ESO's Very Large Telescope Now Delivers Images Sharper Than Hubble (eso.org)

ffkom shares an excerpt from a press release via the European Southern Observatory: ESO's Very Large Telescope (VLT) has achieved first light with a new adaptive optics mode called laser tomography -- and has captured remarkably sharp test images of the planet Neptune, star clusters and other objects. The pioneering MUSE instrument in Narrow-Field Mode, working with the GALACSI adaptive optics module, can now use this new technique to correct for turbulence at different altitudes in the atmosphere. It is now possible to capture images from the ground at visible wavelengths that are sharper than those from the NASA/ESA Hubble Space Telescope. The combination of exquisite image sharpness and the spectroscopic capabilities of MUSE will enable astronomers to study the properties of astronomical objects in much greater detail than was possible before.

Comments

Aim it at the moon...

[Circlotron]

...and take pictures of the Apollo landing sites. That should shut a few mouths.

Re:Aim it at the moon...

[Anonymous Coward]

[1] MUSE and GALACSI in Wide-Field Mode already provides a correction over a 1.0-arcminute-wide field of view, with pixels 0.2 by 0.2 arcseconds in size. This new Narrow-Field Mode from GALACSI covers a much smaller 7.5-arcsecond field of view, but with much smaller pixels just 0.025 by 0.025 arcseconds to fully exploit the exquisite resolution.

tan( 0.025 arcseconds ) = 1.2120342e-7
distance to the moon is 384.4 million meters

1.2120342e-7 * 384.4e6 = 46.59 meters

tl;dr: Still about 2 orders of magnitude away from being able to take a blurry ass 15x20 pixel image of the lander. Try again in a few decades.

Re:Aim it at the moon...

[Zocalo]

And possibly damage the telescope too. The moon is vastly brighter than the kinds of things the VLT is meant to image, so if its optics and filters can't deal with that it would be bad. ISTR reading a response from one of the Hubble team on the question of what kind of images the telescope would produce if it were pointed at the Earth, and the response was basically a pure white frame because the amount of light captured, even at night, would overwhelm the telescope even at their fastest possible exposure settings, and would probably cause permanent damage as well.

Besides, which fake moon landings derp is going to accept the picture as genuine when they already discount the evidence provided by the laser reflectors left on the moon by three of the Apollo missions and two of the Soviet Lunakhod missions? The reflectors are still in use, so there's no reason why they couldn't acquire a suitable laser and bounce their own signal off them if they really wanted to, but then they'd need to discount their own evidence and it might detract from what this really is - a pathetically lame attempt to get some attention like those who claim the Earth is flat, so that's never going to happen.

Re:Aim it at the moon...

[Solandri]

A 15x20 pixel image of the Apollo lander (about 9 meters wide) would require an image resolution of 0.5 meters.

• arctan( 0.5 meters / 384.4 million meters ) = 0.00000000013 radians, or 0.00027 arc-seconds

The Rayleigh criterion then tells us that to resolve something that small using blue light (shortest wavelength) would require telescope optics that are:

• 1.22 * (450 nm) / ( 0.00000000013 radians) = 4.22 kilometers wide.

You might be able to do it with an interferometer. This is done all the time with radio telescopes - each dish acts as a single point on a very large mirror aimed at the same spot in the sky. But an interferometer needs to be aligned within a quarter wavelength of the light you're using. Relatively easy with radio waves, not so much with visible light.

Anyhow, this is all a moot point. The Apollo missions left retroreflectors on the landing sites. These are mirror arrays which will reflect light back exactly 180 degrees. Scientists use them all the time to precisely measure the distance to the moon, thus proving that we've actually been there.

Re:Slashdot, please help clean up Slashdot

[hcs_$reboot]

Funny how people reply to this obvious troll, like if it was a serious claim. Anyway we should keep AC posting as it is useful sometimes (and moderation does work).

Wasn't Hubble broken anyway?

[Qbertino]

IIRC they had to fly up and correct the lens with some contraption because someone/someteam had screwed up the numbers when building it.
Isn't that so?

Re:Wasn't Hubble broken anyway?

[Applehu Akbar]

IIRC the mirror was ground with gravity present. Then under zero G conditions it sprung back to an unanticipated shape.

No, Perkin-Elmer simply screwed up. And amazingly after finishing a 72-inch mirror and sending it into high orbit, they didn’t think of running the Foucault figure test that every amateur astronomer who has ever ground a mirror knows To do.

Re:Wasn't Hubble broken anyway?

[gmiller123456]

I had the pleasure of attending a lecture several years back by the then project manager for the Hubble. His explanation was that the issue was a managerial one. The instructions for one of the test devices were (summarized) drill a hole, then paint the device black. But what was actually done was it was painted black, then the hole was drilled. This issue was discovered early enough to fix. Apparently the standard process at the time was to have the project heads rotated ever so often so that they wouldn't get too cozy with each other, but the Hubble required these people to have access to highly classified information, limiting their ability to move people around. And the team was able to convince the manager not to make a big deal out of the out of order operation performed. And it was a tiny bur on that device that caused the test to be wrong.

