The Very Long Baseline Array (VLBA) is a system of ten radio telescope

Radio telescope

A radio telescope is a form of directional radio antenna used in radio astronomy. The same types of antennas are also used in tracking and collecting data from satellites and space probes...

s controlled remotely from the Array Operations Center

Array Operations Center

The Array Operations Center in Socorro, New Mexico, is the control and monitor centre for the VLBA and the VLA. From the AOC, NRAO operators are able to remotely control and monitor the remote stations over the internet. The operators can aim the antennas, select radio frequencies for observation,...

 in Socorro

Socorro, New Mexico

Socorro is a city in Socorro County in the U.S. state of New Mexico. It stands in the Rio Grande Valley at an elevation of . The population was 9,051 at the 2010 census...

, New Mexico

New Mexico

New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

 (USA) by the National Radio Astronomy Observatory

National Radio Astronomy Observatory

The National Radio Astronomy Observatory is a Federally Funded Research and Development Center of the United States National Science Foundation operated under cooperative agreement by Associated Universities, Inc for the purpose of radio astronomy...

. The array works together as the world's largest dedicated, full-time astronomical instrument using the technique of very long baseline interferometry

Very Long Baseline Interferometry

Very Long Baseline Interferometry is a type of astronomical interferometry used in radio astronomy. It allows observations of an object that are made simultaneously by many telescopes to be combined, emulating a telescope with a size equal to the maximum separation between the telescopes.Data...

. Its construction began in February 1986, and was completed in May 1993. The first observation using all ten sites occurred on May 29, 1993. The total construction cost was US$85 million.

Each VLBA station consists of an 82 feet (25 m) diameter dish antenna and an adjacent control building which houses the station computer, tape recorders and other equipment associated with collecting the radio signals gathered by the antenna. Each antenna weighs 218 tonne and is nearly as tall as a ten story building when pointed straight up. The longest baseline in the array is 8611 kilometres (5,351 mi).

The VLBA radio telescopes are located at:

• Mauna Kea
  Mauna Kea
  Mauna Kea is a volcano on the island of Hawaii. Standing above sea level, its peak is the highest point in the state of Hawaii. However, much of the mountain is under water; when measured from its oceanic base, Mauna Kea is over tall—significantly taller than Mount Everest...
  
  , Hawaii
  Hawaii
  Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
  
   (19°48′04.97"N 155°27′19.81"W) MK
• Brewster, Washington
  Brewster, Washington
  Brewster is a city in Okanogan County, Washington, United States. The population was 2,370 at the 2010 census.-History:In 1811, John Jacob Astor's Pacific Fur Company established Fort Okanogan just north of the present site of Brewster, which was the first American post in Washington...
  
   (48°07′52.42"N 119°40′59.80"W) MR
• Owens Valley
  Owens Valley
  Owens Valley is the arid valley of the Owens River in eastern California in the United States, to the east of the Sierra Nevada and west of the White Mountains and Inyo Mountains on the west edge of the Great Basin section...
  
  , California
  California
  California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
  
   (37°13′53.95"N 118°16′37.37"W) OV
• Kitt Peak
  Kitt Peak
  Kitt Peak is a mountain in the U.S. state of Arizona. It is the location of the Kitt Peak National Observatory. The radio telescope at the Observatory is one of ten dishes comprising the Very Long Baseline Array ....
  
  , Arizona
  Arizona
  Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
  
   (31°57′22.70"N 111°36′44.72"W) KP
• Pie Town
  Pie Town, New Mexico
  Pie Town is an unincorporated town on U.S. Route 60 in Catron County, New Mexico, United States. Its name comes from a dried-apple pie business that was established by Clyde Norman in the early 1920s. Pie Town hosts a Pie Festival on the second Saturday of each September...
  
  , New Mexico
  New Mexico
  New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
  
   (34°18′03.61"N 108°07′09.06"W) PT
• Los Alamos, New Mexico
  Los Alamos, New Mexico
  Los Alamos is a townsite and census-designated place in Los Alamos County, New Mexico, United States, built upon four mesas of the Pajarito Plateau and the adjoining White Rock Canyon. The population of the CDP was 12,019 at the 2010 Census. The townsite or "the hill" is one part of town while...
  
   (35°46′30.45"N 106°14′44.15"W) LA
• Fort Davis, Texas
  Fort Davis, Texas
  Fort Davis is a census-designated place in Jeff Davis County, Texas, United States. The population was 1,050 at the 2000 census and 1,041 according to a 2007 estimate. It is the county seat of Jeff Davis County...
  
