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Magellan II's Adaptive Optics Top Hubble's Resolution

timothy posted about a year ago | from the no-longer-a-whole-lot-of-shakin'-goin'-on dept.

Space 136

muon-catalyzed writes "The incredible 'first light' images captured by the new adaptive optics system called Magellan|AO for "Magellan Adaptive Optics" in the Magellan II 6.5-meter telescope are at least twice as sharp in the visible light spectrum as those from the NASA's Hubble Space Telescope. 'We can, for the first time, make long-exposure images that resolve objects just 0.02 arcseconds across — the equivalent of a dime viewed from more than a hundred miles away,' said Laird Close (University of Arizona), the project's principal scientist. The 6.5-meter Magellan telescopes in the high desert of Chile were widely considered to be the best natural imaging telescopes in the world and this new technology upgraded them to the whole new level. With its 21-foot diameter mirror, the Magellan telescope is much larger than Hubble with its 8-foot mirror. Until now, Hubble always produced the best visible light images, since even large ground-based telescope with complex adaptive optics imaging cameras could only make blurry images in visible light. The core of the new optics system, the so-called Adaptive Secondary Mirror (ASM) that can change its shape at 585 points on its surface 1,000 times each second, counteracts the blurring effects of the atmosphere."

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Nice Summary (-1)

Anonymous Coward | about a year ago | (#44641733)

Is it me, or is that summary incredibly difficult to read?

Re:Nice Summary (1)

Aguazul2 (2591049) | about a year ago | (#44641807)

Is it me, or is that summary incredibly difficult to read?

Try again after a cup of coffee.

Re:Nice Summary (2)

Cryacin (657549) | about a year ago | (#44641867)

I suspect it will take a bit more than coffee.

Re:Nice Summary (1)

FatdogHaiku (978357) | about a year ago | (#44643147)

I suspect it will take a bit more than coffee.

Try adding just a touch of Ketamine, it takes that caffeine jitter away...
CAUTION:
Ketamine is not intended for use by humans and may be unlawful in your area. Additionally, some people do experience the side effect of waking up with their pants around their ankles.

Re: Nice Summary (0)

Anonymous Coward | about a year ago | (#44641815)

It's you. It wasn't dummed-down, and nearly everything is these days.

Re: Nice Summary (0)

Anonymous Coward | about a year ago | (#44641865)

I meant "dumbed".

Sorry.

it's like rain on your wedding day (1)

Anonymous Coward | about a year ago | (#44642371)

It wasn't dummed-down, and nearly everything is these days.

stay FUCKING AWSOME Anonymous Coward!

Re:it's like rain on your wedding day (1)

Agent0013 (828350) | about a year ago | (#44645393)

Did you intend to misspell awesome?

Re:Nice Summary (1)

ciderbrew (1860166) | about a year ago | (#44641837)

I found it easy to read and don't feed the trolls!

Re:Nice Summary (1)

rossdee (243626) | about a year ago | (#44641987)

"The 6.5-meter Magellan telescopes in the high desert of Chile were widely considered to be the best natural imaging telescopes in the world "

WTF is natural imaging ?

Are other telescopes unnatural ?

Re:Nice Summary (1)

Twanfox (185252) | about a year ago | (#44642111)

They probably meant 'natural' as in 'direct imaging', instead of post-capture image processing to correct artifacts.

Re:Nice Summary (1)

jkflying (2190798) | about a year ago | (#44642221)

I think they're referring to visible light, not radio, IR, UV or X-Ray.

Re: Nice Summary (1)

superzerg (1523387) | about a year ago | (#44643057)

I think naturel imaging is used to rules out interferometry

Re:Nice Summary (0)

Anonymous Coward | about a year ago | (#44642127)

Is it me, or is that summary incredibly difficult to read?

Perhaps you need to adapt your optics? E.g. with reading glasses?

Re:Nice Summary (0)

Anonymous Coward | about a year ago | (#44642749)

Maybe if you had used the Magellan II telescope instead of the Hubble telescope to read it, it would have been clearer

Re:Nice Summary (1)

Palamos (1379347) | about a year ago | (#44646953)

It's you.

Still can't handle proper units? (2)

Russ1642 (1087959) | about a year ago | (#44641827)

Right in the summary we have a comparison between the 6.5 m Magellan telescope and the 8 ft Hubble.

Re:Still can't handle proper units? (2, Informative)

Anonymous Coward | about a year ago | (#44641927)

Well, the sentence where they compare the two is already converted to similar units, so it doesn't hurt my brain. YMMV

Re:Still can't handle proper units? (1, Offtopic)

Russ1642 (1087959) | about a year ago | (#44641999)

My point is that they are mixing units together. Just pick one system, SI, and stick to it. If you can make it a whole paragraph without screwing that up then you get a gold star.

