New telescope brings the power of Hubble down to Earth

From the University of Arizona

UA astronomers take sharpest photos ever of the night sky

MAGAO_telescope

The Magellan Telescope with MagAO’s Adaptive Secondary Mirror (ASM) is mounted at the top looking down some 30 feet onto the 21-foot diameter primary mirror, which is encased inside the blue mirror cell. Credit: Yuri Beletsky, Las Campanas Observatory

Using a new camera and a telescope mirror that vibrates a thousand times each second to counteract atmospheric flickering, astronomers have achieved image resolution capabilities that could see a baseball diamond on the moon

Astronomers at the University of Arizona, the Arcetri Observatory near Florence, Italy and the Carnegie Observatory have developed a new type of camera that allows scientists to take sharper images of the night sky than ever before.

The team has been developing this technology for more than 20 years at observatories in Arizona, most recently at the Large Binocular Telescope, or LBT, and has now deployed the latest version of these cameras in the high desert of Chile at the Magellan 6.5-meter telescope.

“It was very exciting to see this new camera make the night sky look sharper than has ever before been possible,” said UA astronomy professor Laird Close, the project’s principal scientist. “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. At that resolution, you could see a baseball diamond on the moon.”

The twofold improvement over past efforts rests on the fact that for the first time, a telescope with a large diameter primary mirror is being used for digital photography at its theoretical resolution limit in visible wavelengths – light that the human eye can see.

“As we move towards shorter wavelengths, image sharpness improves,” said Jared Males, a NASA Sagan Fellow at the UA’s department of astronomy. “Until now, large telescopes could make the theoretically sharpest photos only in infrared – or long wavelength – light, but our new camera can take photos that are twice as sharp in the visible light spectrum.”

Equipped with the newly developed MagAO adaptive optics system, the Magellan Telescope revealed details about the Orion nebula. The background image, taken with the Hubble Space Telescope, shows the Trapezium cluster of young stars (pink) still in the process of forming. The middle inset photo reveals the binary nature of the Theta Ori C star pair. The bottom insert shows a different binary young star pair shaped by the stellar wind from Theta 1 Ori C. Credit: Laird Close and Ya-Lin Wu; NASA, C.R. O’Dell and S.K. Wong

 

These images are also at least twice as sharp as what the Hubble Space Telescope can make, because 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.

To overcome atmospheric turbulence, which plagues earth-based telescopes by causing the image to blur, Close’s team developed a very powerful adaptive optics system that floats a thin (1/16th of an inch) curved glass mirror (2.8 feet across) on a magnetic field 30 feet above the telescope’s primary mirror.

This so-called Adaptive Secondary Mirror (ASM) can change its shape at 585 points on its surface 1,000 times each second, counteracting the blurring effects of the atmosphere.

“As a result, we can see the visible sky more clearly than ever before,” Close said. “It’s almost like having a telescope with a 21-foot mirror in space.”

The new adaptive optics system, called MagAO for “Magellan Adaptive Optics,” has already made some important scientific discoveries, published today in three scientific papers in the Astrophysical Journal. As the system was being tested and received what astronomers call “first light,” the team pointed it to a famous and well-studied massive star that gives the Great Orion Nebula (Object M42) most of its UV light. The Orion Nebula, located just below Orion’s Belt visible as smudge of light even with regular binoculars.

Considered young at about 1 million years old, this star, called Theta 1 Ori C, has been previously known to be in fact a binary star pair made up of two stars called C1 and C2. However, the separation between the two is so small – about the average distance between Earth and Uranus – that astronomers had never been able to resolve the famous pair in a direct telescope photo.

Once MagAO and its visible science camera called VisAO were pointed towards Theta Ori 1 C, the results were immediate.

“I have been imaging Theta 1 Ori C for more than 20 years and never could directly see that it was in fact two stars,” Close said. “But as soon as we turned on the MagAO system it was beautifully split into two stars.”

