Very Long Baseline Array

The Very Long Baseline Array (VLBA) is a system of ten radio telescopes controlled remotely from the Array Operations Center in Socorro, New Mexico (USA) by the National Radio Astronomy Observatory. The array works together as the world's largest dedicated, full-time astronomical instrument using the technique of very long baseline interferometry. 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-foot (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 tonnes (240 tons) and is nearly as tall as a ten story building when pointed straight up. The longest baseline in the array is 8,611 kilometres (5,351 mi).

The VLBA radio telescopes are located at:

Toponymy	U.S. state	Geographic coordinate system
St. Croix	U.S. Virgin Islands		SC
Hancock	New Hampshire		HN
North Liberty	Iowa		NL
Fort Davis	Texas		FD
Los Alamos	New Mexico		LA
Pie Town	New Mexico		PT
Kitt Peak	Arizona		KP
Owens Valley	California		OV
Brewster	Washington		BR
Mauna Kea	Hawaii		MK

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.^[1] These sites, with coordinates, are as follows:

Toponymy	State	Geographic coordinate system
Arecibo	Puerto Rico		AR
Green Bank	West Virginia		GB
Very Large Array	New Mexico		Y27
Effelsberg	Germany		EB

Contents 1 Baseline distance and angular resolution 2 See also 3 References 4 External links

Baseline distance and angular resolution

Distance between each VLBA baseline (km):^[2]

	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

See also

• List of radio telescopes

References

External links

• Official site

Radio astronomy Category:Radio telescopes Main articles Astronomical interferometer Very Long Baseline Interferometry (VLBI) Radio telescope Radio window Astronomical radio source Notable radio telescopes Single dish Arecibo Observatory (Puerto Rico) Effelsberg Telescope (Germany) Large Millimeter Telescope (Mexico) Yevpatoria RT-70 (Ukraine) Galenki RT-70 (Russia) Suffa RT-70 (Uzbekistan) Green Bank Telescope (West Virginia, USA) Lovell Telescope (UK) Parkes Observatory (Australia) Interferometers Australia Telescope Compact Array (ATCA, Australia) Allen Telescope Array (ATA, California, USA) Combined Array for Research in Millimeter-wave Astronomy (CARMA, California, USA) European VLBI Network (Europe) Giant Metrewave Radio Telescope (GMRT, India) Low Frequency Array (LOFAR, Netherlands) Multi-Element Radio Linked Interferometer Network (MERLIN, UK) Molonglo Observatory Synthesis Telescope (MOST, Australia) One-Mile Telescope (UK) Very Large Array (VLA, New Mexico, USA) Very Long Baseline Array (VLBA, USA) Westerbork Synthesis Radio Telescope (WSRT, Netherlands) Proposed / under construction Five-hundred-meter Aperture Spherical Telescope (FAST, China) Atacama Large Millimeter Array (ALMA, Chile) Australian Square Kilometre Array Pathfinder (ASKAP, Australia) Murchison Widefield Array (MWA, Australia) MeerKAT South Africa Primeval Structure Telescope (PaST, China) Square Kilometre Array (SKA, tbd) Observatories Algonquin Radio Observatory (Canada) Haystack Observatory (USA) Jodrell Bank Observatory (UK) Mullard Radio Astronomy Observatory (UK) National Radio Astronomy Observatory (USA) Onsala Space Observatory (Sweden) Special Astrophysical Observatory of the Russian Academy of Science (SAORAS, Russia) People Edward George Bowen Arthur Covington Antony Hewish Karl Guthe Jansky Bernard Lovell Jan Oort Joseph Lade Pawsey Ruby Payne-Scott Grote Reber Martin Ryle Related articles Cosmic microwave background radiation SETI Interferometry Radio propagation Aperture synthesis Wow! signal Optical astronomy Submillimetre astronomy Infrared astronomy High-energy astronomy