Re:Still can't handle proper units? (2)

krlynch (158571) | about a year ago | (#44643285)

Why? We switch units all the time, even when doing this "science" thing that so many seem to think only uses SI: eV, barn, torr, atm, etc. Suck it up, and learn to do conversions....

Re:Still can't handle proper units? (0)

Anonymous Coward | about a year ago | (#44644021)

Why? We switch units all the time, even when doing this "science" thing that so many seem to think only uses SI: eV, barn, torr, atm, etc. Suck it up, and learn to do conversions....

Don't let him know about Gaussian units or the fact that theorist like to do things like normalize away all the units. Or that astro physicists (relevant to this story) measure lengths in parsecs which isn't an SI unit.

Re:Still can't handle proper units? (0)

Anonymous Coward | about a year ago | (#44645125)

Why? We switch units all the time, even when doing this "science" thing that so many seem to think only uses SI: eV, barn, torr, atm, etc. Suck it up, and learn to do conversions....

Don't let him know about Gaussian units or the fact that theorist like to do things like normalize away all the units. Or that astro physicists (relevant to this story) measure lengths in parsecs which isn't an SI unit.

Yeah, those astrophysicists are always going on about Magellan's 2.1E-16 parsec diameter mirror.

Re:Still can't handle proper units? (1)

dywolf (2673597) | about a year ago | (#44643803)

I'd bet because the Magelen was specced in SI, and the Hubble wasn't. so the origianl source material that was snipped and molded into a submission has a conflict that the submitter deflated by adding the 21 to 8 comparison sentence.

Re:Still can't handle proper units? (1, Funny)

Immerman (2627577) | about a year ago | (#44642037)

Hey, the whole point of using US customary units is to be kooky and incompatible right? Mixing units just makes it even better. Now if you'll excuse me I need to add a pint of lemon juice and a few liters of cream to this hogshead of soup I'm making.

Re:Still can't handle proper units? (2, Interesting)

hedwards (940851) | about a year ago | (#44643027)

The whole point of using Imperial units is that we don't want to throw out trillions of dollars worth of infrastructure to make the Europeans happy. Seriously, spend a year in the US with our measures and spend a year somewhere that uses metric measures; metric isn't any easier for any thing you're likely to be doing on a day to day basis. Unless of course you're a scientist or engineer.

Re:Still can't handle proper units? (2)

hedwards (940851) | about a year ago | (#44643209)

I love how the pro-Metric people mod me down, rather than posing a substantive reason for doing it.

I know the metric system, I've used the metric system and it contributes absolutely nothing in daily living. None of the conversions that it's optimized for occur in daily living with any regularity, whereas I regularly need half of something or 2x as much of it.

Re:Still can't handle proper units? (0)

Anonymous Coward | about a year ago | (#44644059)

Same thing for imperial units, it contributes absolutely nothing in daily living.

The metric system is still useful sometimes even in everyday life, all conversions are really easier with metric so as soon as you want to manipulate physical amounts it becomes really easier and less error-prone.
Granted, it won't change the size of your oreos or make your car go faster, but in the end it would be easier for most and really handy for more scientific people.

The big issue here is changing people's minds. The UK succeeded switching to the metric system, so I guess Americans could do it as well. But I think that people in the US are fond of the imperial system because it is now one of the nation's symbols. So it likely won't change for a while.

I don't see how someone with a scientific mind could say that the metric system is not better. Yes a lot of people are not used to it, but from a scientific standpoint it's really better.

Re:Still can't handle proper units? (1, Insightful)

hedwards (940851) | about a year ago | (#44645015)

I can say that because nobody does those conversions with any frequency in every day living. If you're even claiming that, it means that you aren't paying attention.

I lived under the metric system for an entire year and not one time did it make anything easier for me. Not even a single conversion during that entire period was made more convenient by using SI units. And many things were less convenient because of the base 10 system they use. The most common conversions like distance into time are equally taxing regardless of whether you're using KMPH and KM or MPH and Miles. In either case you just divide the distance by the speed and you wind up with the same unit.

Weather was annoying because most of the year fluctuated within a 10 degree Celsius window giving less meaningful numbers than I would have had with Fahrenheit. And what's more, because the scale was designed with science in mind, the numbers themselves are far less logical for humans than with Fahrenheit.

In other words, despite all the propaganda out there, the metric system is of no additional value for every day living over Imperial measures and it makes certain things less convenient as the real magic of the metric system is the specially chosen units that make science easier, but have absolutely no connection with everyday living. I found most meat and produce to be sold by the half kilo, because that's a more convenient size to buy things in and coincidentally that's just a little bit more than a pound.

Re:Still can't handle proper units? (1)

tyrione (134248) | about a year ago | (#44646899)

Clearly you are not a Mechanical/Electrical or Chemical Engineer.

