Six Optical Telescopes Combined Into One

00Paddy writes: "Starstuff.org reports on how astronomers successfully combined the light from six independent telescopes to form a single, high-resolution image of a distant multiple-star system using interferometry techniques. The combined telescopes gives a effective mirror diameter of 430 meters, much bigger than any single mirror could be made. This technology will lead to images of sunspots of distant stars and maybe images Jupiter-sized planets orbiting distant stars."

Slightly dodgy link

[Fweeky]

Notice it includes ?rated=5 - that means all /. readers who use that URL will give it a rating of 5 out of 6.

Way to mess up their stats :)

It also links directly to the article, which will instantly reload you to the frameset. A better URL is http://www.starstuff.org/default.asp?cover=/articl es/1087.asp [starstuff.org], which won't make you vote for anything and which won't cause the entire thing to refresh into a frameset the instant it loads.

Re:Slightly dodgy link

[waytoomuchcoffee]

Or even better, go to the Project Page [navy.mil] itself.

Re:Slightly dodgy link

[ChadN]

Who the hell actually reads the linked-to articles?

Whay can't this be done on a planet scale?

[Anonymous Coward]

If you can make a 430-meter diameter telescope in this way, why can't a 10,000-meter diameter telescope be made by doing the same thing with hundreds or thousands of telescopes all across a hemisphere?

Re:Whay can't this be done on a planet scale?

[Christopher Thomas]

If you can make a 430-meter diameter telescope in this way, why can't a 10,000-meter diameter telescope be made by doing the same thing with hundreds or thousands of telescopes all across a hemisphere?

Because you need a direct optical link between the telescopes, and because you want the mirror setup you use for this to be as stable as possible (relative motion will change path lengths and muck up your image reconstruction).

You can get around this with radio telescopes because you can sample and timestamp the received signals with timing resolution much finer than the period of the radio waves. To do this with light, we'd need light sensors and electronics at least a million times faster than we have now, and atomic clocks based on mid-UV light instead of microwaves).

A giant interferometer could be built in space, of course.

Re:Whay can't this be done on a planet scale?

[Anonymous Coward]

You can get around this with radio telescopes because you can sample and timestamp the received signals with timing resolution much finer than the period of the radio waves.

Measuring the wave collapses the wave function. Measuring then combining is not the same as combining THEN measuring. Those radio telescope arrays can't be called true interferometers.

Re:Whay can't this be done on a planet scale?

[Christopher Thomas]

You can get around this with radio telescopes because you can sample and timestamp the received signals with timing resolution much finer than the period of the radio waves.

Measuring the wave collapses the wave function. Measuring then combining is not the same as combining THEN measuring. Those radio telescope arrays can't be called true interferometers.

Come again?

An interferometer is a classical device. I only have to worry about waveform collapses if I'm counting individual photons.

Re:Whay can't this be done on a planet scale?

[astroboscope]

This is one of the differences between radio and optical interferometers: radio signals have so many more photons for the same same flux that they are indistingushable from waves (and they can be amplified, so there are plenty of photons to go around for comparisons). At higher frequencies the number of photons drops, and quantum effects are important and problematic.

Re:Whay can't this be done on a planet scale?

[Smitty825]

There appears to be a project like this going on right now. I can't find the link for product info right now, but some schools (University of Georgia, and Cal Tech IIRC) are placing a large number (again, can't find the link) of 1 meter telescopes up in the hills around the Mount Wilson Observetory.

It's on the Mount Wilson [mtwilson.edu] webpage, but that appears to be down right now. Also, for some extra geek/slashdot points, they appear to be doing all of this with some sort of linux distro...

If I can find it, I'll post a reply to this message...

Re:Whay can't this be done on a planet scale?

[Smitty825]

Ah, ha! I found it :-)

See the CHARA site here [gsu.edu]

Re:Whay can't this be done on a planet scale?

[Nyphur]

... It can. Just because something can be done, and should be done, it is not nececarilly done. There are a lot fo limiting factors involved :(

Hm..

[ThatComputerGuy]

funny how so many articles on /. can be related to clusters...

50 Meters not 430.

[RandomInAction]

You posted
combined telescopes gives a effective mirror diameter of 430 meters, much bigger than any single mirror could be made.

From the article:
This level of detail would require a single monolithic telescope mirror in excess of 50 meters in diameter.
and,
In the near future, NPOI will be commissioning all of the remaining stations onto which any of the six telescopes can be mounted for a maximum array size of 430 meters, the largest baseline of all current imaging interferometer projects.

Nevertheless this is an exciting technique.

Old News... +Moon Observatory

[Nyphur]

This is old news. They used that system over 5 years ago to discover that that exact star was, in fact, two stars. Explained the brightness of it. But I have to point out that this IS REALLY OLD news.

On a more constructive point, the best course of action now would probably be to make a similar system on the "dark" side of Luna, the planet Earth's moon because, as was noted several years ago, the further apart the telescopes are, the better resolution and clarity you would get, though you might need to introduce more for accuracy. It would be much better thant eh hubble telescope, most would admit, though it isn't stationary.