Transition Transmission

In the Friday Foto, I introduced you to a distant shot of one of the satellite dishes of the VLA (Very Large Array). See here for information. The VLA is an interferometer; it operates by multiplying the data from each pair of telescopes together to form interference patterns. The structure of those interference patterns, and how they change with time as the earth rotates, reflect the structure of radio sources on the sky: we can take these patterns and use a mathematical technique called the Fourier transform to make maps. The 27 antennae were set up in the 70s at a cost of about $1 per taxpayer ($78,578,000 in 1972) and formal dedication took place in 1980. The VLA is used primarily by astronomers and for atmospheric/weather studies and other sciences.

When we drove down to Pie Town for my mother's birthday, we drove past the VLA and on the way back home we stopped for a visit.

To the left is the hanger where they work on the VLAs. Each antenna weighs 230 tons and stands 82 feet tall.

 This photo shows the size of the VLA. Did you notice my son and daughter standing in the gateway?

 

The 27 radio antennae are arranged in a Y-shaped configuration on the plains of San Agustin.

The antennae are arranged in four configurations, or arrays. There is an A array, B array, C array, and D array, varying in antenna separation of 1km to 36 km apart. At it's highest frequency of 43 GHz, a golf ball, with a high-power radio transmitter inside, can be seen 100 miles away.

Is there anybody out there?

Transition Transmission- song: TVC15, artist: David Bowie, album: StationtoStation