Re:Still can't handle proper units? (1)

SomeKDEUser (1243392) | about a year ago | (#44647267)

I do conversions all the time: I cook. I look up recipes. And US/Canadian recipes are written with deeply moronic idea that quantities of matter are easily measured by volume.

So I have this table of how much grams is a bloody cup of strawberries (and I don't know the kind of mental confusion which may lead anyone to think this makes the remotest amount of sense). Because if you want to be somewhat precise, there is only one single appropriate tool in a kitchen, and it is the scale.

Likewise, it is easier to mix liquids in ml (grams if it is water) and solids in precise amounts by weighing. And most importantly, this allows you to scale the recipes easily by the amount of the main ingredient.

As for the Fahrenheit thing, all I can say is that it is a truly moronic scale. From the freezing point of saturated brine to the body temperature of a human with a slight fever. Obviously this makes sense -- not. Feet, inches, miles, pounds, you know what? its some arbitrary choice. Fahrenheit is just dumb.

But whatever, these conversations usually boil done to this bizarre fact: Europeans like decimal notation, and Americans like fractions. And for sure, if you like fractions, you probably think conversions are not too useful. I can also tell you are American by the fact that you think "KMPH" is not disturbing as a notation: even in science, I find that Americans can think of acronyms as single entities, e.g they read ABC/DEF as "ABC"/"DEF", whereas Europeans will introduce symbols such as A_{foo}/B_{bar}.

As far as I can tell, this is the deep root of why notations/units are such. But the fact remains that measuring quantities of matter in volume is wrong :)

Re:Still can't handle proper units? (1)

Agent0013 (828350) | about a year ago | (#44645475)

Same thing for imperial units, it contributes absolutely nothing in daily living.

Yeah, it's just so easy to get 1/3rd of a meter. What is that then, 33.333333333333333333333333333333333333333333333333... cm? The number 12 divides evenly by many more amounts than 10 does. And 1/4th also, 25.25 as opposed to an even number of inches. This is the reason 12 and 60 are used in certain measures like feet, time, and degrees.

Re:Still can't handle proper units? (2)

jeremyp (130771) | about a year ago | (#44644039)

The whole point of using Imperial units is that we don't want to throw out trillions of dollars worth of infrastructure to make the Europeans happy. Seriously, spend a year in the US with our measures and spend a year somewhere that uses metric measures; metric isn't any easier for any thing you're likely to be doing on a day to day basis. Unless of course you're a scientist or engineer.

(my bold)

This is a story about science and engineering.

Re:Still can't handle proper units? (1)

hedwards (940851) | about a year ago | (#44644947)

Yes, but it's an article on an American site for a general audience. The mistake isn't that they used feet, the mistake is that they used metric for one and imperial for the other when they should have used feet in both instances.

The people doing the engineering aren't doing it based upon an article written after the devices were engineered and built.

Re:Still can't handle proper units? (0)

Anonymous Coward | about a year ago | (#44647061)

Yes, but it's an article on an American site for a general audience.

No, it's a science article on an American nerd site for an international audience. There is no such thing as a country-specific site on the internet, as I found out fifteen years ago with my Quake site; I had more visitors from Germany than from the US.

If the two telescopes were built using different measures (which I doubt, I should google but wtf), then the conversion should be to SI and not imperial. It isn't like all our soft drink bottles and engine sizes aren't measured in litres these days. Anybody at slashdot should be able to convert between the two easily, or question themselves as to whether they really belong here.

Re:Still can't handle proper units? (1)

SomeKDEUser (1243392) | about a year ago | (#44647287)

NASA uses metric. ESO uses metric. The value in feet is a translation the precision of which you do not know.

Re:Still can't handle proper units? (1)

WalksOnDirt (704461) | about a year ago | (#44646991)

I find cooking slightly easier in metric. It still takes me a moment to remember how many teaspoons are in an eight of a cup, for instance.

Re:Still can't handle proper units? (0)

Anonymous Coward | about a year ago | (#44642251)

And a dime from 100 miles away.

A dime, er, let me look that up. Oh, a small, nearly worthless U.S. coin, surpassed in worthlessness only by the Nickel and the Cent.

Re:Still can't handle proper units? (1)

Bengie (1121981) | about a year ago | (#44642849)

There are units for analogies?

Re:Still can't handle proper units? (2)

JWW (79176) | about a year ago | (#44643139)

Yes, the units for analogies are human hair, grain of sand, breadbox, car, football field, and internet.

Re:Still can't handle proper units? (1)

oodaloop (1229816) | about a year ago | (#44643711)

You forgot African bull elephant, VW Beetle, Library on Congress, telephone book, and golf ball.

Re:Still can't handle proper units? (3, Funny)

Thud457 (234763) | about a year ago | (#44644019)

actually, you're using the old, pre-normalization units. I has been scientifically proven that all units are convertible to Libraries of Congress.

