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NYT on the Very Large Array

Posted by michael on from the descriptive-names-a-plus dept.

jonerik writes "Today's New York Times has this article on the current renovation of the Very Large Array; the Y-shaped collection of 27 movable large dish antennas in New Mexico that are collectively one of the most important radio telescope systems in the world. The Times article details plans currently underway to upgrade the system with new electronics, as well as the eventual addition of eight more telescopes to the array. 'The planned renovation is scheduled to be completed in 2011. The National Science Foundation, the observatory's principal supporter, will pay for most of the $75 million project, with smaller amounts coming from Canada and Mexico.'"

2 of 28 comments (clear)

  1. Interferometers, and a possible correction by dpp · · Score: 5, Informative

    The VLA is an interferometer, which means that the 27 individual dishes are linked to simulate one huge telescope as big as the largest distance between them (up to 36km). This process of 'aperture synthesis' was pioneered at MRAO in Cambridge, UK (where I used to study, hence the plug :-).

    Very roughly speaking, you 'fill in' the gaps in your notional huge telescope by having multiple dishes, sometimes by moving them, and also by allowing the Earth to rotate (thus effectively moving the dishes around for you over the course of a day). The larger the separation between the most distant dishes, the finer the resolution. However, you don't have the collecting area of an actual 36-km telescope, which can limit the sensitivity to faint objects.

    So, strictly speaking, where the NYT article says:

    Even though there is plenty of room here for more antennas, astronomers want to place the new ones some 60 and 150 miles away in southwestern New Mexico. With the wider dispersion, affording deeper views of the heavens, the Very Large Array will be, in effect, a single telescope the size not of a desert plain, but a quarter of a state.

    they aren't quite accurate. "Deeper" is usually taken to mean "able to see fainter objects", whereas the longer baselines ("wider dispersion") will actually be allowing the VLA to see finer details instead.

    --
    This post is strictly my own opinion and not necessarily that of my employer.
  2. Gorgeous pic of VLA from APOD by texchanchan · · Score: 4, Informative

    Here's a beautiful photo of the VLA from Astronomy Picture of the Day.