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Super Telescopes

02/06/2008 10:01 AM

I thought this was an interesting article. Basically it talks about a number of large telescope projects going on around the world.

WASHINGTON (AP) -- A telescope arms race is taking shape around the world. Astronomers are drawing up plans for the biggest, most powerful instruments ever constructed, capable of peering far deeper into the universe -- and further back in time -- than ever before. The building boom, which is expected to play out over the next decade and cost billions of dollars, is being driven by technological advances that afford unprecedented clarity and magnification. Some scientists say it will be much like switching from regular TV to high-definition.

In fact, the super-sized telescopes will yield even finer pictures than the Hubble Space Telescope, which was put in orbit in 1990 and was long considered superior because its view was freed from the distorting effects of Earth's atmosphere. But now, land-based telescopes can correct for such distortion. Just the names of many of the proposed observatories suggest an arms race: the Giant Magellan Telescope, the Thirty Meter Telescope and the European Extremely Large Telescope, which was downsized from the OverWhelmingly Large Telescope. Add to those three big ground observatories a new super eye in the sky, NASA's James Webb Space Telescope, scheduled for launch in 2013.

With these proposed giant telescopes, astronomers hope to get the first pictures of planets outside our solar system, watch stars and planets being born, and catch a glimpse of what was happening near the birth of the universe. "We know almost nothing about the universe in its early stages," said Carnegie Observatories director Wendy Freedman, who chairs the board that is building the Giant Magellan Telescope. "The GMT is going to see in action the first stars, the first galaxies, the first supernovae, the first black holes to form." When scientists look at a faraway celestial object, they are seeing it as it existed millions and millions of years ago, because it takes so long for light from the object to reach Earth.

Current telescopes are able to look back only about 1 billion years in time. But the new telescopes will be so powerful that they should be able to gaze back to a couple of hundred million years after the Big Bang, which scientists believe happened 13.7 billion years ago. That's where all the action is. "We hope to answer these questions: Are we alone in the universe? What is the nature of dark matter and dark energy in the universe?" said astronomer Henri Boffin, outreach scientist for the European Southern Observatory.

An 80-foot mirror

Two new technologies enable this extraordinary quest -- one reliant on modern lasers and computing power and the other inspired by ancient Greek and Roman tilework. The first is adaptive optics. It allows telescopes on the ground to get rid of the distortion caused when looking through Earth's thick atmosphere into space. Adaptive optics relies on a laser to create an artificial star, or a constellation of fake stars, in the sky. Astronomers then examine the fake stars and use computers to calculate how much atmospheric distortion there is at any given time. Then they adjust the mirrors to compensate like a pair of eyeglasses. This adjustment happens automatically hundreds of times per second.

Adaptive optics worked first for smaller telescopes. But getting it to work for big observatories was a problem. The first successful use in large telescopes was in 2003 at the twin-telescope Keck Observatory in Hawaii, an effort that took nine years. The second breakthrough involves technology that makes bigger mirrors possible. Instead of casting a giant mirror in one piece, which is difficult and limits size, astronomers now make smaller mirror segments and piece them together.

Keck scientist Jerry Nelson, now working on the Thirty Meter Telescope, pioneered this technique and said he got the idea from looking at how the Greeks and Romans tiled their baths. This technique is going from 36 segments in current telescopes to 492 segments with his new project. In astronomy, the bigger the mirror, the greater the amount of light that can be grabbed from the universe. For the past decade and a half, the Keck has had the largest Earth-bound telescopes, with mirrors nearly 33 feet in diameter.

However, three giant land observatories, proposed for construction within the decade, are going to dwarf those:

  • The Giant Magellan Telescope. A partnership of six U.S. universities, an Australian college, the Smithsonian Astrophysical Observatory and the Carnegie Institution of Washington will place the telescope in Las Campanas, Chile, around 2016. The plan is for an 80-foot mirror. The cost is around $500 million.
  • The Thirty Meter Telescope. The California Institute of Technology, the University of California and the Association of Canadian Universities for Research in Astronomy are aiming for a telescope with about a 98-foot mirror by 2018. No site has been chosen. The cost is about $780 million.
  • The European Extremely Large Telescope. A partnership of European countries called the European Southern Observatory already has telescopes in Chile and is aiming for a new one with a mirror of 138 feet, scaled back from initial plans of 328 feet. The Europeans are aiming for a 2018 completion, but have not chosen a specific location yet. The cost would be $1.17 billion.