1 Library of Congress = 25 Petabytes (data)
1 Library of Congress = 65,000,000 kilograms (mass)
1 Library of Congress = 30,000,000 m^3 (volume)
1 Library of Congress = 9,000,000 m of shelves (length)
1 Library of Congress = 53,700,000,000 BTU when burnt (energy)
1 Library of Congress = 11e10 seconds to read (time)
1 Library of Congress = 1,137 employees.
...

Re:Still can't handle proper units? (0)

Anonymous Coward | about a year ago | (#44642727)

Right in the summary we have a comparison between the 6.5 m Magellan telescope and the 8 ft Hubble.

I thought the more interesting units was "the equivalent of a dime viewed from more than a hundred miles away"... hundred miles to space... if you could do this trick pointed the other way, then you'd have a spy satellite that can resolve a dime.

Re:Still can't handle proper units? (1)

NatasRevol (731260) | about a year ago | (#44643191)

LOL at 'could'.

Re:Still can't handle proper units? (0)

Anonymous Coward | about a year ago | (#44644877)

How many six+ meter spy satellites are there? More typical 2-3 m ones are stuck at a ground resolution of about 10-20 cm assuming there was no atmosphere.

Re:Still can't handle proper units? (1)

dywolf (2673597) | about a year ago | (#44643773)

because taking the 0.09 seconds of mental math it takes to convert 6.5 into "~20ft" (or vice versa if so inclined) is too hard.

Re:Still can't handle proper units? (1)

dywolf (2673597) | about a year ago | (#44643789)

or even, hey, the summary also says the magellen is "21 feet" in direct comparison to the Hubble's 8. so the entire point of the thread is somewhat inflated to start with.

Awesome (0)

Anonymous Coward | about a year ago | (#44641977)

Just another reason we need space less and less. We can explore this vast and empty vacuum just fine from right here.

Re:Awesome (1)

instagib (879544) | about a year ago | (#44642033)

Despite this, I'd still like to see the images of a 30m lunar orbit space telescope.

Re:Awesome (0)

Anonymous Coward | about a year ago | (#44642087)

I'd like to see the output from that telescope with adaptive optics. We'd be able to count the hairs on an alien's ass!

Re:Awesome (2)

AlecC (512609) | about a year ago | (#44642311)

It wouldn't need adaptive optics. Those correct for atmospheric aberration, and the moon doesn't have any atmosphere.

However, I don't see the point of lunar rather than orbiting. Lunar has gravity, which must be compensated for in pointing the telescope, and half the sky is invisible at any instant. Orbiting has full access to the whole sky, and no pesky stray forces on the mirror.

Re:Awesome (3, Informative)

SecurityTheatre (2427858) | about a year ago | (#44642547)

All of these things are why the James Webb is going to go to the Lagrange point, rather than orbit.

Orbit is a dumb place to be for a telescope. :-)

Re:Awesome (1)

AlecC (512609) | about a year ago | (#44642643)

I thought the reason for the JWT to be at the Lagrange point was shielding from the sun. With supercooled IR sensors, the less sunlight the better. The life of the JWT is determined by how long its coolant lasts, And the Earth makes a good sunshield. The same is not true for an optical telescope - though any darkness is good, and coolness probably helps. But there is not the same driving need for an optical telescope to be kept cold as there is for an IR one.

Re:Awesome (0)

Anonymous Coward | about a year ago | (#44646797)

An object at a Lagrangian point *is* in orbit.

Re:Awesome (0)

Anonymous Coward | about a year ago | (#44642701)

Far side lunar telescope + radio telescope...

30m telescope in any orbit would be awesome, along with a very high focal length.

Although I would like to go bigger. Put every one in astronomy around the world towards the task of building a 100m telescope on the Moon. Lunar station on the side facing Earth, and fiber optic cable to the far side with a huge dish and a reflector in orbit above the surface.

Re:Awesome (1)

Waffle Iron (339739) | about a year ago | (#44642317)

Just another reason we need space less and less. We can explore this vast and empty vacuum just fine from right here.

But without space, we wouldn't be able to enjoy heroic stories about the maintenence staff using up an eight hour spacewalk to MacGyver open an access panel on the telescope. What fun is that?

Oh, wow. What you learn when you RTFA... (4, Interesting)

philovivero (321158) | about a year ago | (#44642225)

As to the above drama about mixing measuring units, the article says:

These images are also at least twice as sharp as what the Hubble Space Telescope (HST) can make because the 6.5m Magellan telescope is much larger than the 2.4m HST.

So there you go. Both measurements in Imperial European Units.

But then I read on, and was pretty stoked to see them discovering things like this.

MagAO was then used to map out all the positions of the brightest nearby Orion Trapezium cluster stars and was able to detect very small motions compared to older LBT data, a result of the stars slowly revolving around each other. Indeed, a small group of stars called Theta 1 Ori B1-B4 was proved to be likely a bound “mini-cluster” of stars that will likely eject the lowest mass star in the near future (see figure 4). This result has just been published in the Astrophysical Journal.