   (30°38′06.11"N 103°56′41.32"W) FD
• North Liberty, Iowa
  North Liberty, Iowa
  North Liberty is a city in Johnson County, Iowa, United States. It is a suburb of Iowa City and part of the Iowa City Metropolitan Statistical Area....
  
   (41°46′17.13"N 91°34′26.88"W) NL
• Hancock, New Hampshire
  Hancock, New Hampshire
  Hancock is a town in Hillsborough County, New Hampshire, United States. The population was 1,654 at the 2010 census. Hancock is home to the Welch Family Farm Forest....
  
   (42°56′00.99"N 71°59′11.63"W) HN
• St. Croix, United States Virgin Islands
  United States Virgin Islands
  The Virgin Islands of the United States are a group of islands in the Caribbean that are an insular area of the United States. The islands are geographically part of the Virgin Islands archipelago and are located in the Leeward Islands of the Lesser Antilles.The U.S...
  
   (17°45′23.68"N 64°35′01.07"W) SC

Four other sites are brought online for as much as 100 hours per four-month trimester. In this configuration, the entire array is known as the High-Sensitivity Array. These sites, with coordinates, are as follows:

• Arecibo
  Arecibo
  Arecibo may refer to:*Arecibo, Puerto Rico, a municipality located by the Atlantic Ocean*Arecibo Observatory, a very sensitive radio telescope located approximately south-southwest from the city of Arecibo...
  
  , Puerto Rico
  Puerto Rico
  Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
  
   (18°20′36.60"N 66°45′11.10"W) AR
• Green Bank
  Green Bank, West Virginia
  Green Bank is a census-designated place in Pocahontas County in West Virginia's Potomac Highlands inside the Allegheny Mountain Range. Green Bank is located along WV 28. Green Bank is also close to the Snowshoe Mountain ski resort...
  
  , West Virginia
  West Virginia
  West Virginia is a state in the Appalachian and Southeastern regions of the United States, bordered by Virginia to the southeast, Kentucky to the southwest, Ohio to the northwest, Pennsylvania to the northeast and Maryland to the east...
  
   (38°25′59.24"N 79°50′23.41"W) GB
• Very Large Array
  Very Large Array
  The Very Large Array is a radio astronomy observatory located on the Plains of San Agustin, between the towns of Magdalena and Datil, some fifty miles west of Socorro, New Mexico, USA...
  
  , New Mexico
  New Mexico
  New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
  
   (34°04′43.75"N 107°37′05.91"W) Y27
• Effelsberg
  Effelsberg
  The Effelsberg 100-m Radio Telescope is a radio telescope in the Ahrgebirge in Bad Münstereifel, district of Euskirchen, North Rhine-Westphalia, Germany.- Geography :...
  
  , Germany
  Germany
  Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
  
  (50°31′30"N 6°53′00.3"E) EB

Baseline distance and angular resolution

Distance between each VLBA baseline (km):

	SC	HN	NL	FD	LA	PT	KP	OV	BR	MK	EB	AR	GB	Y27
SC	...	2853	3645	4143	4458	4579	4839	5460	5767	8611	6822	238	2708	4532
HN	2853	...	1611	3105	3006	3226	3623	3885	3657	7502	5602	2748	829	3198
NL	3645	1611	...	1654	1432	1663	2075	2328	2300	6156	6734	3461	1064	1640
FD	4143	3105	1654	...	608	564	744	1508	2345	5134	8084	3922	2354	515
LA	4458	3006	1432	608	...	236	652	1088	1757	4970	7831	4246	2344	226
PT	4579	3226	1663	564	236	...	417	973	1806	4795	8014	4365	2551	52
KP	4839	3623	2075	744	652	417	...	845	1913	4466	8321	4623	2939	441
OV	5460	3885	2328	1508	1088	973	845	...	1214	4015	8203	5255	3323	1025
BR	5767	3657	2300	2345	1757	1806	1913	1214	...	4398	7441	5585	3326	1849
MK	8611	7502	6156	5134	4970	4795	4466	4015	4398	...	10328	8434	7028	4835
EB	6822	5602	6734	8084	7831	8014	8321	8203	7441	10328	...	6911	6335	8008
AR	238	2748	3461	3922	4246	4365	4623	5255	5585	8434	6911	...	2545	4317
GB	2708	829	1064	2354	2344	2551	2939	3323	3326	7028	6335	2545	...	2516
Y27	4532	3198	1640	515	226	52	441	1025	1849	4835	8008	4317	2516	...

Minimum angular resolution:

Wavelength (cm)	90	50	21	18	13	6	4	2	1	0.7
(mas)	22	12	5.0	4.3	3.2	1.4	0.85	0.47	0.32	0.17