gaithersburg, Maryland is one of the system of six International Latitude Observatories and the only National Historic Landmark in Gaithersburg, Maryland. The building is in the National Register of Historic Places. The GLO was constructed by Edwin Smith,...
: N 39:08:12.51 W 77:11:55.85 - Cincinnati, Ohio, USA: N 39:08.3 W 84:25.4
- Ukiah, California, USA: N 39:08:14.26 W 123:12:42.54
- Mizusawa, Japan, National Institutes of Natural Sciences National Astronomical Observatory of JapanNational Astronomical Observatory of JapanThe is an astronomical research organisation comprising several facilities in Japan, as well as an observatory in Hawaii. It was established in 1988 as an amalgamation of three existing research organizations - the Tokyo Astronomical Observatory of the University of Tokyo, International Latitude...
, Mizusawa VERA Observatory: N 39:08.1 E 141:07.9 - Kitab, in UzbekistanUzbekistanUzbekistan , officially the Republic of Uzbekistan is a doubly landlocked country in Central Asia and one of the six independent Turkic states. It shares borders with Kazakhstan to the west and to the north, Kyrgyzstan and Tajikistan to the east, and Afghanistan and Turkmenistan to the south....
: N 39:08.0 E 66:52.9 - Carloforte, Italy: N 39:08:13.76 E 8:18:41.90
External links
- National Park Service - The history of the Gaithersburg Observatory in Maryland, and the overall project.