Nice! I'd love to see a time-lapse video over the course of the next million years watching this black sheep star get flung out of its little flock.

Re:Oh, wow. What you learn when you RTFA... (1)

ColdWetDog (752185) | about a year ago | (#44643375)

Nice! I'd love to see a time-lapse video over the course of the next million years watching this black sheep star get flung out of its little flock.

You'll probably have to sign up for this service [slashdot.org] first.

Re:Oh, wow. What you learn when you RTFA... (1)

jlfose (1063282) | about a year ago | (#44643929)

It is truly amazing that this level of resolution is available to earth bound telescopes. Granted that the location of this telescope is in a very remote desert, but at least it is accessible without a rocket when something needs to be swapped out. What I would be interested in though is to see a comparison of the images that the upgraded scope can provide for exposures longer than 24hours. Perhaps Hubble still has an edge here due to the imperfections of being able to cancel out all atmospheric turbulence over such a long period of time. Another related item ist that would be interesting is to apply some Big Data and HPC computing techniques on each microsecond of image data received by the sensor. It seems to me that sometimes the turbulence would be more random then normal making it harder to cancel out in the allotted fraction of a second. However those moments, if all individually recorded, could be evaluated such that the full frame, or subsection of the frame, could be subtracted from the final image. But perhaps they are doing that already, since the few astrophysicists that I've met tend to exploit even the most subtle of nuances that these photons can possibly reveal.

Re:Oh, wow. What you learn when you RTFA... (1)

Solandri (704621) | about a year ago | (#44646559)

Nice! I'd love to see a time-lapse video over the course of the next million years watching this black sheep star get flung out of its little flock.

Interesting bit of trivia - the first computational solution discovered for the 3-body problem [wikipedia.org] ended with one of the stars being flung out while the remaining two orbited each other as a binary system. It's since been found that most solutions end up this way [wolframscience.com] . Here's a video of one such system [youtube.com] ending with the middle-mass star being flung off.

Not entirely fair comparison (4, Interesting)

girlintraining (1395911) | about a year ago | (#44642247)

Hubble was sent into space with a major glitch in its primary mirror. While yes, we were able to give it, achem, corrective lenses for its near-sightedness, it was never able to perform to original specifications. This project, by comparison... doesn't have a defect in one of its most important components. So I don't know if this is an entirely fair comparison to make...

The fact is, they solve problems in two separate ways -- Hubble is a direct observation. There's no distortion, the light is the original and it's not smeared by atmospheric effect. Adaptive optics are amazing, but they're still additive in nature; You can photoshop, cut, and paste, but it'll never be quite as accurate as direct observation can be. That said, quite a lot can be done with it, and its a welcome addition especially in the age of limited scientific budgets for astronomy! I guess all I'm trying to say is... it's supplimentary, it is not a replacement for the kind of work Hubble did. We still need a replacement Hubble (obviously... with updated tech) for some observations.

Re:Not entirely fair comparison (3, Informative)

timeOday (582209) | about a year ago | (#44642801)

it was never able to perform to original specifications.

I thought the 2008 upgrade made it better than originally designed [newscientist.com] ?

With its new instruments, Hubble will be 90 times as powerful as it was supposed to be when first launched - it will be like having 90 of the original Hubble Space Telescopes, astronomers say. The improvement comes from a combination of increased sensitivity and wider fields of view, allowing Hubble to see 900 galaxies where its original instruments would have revealed only 10. HST will be about 60% more powerful than it was right after the third servicing mission, before ACS and STIS failed.

Re:Not entirely fair comparison (1)

hedwards (940851) | about a year ago | (#44643113)

From the looks of the article, it's 90x the repaired hubble's capabilities, which is probably 1/200th of what the Hubble would be able to do had it been launched with modern sensors today. The Hubble itself had 8 0.64MP CCDs to work with. Which at the time was quite good, but even if they used the CCD or CMOS from a low end dSLR, they could probably easily get 20x the pixels.

Re:Not entirely fair comparison (1)

Anonymous Coward | about a year ago | (#44646191)

the hubble telescope is diffraction limited to ~ 0.043 arcseconds (for optical wavelengths, 500 nm):
http://www.spacetelescope.org/about/faq/
this also states that it is slightly reduced by current camera resolution but post processing can pretty much remove that limit.

the main article says that the ground based telescope can now achieve ~0.02 arcseconds

Re:Not entirely fair comparison (0)

Anonymous Coward | about a year ago | (#44645347)

You must be new here. We have a tradition on Slashdot science articles where girlintraining post something that is wrong on multiple accounts, if not completely wrong in every regard, but we mod her up because it is tradition, or something.