Hubble's so 5-minutes ago

The managers of these projects are fairly confident they will get the money they need to complete their grand visions. However, some astronomers worry that there may not be enough private or government money for all of them, so they find themselves competing for funding, even as they cheer each other on. If completed, ESO's European Extremely Large Telescope would be the biggest of the new observatories and should be able to see 20 to 100 times more sharply than the current best land-based telescopes.

The Hubble, which set the standard for stunning astronomical pictures, will seem less amazing. "Oh, you ain't seen nothing yet," said 2006 Nobel Prize-winning physicist John Mather, senior project scientist for NASA's James Webb Space Telescope. The $4.5 billion Webb Telescope, designed to travel 900,000 miles beyond Earth's orbit, is not faced with the atmospheric distortion of ground telescopes. Still, it will use its own version of adaptive optics. Because of temperature fluctuations in the cold of space, the telescope will have to adjust the shape of its mirrors automatically. Webb's mirror, which is 21/2 times bigger than Hubble's, has 18 segments. While places like Arizona and Hawaii have been successful sites for high-quality space images, Chile is the focal point of the next-generation building boom. Both the Thirty Meter and European telescope are looking at several sites there although the Thirty Meter team is also considering Baja Mexico and Hawaii.

What's needed is the right combination of atmospheric conditions, weather, high altitude, prevailing winds and dark skies. But there is more in the works than just the super-sized scopes. Smaller, more specialized telescopes are in various stages of design and construction. The $400 million Large Synoptic Survey Telescope to be built in Chile by 2014 would survey the sky, constantly shooting a movie of 20 billion objects in the cosmos and spotting targets for bigger telescopes. A planned project in Hawaii would be on the lookout for "killer asteroids." And in Chile, dozens of high-precision antennas are being erected for a huge radio astronomy observatory, called ALMA, that would look into the universe in a different way. It is the biggest observatories in the works, however, that will provide the dramatic change in astronomical pictures. The pictures to come, Nelson said of the Thirty Meter project, will "knock your socks off, faint stuff that Hubble can't see."

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Guru

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#1

Re: Super Telescopes

02/06/2008 2:28 PM

I have just been to a reading from Dr Craig McKay from Cambridge Institute of Astronomy, and he talked about his new invention that "takes the twinkle out of stars".

It works completely on software calculations and has remarkable results. His tests so far have shown that even older 200 inch (5 meter) telescopes are capable of taking pictures that are about twice as sharper than the Hubble pics. This is absolutely stunning and has to be seen to believe it.

His next step is to optimise it so it also works well on larger sizes as this was a bit of a limiting factor till now. I hope he will manage as it will open up a new chapter in amateur astronomy as well (again).

His system is called Lucky Imaging and his website is here.

Have fun.

p.s. Dr Craig McKay is the founder of Astro Cam. The company that pioneered ccd imaging in the early years. His company was bought up by a life science company from the region that wanted to use this technology for medical imaging. I suppose this shows where Dr McKay gets the background from.

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#2

Re: Super Telescopes

02/06/2008 2:34 PM

Hmmmmmm fascinating!!

And I thought the Hubble was good, back in the 60s it was the Mount Wilson that had the largest mirror (can't remember the size - perhaps 150"?) and now they're talking of maybe 100 metres!!?

John.

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#3
In reply to #2

Re: Super Telescopes

02/07/2008 4:40 AM

Hi,

Mount Wilson was upgraded many years ago with an adaptive optics system.

And now producing many good results despite being plagued by the stray light from nearby streetlights of a supercity.

RHABE

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#4

Re: Super Telescopes

02/07/2008 4:53 PM

What the story tells me in a compelling fashion, is that the power of human ingenuity. Couple that with (widely unlimited) means, and most problems appear quite solvable.

To the story of telescopes of any kind: from many stories it appears to me, that the light (or IR or radio) gathering capability of individual dishes is plenty good. What is missing is angular resolution, that is dependent on the size, or the number of dishes spaced far apart, to produce signals for interferometer. In radio range that is a reality, by combining signals from dishes from the opposite side of the Earth, or the dish farm in New Mexico. Next step is to send dishes of barely adequate size up in space. Their distance (the baseline) can be 10-100 times that of the earth based ones, hence proportionally higher resolution. THAT cannot be reached on earth. Light gathering by sheer size can.

