Very Long Baseline Array

The Very Long Baseline Array usually makes radio observations at wavelengths from three millimeters to 90 centimeters, or in other words, at frequencies from 0.3 gigahertz to 96 gigahertz. Within this frequency range, the VLBA observes in eight different frequency bands that are useful for radio astronomy. The VLBA also makes observations in two narrow radio bands below one gigahertz that include spectral lines produced by bright maser emissions.

The VLBA radio telescopes are located at:

{{Location map+ | USA

| width = 400

| caption = VLBA locations (red) and HSA locations (blue) in the contiguous United States

| places =

{{Location map~ | USA

| label = Hancock

| position =

| mark = Locator_Dot.png

| lat_deg = 42.93362

| lon_deg = -71.98681

}}

{{Location map~ | USA

| label = North Liberty

| position =

| mark = Locator_Dot.png

| lat_deg = 41.77165

| lon_deg = -91.574133

}}

{{Location map~ | USA

| label = Fort Davis

| position =

| mark = Locator_Dot.png

| lat_deg = 30.635214

| lon_deg = -103.944826

}}

{{Location map~ | USA

| label = Los Alamos

| position =

| mark = Locator_Dot.png

| lat_deg = 35.7752887

| lon_deg = -106.2455897

}}

{{Location map~ | USA

| label = Pie Town

| position = left

| mark = Locator_Dot.png

| lat_deg = 34.30107

| lon_deg = -108.11912

}}

{{Location map~ | USA

| label = Kitt Peak

| position =left

| mark = Locator_Dot.png

| lat_deg = 31.956253

| lon_deg = -111.612361

}}

{{Location map~ | USA

| label = Owens Valley

| position =

| mark = Locator_Dot.png

| lat_deg = 37.23176

| lon_deg = -118.27714

}}

{{Location map~ | USA

| label = Brewster

| position =bottom

| mark = Locator_Dot.png

| lat_deg = 48.13117

| lon_deg = -119.68325

}}

{{Location map~ | USA

| label = Green Bank

| position =right

| mark = Location dot blue.svg

| lat_deg = 38.255924

| lon_deg = -79.502341

}}

{{Location map~ | USA

| label = VLA

| position = bottom

| mark = Location dot blue.svg

| lat_deg = 34.079643

| lon_deg = -107.370591

}}

}}

{{Location map+ | World

| width = 400

| caption = VLBA locations (red) and HSA locations (blue) around the world

| places =

{{Location map~ | World

| label = St. Croix

| position =

| mark = Locator_Dot.png

| lat_deg = 17.75652

| lon_deg = -64.58376

}}

{{Location map~ | World

| label = Mauna Kea

| position =

| mark = Locator_Dot.png

| lat_deg = 19.80159

| lon_deg = -155.45581

}}

{{Location map~ | World

| label = Effelsberg

| position =

| mark = Location dot blue.svg

| lat_deg = 50.3130

| lon_deg = 6.53003

}}

}}

The use of the VLBA can be scheduled dynamically, and its sensitivity can be improved by a factor of five by including other radio telescopes such as the Green Bank Telescope in West Virginia, the Very Large Array (VLA) in New Mexico and the Effelsberg radio telescope in Germany. These three additional 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 (HSA).{{cite web|url=https://science.nrao.edu/facilities/vlba/HSA|title=High Sensitivity Array -- Science Website|first1=Amy|last1=Mioduszewski|first2=Justin|last2=Linford|date=2020-12-01|publisher=National Radio Astronomy Observatory|url-status=live|archive-url=https://web.archive.org/web/20210124220136/https://science.nrao.edu/facilities/vlba/HSA|archive-date=2021-01-24}} The Arecibo radio telescope in Puerto Rico was also used, before it collapsed.

File:Radio Telescope at Mauna Kea.jpg]]

Distance between each VLBA baseline (km):{{cite web|title=8 Angular Resolution & u-v Coverage|url=http://www.vlba.nrao.edu/astro/obstatus/2012-01-06/node24.html|first=Jon|last=Romney|date=2012-01-05|publisher=National Radio Astronomy Observatory}}

The longest baseline in the array is {{convert|8611|km|0}}.

• List of radio telescopes

{{Reflist|refs=

{{citation | first1=Swapan Kumar | last1=Saha | title=Aperture Synthesis: Methods and Applications to Optical Astronomy | series=Astronomy and Astrophysics Library | publisher=Springer | year=2010 | isbn=978-1-4419-5709-2 | page=81 | url=https://books.google.com/books?id=BIHe2Mmv08cC&pg=PA81 }}

}}

{{Commons category|VLBA}}

• {{Official website}}

{{Radio-astronomy}}

{{Authority control}}

Category:1993 establishments in the United States

Category:Interferometric telescopes

Category:Kitt Peak National Observatory

Category:Radio telescopes