Re:Not entirely fair comparison (1)

Nemyst (1383049) | about a year ago | (#44642969)

A replacement Hubble would be really hard because it's not really about tech, it's about mirror size. Have fun designing a larger mirror which can still be launched by rockets into space without a ridiculously prohibitive price tag, all with NASA's funding being cut down dramatically.

Re:Not entirely fair comparison (1)

hedwards (940851) | about a year ago | (#44643145)

Sort of, the original sensors on the Hubble had very little resolution to them. With modern pixel density you could get much larger photos that could be enlarged to a greater extent. Mirror size does play a role, but when you're talking about replacing the 0.64MP sensors with 12MP sensors, you can pull in a lot more detail with any given size of mirror.

Re:Not entirely fair comparison (0)

Anonymous Coward | about a year ago | (#44645097)

Those sensors were replaced, and the later system had two options: a wide field camera with 16 MP, and a high resolution system with about 1 MP. Adding smaller pixels beyond the resolution limit of the optics would be pointless, and would not increase the detail. It could allow you to take wider field images at maximum resolving power assuming there was room for the wider optics, but that wasn't what would be most desired at that point.

Re:Not entirely fair comparison (1)

azadrozny (576352) | about a year ago | (#44644055)

As I recall, the mirror size for Hubble was limited so that it could fit into the Space Shuttle payload bay. Since then, newer rockets have been developed that can lift heavier and bulkier objects into space.

Re:Not entirely fair comparison (1)

router (28432) | about a year ago | (#44646243)

Hubble size was limited because the Prime Contractor (Lockheed) already had some engineering and hardware to support the 2.4m size. They had developed it for another project looking down, not up.
http://en.wikipedia.org/wiki/KH-11_Kennan#Design [wikipedia.org]

andy

Re:Not entirely fair comparison (1)

Russ1642 (1087959) | about a year ago | (#44645517)

I'll bet we could polish it to the right spec this time around.

Re:Not entirely fair comparison (1)

Dahlgil (631022) | about a year ago | (#44643599)

I don't consider adaptive optics "additive" or "artificial". Adaptive optics, as I understand them, do not add new light but correct existing light like a sophisticated focuser. To me, the non-corrected image distorted by the atmosphere is more artificial than the corrected image, in which the atmospheric distortion has been subtracted out . Just as the repair work on the Hubble (or the optics on your glasses) did not "create" new or artificial light, neither does adaptive optics. One of the ways this can be proved is that in a post-processed image, you can only extract or enhance what is there. In this case, we are seeing detail that no post processing of the light could have visually revealed. This is not additive or artificial detail, it is real detail.

Re:Not entirely fair comparison (1)

DerekLyons (302214) | about a year ago | (#44644551)

Keep in mind that Hubble's mission is far more than just pictures... (though they get all the attention). Hubble is also a spectrographic instrument - and it can "see" wavelengths that do not penetrate the atmosphere.

There's more to astronomy than just who can create the sharpest and prettiest pictures.

Hubble resolution, at a price (5, Informative)

simonbp (412489) | about a year ago | (#44642267)

What they rarely mention in these sorts of press releases (everyone with AO system has a "better than Hubble" press release) is that the cost of getting to that resolution is losing most of the light along the way. It's not hard to beat HST with perfect atmospheric correction, as Hubble is only a 2.4 m aperture, and nearly every AO system is on a larger telescope. It's just that the correction is achieved by sufficient optical contortions that only a small fraction of the original light actually makes it to the detector.

My personal experience is that even the largest and most sensitive AO system in the world (NIRC II on Keck II with laser guide star) still really struggles make an observation in 20 minutes that Hubble can do in 5 minutes. If anyone were to launch a >3 m aperture visual-band space telescope (NOT JWST, that's IR), it would blow all these AO systems out of the water.

Re:Hubble resolution, at a price (2)

wonkey_monkey (2592601) | about a year ago | (#44642339)

It's just that the correction is achieved by sufficient optical contortions that only a small fraction of the original light actually makes it to the detector.

Got any numbers on that "small fraction"? Is most of it lost through the atmosphere, or inside the optics?

Re:Hubble resolution, at a price (2)

Arkh89 (2870391) | about a year ago | (#44642807)

Surface times Integration time...
Keck : 10m^2 and 30 minutes (yes, no need to count the pi/4 ratio as we will make a ratio out of it)
Hubble : 2.4m^2 and 5 minutes.
Ratio : approx. 1%

What about the spectral range between the two?

Re:Hubble resolution, at a price (1)

wonkey_monkey (2592601) | about a year ago | (#44643383)

I don't get it...

Are you assuming Keck and Hubble both collected the same number of photons in that time? If so, why? And where did those numbers come from?

