ALMA Telescope Makes First Observations

Article written: 17 Nov , 2009
Updated: 24 Dec , 2015

The ALMA telescope located high in the Chilean Andes made its first measurements on Tuesday using just two of the eventual 66 antennas that will comprise the array. The Atacama Large Millimeter/submillimeter Array took interferometric measurements of radio signals, or “fringes,” from a distant quasar (3C454.3) at sub-millimeter wavelengths. Astronomers said the data from the two 12-meter antennas provided unprecedented sensitivity and resolution, and observations at a wavelength of less than 1mm showed ALMA was now truly a “submillimeter” as well as millimeter-wave telescope.

ALMA is the largest, most ambitious ground-based observatory ever created, with completion slated for 2012. When all 66 antennas are working in synch, researchers believe ALMA will revolutionize the way we see the universe, probing deep into some of the first galaxies to form after the Big Bang and observing planets in mid-formation around young stars.

Interferometry involves linking together arrays of smaller telescopes to make measurements of an object. Sophisticated electronic systems will correlating the signals.

The next step in the process will be the addition of a third antenna which will allow the Alma team to obtain “phase closure.” This is an important capability which requires at least three antennas to cancel out errors in the “phase” of the signals caused by the instruments themselves and by the Earth’s atmosphere.

Here’s a video overview of ALMA:

Source: BBC

Nancy Atkinson is currently Universe Today’s Contributing Editor. Previously she served as UT’s Senior Editor and lead writer, and has worked with Astronomy Cast and 365 Days of Astronomy. Nancy is the author of the new book “Incredible Stories from Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos.” She is also a NASA/JPL Solar System Ambassador.

5 Responses

  1. Astrofiend says

    Sweet mother of awesome – super keen for this beast to start paying dividends…

  2. ND says

    Didn’t even know this was being built. Nice little surprise 🙂

  3. DrFlimmer says

    Is there information available, what object they targeted? Is this probably mentioned in the video (I don’t want to watch it, now 😉 )?

  4. It was quasar 3C454.3. Sorry, meant to have that in the article, and now its been added. Thanks!

  5. Jon Hanford says

    The ALMA homepage ( ) mentions that additionally the Orion Molecular Cloud and quasar 3C 84 as well as 3C 454.3 were detected with these initial two antennae and provide more detailed comments on these ‘first fringes’ observations. Something to *really* look forward to in 2012. 🙂

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