Very Large Array

On my way from Show Low, Arizona to Albuquerque, New Mexico on Monday I made a side trip to visit the VLA, located west of Socorro, NM.  The VLA is part of the NRAO (National Radio Astronomy Observatory), which is funded largely by the National Science Foundation.  The NRAO operates several radio telescope facilities around the world.  The two largest facilities are located in Green Bank, West Virginia (right next to my mother’s hometown of Arbovale) and here near Socorro.  One of my uncles used to work as a telescope operator at Green Bank.  He would sit in a control room and move the scopes to point at various sources following a “script” of what, specifically, the scientists were monitoring each day (or night).

The VLA is a system of 27 identical 82-foot diameter radio telescopes.  These telescopes are available to scientists 24 hour a day, 362 days per year (they do not work on the 3 major holidays).



These radio telescopes (similar in design to satellite dishes used to receive TV signals) gather radio pulses from sources in deep space.  Scientists from all over the world submit proposals to the NRAO for projects they would like to study (these scopes have helped discover and research quasars, pulsars, black holes, etc).

By having multiple telescopes hooked in to one supercomputer scientists, in effect, are using a much larger single telescope which would be impossible to construct.  To achieve this, these 27 telescopes (3 groups of 9) can be moved to 4 different configurations in a ‘Y’ pattern on the desert floor.


They are moved from location to location on railroad tracks by a huge, orange transporter.




Once in position, their 3 legs are anchored to a concrete base and connected to the custom-made supercomputer by 2,700 miles of fiber-optic cable.  That computer is capable of making 16 quadrillion calculations per second in processing the radio signals into usable information.


In addition to the current positions you can see other concrete bases built to accommodate the scopes when they are moved to new positions.  These configurations range from a diameter of .62 mile up to 22.37 miles.


If you visit the VLA you will always see all 27 telescopes pointed at the same source.  In Green Bank there are 3 identical 85-foot diameter telescopes, one in a fixed location and the other two on wheels which can be moved up and down a paved runway, which serve the same function.  The telescopes are mounted equatorially, meaning they can pivot on one axis which is parallel to the axis on which the Earth rotates.  This allows the scopes to be pointed at a source in space when it rises above the horizon and track it across the sky until it drops below the opposite horizon.

There is a 28th scope which can serve as a replacement if one of the other scopes suffers technical problems.  It is stored in a maintenance facility they call “the Barn”.  All of the scopes are systematically moved to the Barn for routine maintenance and equipment upgrades.