Re:Hubble resolution, at a price (1)

Arkh89 (2870391) | about a year ago | (#44644003)

Yes, because photons are energy and all you care about is receiving most of it (actually transform it into a digital signal).
The assumptions made are extremely light too (and it should be 20 minutes of integration time leading to a 1.44% ratio). I used the number of the original message.
- Same absorption from entrance aperture to the sensor.
- Same sensor sensitivity (photon efficiency).
- Same sensor Signal To Noise Ratio (SNR).
- Same spectral bandwidth.
- Same spectral response of the global instrument in the considered spectral range.
- and many more...

Re:Hubble resolution, at a price (1)

wonkey_monkey (2592601) | about a year ago | (#44645693)

OP's statement from personal experience that

[Keck] still really struggles make an observation in 20 minutes that Hubble can do in 5 minutes

doesn't really sound like a scientifically solid statement from which to be doing calculations. That you might lose 99% of the signal from atmospheric effects and the like (despite AO) doesn't sound too unreasonable, but losing a large percentage of the light was what I was really questioning.

Are you assuming Keck and Hubble both collected the same number of photons in that time?

Yes, because photons are energy and all you care about is receiving most of it (actually transform it into a digital signal).

I still don't get why you'd assume Keck is only detecting the same number of photons in 30 (or 20) minutes as Hubble does in 5.

Re:Hubble resolution, at a price (0)

Anonymous Coward | about a year ago | (#44644341)

The small ratio he gave you is actually 1/x of the small fraction you asked to justify. 100 is not a small fraction, so you should simply confront him about that instead of asking some lame questions.

Re:Hubble resolution, at a price (1)

wonkey_monkey (2592601) | about a year ago | (#44645589)

What are you blathering on about?

Re:Hubble resolution, at a price (0)

Anonymous Coward | about a year ago | (#44645101)

I'm not sure where you get your exposure numbers from, considering both telescopes could chose a wide range of exposures as the situation required. Plenty of other sources, e.g. [lcas-astronomy.org] , describe that the mirror area is the main factor in light gathering (although it is easier to update sensors on ground telescopes as they improve, but there is diminishing returns there...).

Re:Hubble resolution, at a price (3, Informative)

simonbp (412489) | about a year ago | (#44643435)

Inside the optics. For optical/near-IR astronomy (i.e. roughly in the wavelengths that your eyes can see), atmospheric opacity only comes into play if there are clouds. You always want to look at objects higher in the sky (meaning through less atmosphere), but that's more because they have less distortion.

Inside the telescope, you lose some light every time you have a reflective surface. A simple telescope might have three reflective surfaces at 0.9 reflectivity, and so no more 3/4 of the original light reaches the detector. A complex AO system typically has closer to ten mirrors, so no more than a third of the original light will reach the detector. And that's before you account for all the other losses, like scattered light and the parts of the distortion that deformable mirror in the AO system can't correct for. So at worst case, it might be only 10% of the original light making it to the detector.

AO systems are great, especially for bright targets, but it always makes me cringe when people claim they are "better than Hubble". Space telescopes exist for reason...

Re:Hubble resolution, at a price (1)

Arkh89 (2870391) | about a year ago | (#44644069)

I doubt that they use mirrors with a reflectivity of only 90%. This might be true on large surfaces (meters+), with dust on it, but on smaller surfaces it gets more toward 99%.
For instance, simple Al2O3 coating has a reflectivity over 95%. And this is a basic coating, TiO2 can achieve 99%+.

Re:Hubble resolution, at a price (2)

Shag (3737) | about a year ago | (#44647115)

Reflectivity is also going to be affected by what wavelength they're observing at. Typically, AO is used for near-IR observations. Although I forget the exact figures, I know Gemini North uses silver to coat its primary now because it only absorbs something like 1/4 as much NIR as aluminum did. /Former aircraft spotter for the AO lasers at GN and Keck

Re:Hubble resolution, at a price (0)

Anonymous Coward | about a year ago | (#44644965)

Why would their adaptive optics be any different than other systems, which typically have only one more surface in a AO system: a splitter of some sort to sample the light coming in? The adaptive mirror is one of the mirrors that would have been there anyways, and the rest of the image path would be the same.

Re:Hubble resolution, at a price (1)

tyrione (134248) | about a year ago | (#44646941)

One would expect the denser the atmospheric composition of gases and thus the stronger the electromagnetic field the greater the distortion, cloud cumulation aside.

Re:Hubble resolution, at a price (1)

bill_mcgonigle (4333) | about a year ago | (#44642809)

still really struggles make an observation in 20 minutes that Hubble can do in 5 minutes.

Presumably this is a function of area? Does that mean double-diameter ground-based AO telescope will be as good as Hubble? How do the costs compare? (I realize doubling the area isn't a trivial undertaking).

As I understood it, the next 'frontier' in space telescopes was going to be a constellation parked out at a LaGrange point, not just a bigger Hubble since AO has made that type of telescope not worth doing. Somebody please inform.

