NYT on the Very Large Array

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.'"

Oops

[hackwrench]

When I first read that I thought it just said Mexico, not New Mexico... but it does say that Mexico is paying for some of it...

Anyhow...

Re:Hmm...

[hackwrench]

What have I done that would cause me to be phased out by evolution?

Some of my perspective...

[hackwrench]

My previous post would have done better with the subject 'Is evolution gunning for me?'. Too bad I didn't think of it before I posted. The reaction to my earlier post got me to thinking that the poster thought I was racist. That is far from the truth. I am merely acting from the belief that a united humanity acting within a united Earth sphere, with a government acting in its interests will achieve more for itself that it would divided. Based on the evedence provided in my earlier posts and with the further evidence that many Mexicans think that part of the United States belongs to them [google.com] anyways, as well as the fact that many Mexicans want to contribute to the United States economy, it seems like it might be a ripe time for the integration of the two.

Re:Tower of Babel

[Atrahasis]

No, He confused their tongues, and created differing languages, to confound their plans to build a tower to the heavens, fo rif they could do that, then nothing would be impossible for them.

I don't see where destruction or world government come into it.

Why a Merger By U.S. Takeover

[hackwrench]

The main reason I'm suggesting the merger be done by the U.S is because it doesn't seem likely that it will be done by mutual consent, and recent events seem to favor that manner if a merger were to be done at all. I am reminded of a post somewhere suggesting that the U.S. rejoin the British Empire.

VLA

[ObviousGuy]

unsigned long double foo[1000000];

Haha!

Interferometers, and a possible correction

[dpp]

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 [cam.ac.uk] at MRAO [cam.ac.uk] 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.

Re:Interferometers, and a possible correction

[cperciva]

"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.

In the context of athmospheric interference, isn't the real benefit of VLA that it becomes possible to see the equally fine details on longer wavelengths? Normally the frequency and resolution are inversely proportional, but I'd expect the athmosphere to impose a limit on the resolution independant of wavelength.

Of course I might be completely wrong here, since I'm neither an astronomer nor an optical engineer, and it's 8AM right now.

Re:Interferometers, and a possible correction

[dpp]

In the context of athmospheric interference, isn't the real benefit of VLA that it becomes possible to see the equally fine details on longer wavelengths? Normally the frequency and resolution are inversely proportional, but I'd expect the athmosphere to impose a limit on the resolution independant of wavelength.

Once you get to radio wavelengths, things are quite different from in the optical; for example, radio telescopes at longer wavelengths can often see through cloud. The limiting factor is the diffraction due to the maximum size of the telescope (or radio interference of human origin) rather than the seeing.

You're right, though, that as we go to the much longer radio wavelengths from the optical, we need much larger telescopes in order to keep the same angular resolution.

I hope the above is reasonably accurate... it's late at night here!

Re:Yay

[dpp]

Maybe I'm being trolled :-), but this isn't the same thing as SETI@home [berkeley.edu] , just because the VLA is a radio telescope.

Radio astronomy [cam.ac.uk] lets us study objects like supernova remnants and the interstellar medium (and hence star-birth and star-death), or active galaxies such as quasars, and the big cosmological questions about the origin of the universe.

The VLA is no more 'looking for aliens with radios' than optical telescopes are 'looking for aliens with flashlights'.

Re:Yay

[Gogo Dodo]

Seti@Home uses data from the Arecibo radio telescope [berkeley.edu], not the VLA.

At least flame the right radio telescope.

Registration-Free Link

[RobHornick]

http://www.majcher.com/nytview.html?url=2002/06/18 / cience/space/18ARRA.html&submit [majcher.com] - Rob

Gorgeous pic of VLA from APOD

[texchanchan]

Here's a beautiful photo [nasa.gov] of the VLA from Astronomy Picture of the Day [nasa.gov].