One major advantage of space deployment is, that sagging due gravity is not an issue. God knows, there are enough others, to make the deployment anything but trivial.

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Guru

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#5

Re: Super Telescopes

02/13/2008 1:41 PM

Hi guys,

I found out that this year (or next year depending on what view you take) it is the 400th birthday of the telescope.

Now that is some little gem I did not know before.

I also found this nice website full of information about the history of the telescope including where some of the names came from, lentils apparently.

Go here and enjoy.

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#6

Re: Super Homemade Telescopes

02/13/2008 2:40 PM

Lewis Smith

ST ALBANS An amateur astronomer took a webcam image of the space shuttle Atlantis docking with the International Space Station using a home-made telescope.

Martin Lewis, 46, used an 8in reflecting telescope in his garden in St Albans, Hertfordshire, to view the space station when it flew directly over Britain. To the naked eye the space station and shuttle appear as a bright light moving slowly across the night sky but with the telescope details such as the distinctive solar panels became easily recognisable. "I was really pleased as I've wanted to get this shot with the two spacecraft together for ages," Mr Lewis said.

Now that is what I call a super telescope!

Forget your super big enourmous monster, this guy shows us we can all do something exiting with only 8 inches.

Go on, you know you want to

My hat of to Mr Lewis, he is an inspiration.

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#7
In reply to #6

Re: Super Homemade Telescopes

02/13/2008 3:36 PM

I heartily concur, 8 inches is quite enough...

Especially as Mr Lewis is just down the road from me!!

John.

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#8
In reply to #7

Re: Super Homemade Telescopes

02/13/2008 4:30 PM

I know I did intend a pun somewhere down that line.....

I is however still a seriously big achievement in my mind and I know as I am trying all sorts with my telescope and cannot dream of getting anything like that for the moment.

Best I can do is hope as I have not even calibrated the drives on my telescope yet. This means that it is not moving smooth and does not track correctly, making long exposures impossible for now. I will probably do this in the summer after I have moved my garden pier so my new telescope cables can reach it out of my window.

First almost acceptable pics:


Not what I call very worthy results yet but it will come.

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#9
In reply to #8

Re: Super Homemade Telescopes

02/14/2008 8:52 AM

Hey they are great pictures, how did you take them? Was it with a film camera?

My telescope is fine at tracking objects with its motor drive but what amazes me about that first picture is that the tracking of a satellite needs some computer to keep the 'scope on target doesn't it??

John.

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#10
In reply to #9

Re: Super Homemade Telescopes

02/14/2008 3:05 PM

I took them with a budget ccd made by Meade through my ETX90nft. It is only small in pixel amount compared to some of the big guns out there but for what I want to , and able to do, it will suffice for quite a while. Still learning and what I have learned so far is that it will take at least another 10 years of learning before I realise the learning will never stop. There is no upper limit to what you can learn but I only know that because I have skipped a few paragraphs in my book and cheated.

Most telescopes with tracking can be split in a few groups.

1) manual, these are just 2 or 3 axis equatorial heads with manual control for one or more of the axis.

2) single axis motor driven. These are just as above but now with one motor on the RA axis with often a few speeds on it for tracking and positioning.

3) dual axis motor control. As above but now with fully motor driven for both positioning and tracking.

4) full blown computer control for dual motor drive.

Some of the last group can be split into 2 groups again which would be equatorial or fork mount.

As soon as you have computer control, often you have a library of stars in the "goto" function of the device which enables you to auto find your object after initialisation of the telescope. This library can have the option of "custom objects" to add to the data base. If you have that option you can simply find the tables for the object you want to follow on the internet and put them in your user data base for tracking.

This guy with his 8 inch reflector in his back garden did it all by hand however. He probably has an equatorial head with or without motors but that would not give you the option of following something that "moves against the grain" as satellites do. He states that once he found the satellite he hit the record button and kept the satellite in the view finder as good as he could.

Depending on how well he did that, he could then stack his pictures with an external optimising program such as registax4. Sounds simple but inherently difficult. He is obviously very good at it as the picture shows very large amounts of detail which is a tribute to his skills of both imaging and telescope building.

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