Re:Hubble resolution, at a price (2)

Kjella (173770) | about a year ago | (#44642953)

My personal experience is that even the largest and most sensitive AO system in the world (NIRC II on Keck II with laser guide star) still really struggles make an observation in 20 minutes that Hubble can do in 5 minutes. If anyone were to launch a >3 m aperture visual-band space telescope (NOT JWST, that's IR), it would blow all these AO systems out of the water.

Yes, but "Hubble resolution, at a price" makes it sound like Hubble was the expensive one.

From its original total cost estimate of about US$400 million, the telescope had by now cost over $2.5 billion to construct. Hubble's cumulative costs up to this day are estimated to be several times higher still, roughly US$10 billion as of 2010.

Compared to that, the Magellan telescopes [noao.edu]

Total annual costs $10,437,639

That figure is including amortization of the $73 million dollar ($3,665,250*20) investment so $200 million total over 20 years. This means you can get 50 AOs for the cost of one Hubble, now which one comes "at a price" again?

Re:Hubble resolution, at a price (3, Informative)

dywolf (2673597) | about a year ago | (#44643839)

pretty sure the "price" he's referring to isn't monetary.

Reading comprehension. (1)

DerekLyons (302214) | about a year ago | (#44644607)

Did you actually read his comment? Or just reply to the subject line?

Not to mention, only the ignorant think that "price" is only reckoned in dollars.

Re:Hubble resolution, at a price (1)

hedwards (940851) | about a year ago | (#44643185)

Not really, you're ignoring changes in technology. These days it's relatively easy to create a sensor where nearly 100% of the light falling on the chip will hit one of your photosites. A typical dSLR sensor will have magnifiers that cover effectively 100% of the area.

I doubt that the original Hubble was as efficient with the light hitting the sensor as a modern dSLR sensor is. Sure, you do lose some photons in the process, but damn near all of them will hit one of the focusing lenses and be directed into a photosite.

Unit fail (1)

wonkey_monkey (2592601) | about a year ago | (#44642305)

the Magellan II 6.5-meter telescope... [w]ith its 21-foot diameter mirror

Oh, for... one or the other, c'mon.

Modern Ferraris and 57 Chevies: (1)

Hartree (191324) | about a year ago | (#44644305)

You do realize there's just a bit of time lag here?

The Hubble was supposed to launch in 1983 (delays in building and the Challenger disaster held it up till 1990). So, it's at best 30 year old tech (and actually since it was space rated, a good bit older than that).

The Magellan II is brand spiffy new and can take advantage of many things that Hubble can't since it needs to be at least somewhat rad hard.

Granted that Hubble has been upgraded, but I don't think it's a fair comparison.

If we ever get the James Webb Telescope launched, that might be a fairer comparison.

8 Meter Space Telescope (0)

Anonymous Coward | about a year ago | (#44644455)

Astronomers were proposing [space.com] to use Ares V to launch an 8 meter reflector into space. 1.5 meters larger than Megellan; 35% more collecting area and far above the atmosphere. That mirror would have been able to detect biosignatures [wikipedia.org] on extrasolar planets.

Then Obama [wikipedia.org] cancelled it, so you probably won't live to see such a thing.

Re:8 Meter Space Telescope (0)

Anonymous Coward | about a year ago | (#44645249)

Except the replacement for the Ares, the Space Launch System, includes a version that would be able to launch the same 8 meter reflector.

moon lander still too small / far away (0)

Anonymous Coward | about a year ago | (#44644733)

according to this 5 year old article
http://blogs.discovermagazine.com/badastronomy/2008/08/12/moon-hoax-why-not-use-telescopes-to-look-at-the-landers/#.UhZC2_GB1xk
0.02 arcseconds is still an order of magnitude away from seeing the apollo lander (assuming 4 meters across, but 400,000,000 meters away = .002ac)
getting there though,

Resolution vs. field of view (1)

DonaldGary (2451128) | about a year ago | (#44645085)

I don't know what the current state of the art is, but once upon a time it was only possible to correct a for atmospheric variations over a very narrow field of view. You will notice that the first light images are of binary stars and not of whole nebulae or galaxies. I don't think this is an accident.

Finally! (2)

GeekZilla (398185) | about a year ago | (#44645745)

We can finally quiet the "moon landing was a hoax" nutjobs. With the ability to make long-exposure images that resolve objects just 0.02 arcseconds across — the equivalent of a dime viewed from more than a hundred miles away", we can actually take pictures of all the junk we left behind as proof that we were actually there.

Cool (0)

Anonymous Coward | about a year ago | (#44646561)

That only took 23 years (yes, I know, different tech). Still... Ne would kind of expect that 23 years later. 1/4 of a frickin millennium.

Fourier mirrors (0)

Anonymous Coward | about a year ago | (#44646733)

Screw mirrors and adaptive optics I want optical frequency antennas and a really fast computer.

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