Re:Slashdot, please help clean up Slashdot

[Joce640k]

Please Slashdot, can you stop all these trolls from polluting the Slashdot space. In the past the comments by users were of an interesting nature related to the subject story, but now on 5% maybe is about the story as trolls post rubbish about Politics, Defamation, Racist and such other crap....yada yada

You see that sliding bar thing at the top of the screen? Yeah, that one...

Hubble optical flaw origin

[sjbe]

IIRC the mirror was ground with gravity present. Then under zero G conditions it sprung back to an unanticipated shape.

Your recollection is incorrect. It was ground very precisely to the wrong shape due to some incorrectly assembled testing equipment. The problem was actually noted prior to launch but the test results were ignored. Gravity or the lack thereof had no relationship to the problem with the shape of the mirror. It was simply made to the wrong specifications and then final testing failed to catch the problem.

Re:Hubble optical flaw origin

[crunchygranola]

Also, you could test for the effects of gravity by turning it upside-down. If the mirror was still the right shape, then gravity is not an issue.

Ah, grasshopper. You fall for the very reasonable assumption that the Hubble was flown with an incorrectly figured mirror because no one on the ground could test it properly and find out that this was the case.

That isn't what happened.

When the mis-figuring was discovered by NASA, in orbit, I too was stunned. How could the engineers have relied on just one test to verify it?

They didn't.

The mirror was over-budget, and behind schedule, and management at Perkin-Elmer wanted to ship it. The mis-assembled instrument was the contractually agreed method of mirror acceptance, and the one used in the figuring process. When engineers found after the figuring that simple tests showed that it was incorrect, P-E management didn't care, and didn't tell NASA.

There were people at P-E who knew perfectly well that the mirror would not work. But hey, the managers probably got bonuses when the mirror left the facility.

Re:Slashdot, please help clean up Slashdot

[Ol Olsoc]

Funny how people reply to this obvious troll, like if it was a serious claim. Anyway we should keep AC posting as it is useful sometimes (and moderation does work).

Slashdot's moderation system does indeed work. And there is a level slider we can use to cut off anything below a certain level. Cut off anything below 1, and it cleans the neighborhood up right nicely.

Don't over minimize

[N3wsByt3]

Only partially true. Space-telescopes still have an advantage in some area's, especially for the deep and near-infrared wavelengths, and ultraviolet wavelengths, but the other advantages are becoming less and less obvious, especially if you consider the cost of both space-based as Earth-based telescopes.

The disturbances of the atmosphere - the major drawback (diffraction limit) up until the last decade of the 20th century - have become largely reduced thanks to adaptive optics and other technological advances.

The argument that we are now capable of constructing space-telescopes that are better than Hubble has no bearings on the comparative advances, since we can also create better earth-based telescopes than VLT, these days. As the Extremely Large Telescope will show, no doubt. There is little doubt this latter one will exceed the JWST, just as the VLT did with Hubble - IF the JWST was going for the visible light waves, which it isn't. In fact, it's the main reason Beryllium mirrors were used that excel in infra-red wavelengths, about the last advantage space-telescopes still have that warrant the vastly more expensive cost (now at more than 10 *billion* for the JWST, if I remember correctly).

Note that for that price, you could have made 10 Overwhelmingly Large Telescopes (OWL) which would completely DWARF the JWST on almost all other fronts, certainly when using interferometry.

Re:Don't over minimize

[ceoyoyo]

The diffraction limit is not due to atmospheric effects. It is a fundamental limit imposed by the aperture of your telescope, which is more or less the size of the primary mirror.

It's currently easier to make a large aperture telescope on the ground, but with the bigger ones it's hard to achieve the diffraction limit because of atmospheric effects. The very best adaptive optics only get you to Hubble territory. JWST is bigger than Hubble.

Interferometry, particularly image-forming interferometry, is probably easier in space. You've got all the space you could possibly want, you can use free space lasers instead of fibre optics, and you can arrange for your telescopes to move easily to produce the image; on the surface you need to put them on train tracks.

Technically, big mirrors are easier in space too, since they don't have to support themselves against gravity. The current problem is you have to get them up there.

One quibble

[Ol Olsoc]

Looking at the image of Neptune, all I have to say is Damn - this stuff works! Neptune is a good low contrast test of their adaptive optics system. And I'm going to have a blast today researching out the details of the badly named GALACSI system.

But seriously - if you are going to claim that your earth based adaptive optics system will deliver sharper images than Hubble - show us a comparison.

Its worth noting that Hubble is a flawed instrument in a good location, but the claim has been made, so stand and deliver, ESO!

Re:One quibble

[Raenex]

But seriously - if you are going to claim that your earth based adaptive optics system will deliver sharper images than Hubble - show us a comparison.

Try reading the article:

https://www.eso.org/public/uni...

Cool ESO video

[QuietLagoon]

ESO Chill 1 https://www.youtube.com/watch?... imo, worth watching.

Re: Slashdot, please help clean up Slashdot

[ArchieBunker]

In the past the trolls were funny and interesting. Natalie Portman and hot grits, the saga of OpenSourceMan, The Turd Report, even OGG THE CAVEMEN until the cops lock filter silenced him. Now its just APK and the anti trump guy.

Re: Slashdot, please help clean up Slashdot

[rogoshen1]

says someone posting as AC.

And no. requiring membership or taking away anonymity has a chilling effect.

The only way to have truly free speech and expression is the right to anonymity.