In another result, MagAO has shed light on another mystery: How do how planets form from disks of dust and gas affected by the strong ionizing light called stellar wind coming from a massive star like Theta 1 Ori C, which has about 44 times the mass of the sun?

The team used MagAO and VisAO to look for red light from ionized hydrogen gas to trace out how the strong UV radiation and stellar wind from Theta 1 Ori C affects the disks around its neighboring stars.

The power of visible light adaptive optics: On the left is a “normal” photo of the theta 1 Ori C binary star in red light. The middle image shows the same object, but with MagAO’s adaptive optics system turned on. Eliminating the atmospheric blurring, the resulting photo becomes about 17 times sharper, turning a blob into a crisp image of a binary star pair. These are the highest resolution photos taken by a telescope. Credit: Laird Close/UA

“Close to Theta 1 Ori C, there are two very young stars surrounded by disks of gas and dust,” said Ya-Lin Wu, a graduate student and lead author on one of the publications. “Theta 1 Ori C pummels those disks with stellar wind and UV light. It looks like they are being bent backwards by a strong wind.”

MagAO’s photo revealed that the two stars and their protoplanetary disks are heavily distorted into teardrop shapes as the strong UV light and wind create shock fronts and drag gas downwind of the pair.

The distribution of gas and dust in young planetary systems is another unsolved problem in planet formation. The team used VisAO’s simultaneous/spectral differential imager, or SDI, to estimate the mass of another intriguing object in the Orion Nebula: one of a few stars in Orion sporting a rare “silhouette disk.” The SDI camera allowed the light from the star to be removed at a very high level—offering, for the first time, a clear look at the inner regions of the silhouette.

“The disk lies in front of the bright Orion nebula, so we see the dark shadow cast as the dust in the disk absorbs background light from the nebula,” said Kate Follette, a graduate student and lead author of one of the three papers published in the Astrophysical Journal. “Picture a moth flying across a bright movie screen: Its body will appear opaque, while the wings will be partially transparent. Our SDI instrument allows us to peer into the silhouette and trace how much dust is at each location in the disk based on how transparent or opaque it is.”

“We were surprised to find that the amount of attenuated light from the nebula never reached an opaque point,” she said. “It seems as though the outer parts of this disk have less dust than we would have expected.”

“It is important to understand how dust is laid out in these objects because that dust and gas is what nature uses to build planets,” Close explained. “Our new imaging capabilities revealed there is very little dust and gas in the outer part of the disk.”

According to Close, the silhouette disk might have been close to the massive star Theta 1 Ori C at some point, which might have blown away its outer dust and gas.

“This tells us something about planet-forming disks in these dense, stellar nurseries,” Close said. “There appears to be a limit to the formation of massive planets very far away from their parent stars. One possible explanation might be the presence of a massive star like Theta 1 Ori C stripping away the outer gas and dust.”

###

The MagAO system was developed with support of the National Science Foundation MRI, TSIP and ATI grant programs. The Adaptive Secondary Mirror itself was produced by Microgate and ADS of Italy, with the UA’s Steward Observatory Mirror Lab. The MagAO pyramid wavefront sensor was developed at the Arcetri Observatory, Italy. The Magellan telescopes are operated by a partnership between the Carnegie institute, the UA Harvard University, MIT and the University of Michigan. The work of NASA Sagan Fellows Jared Males and Katie Morzinski was performed in part under contract with the California Institute of Technology and was funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. The work of Kate Follette was funded in part by the NSF Graduate Research Fellowship program.

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77 thoughts on “New telescope brings the power of Hubble down to Earth

  1. I have Cannon stabilizer binoculars that do the same thing. Great pair of binoculars. I wonder if stabilizers on binoculars and movie cameras came before or after this technology as applied to telescopes?

  2. As soon as NASA turned its equipment inwards for “mission earth” it stopped doing its job. Since when did anyone need a Space Agency to study the planet earth? Washington might be on a different planet, but the rest of us are still here on good old planet earth. The job of the Space Agency should be to explore space. Earth is not a candidate for that work, which is why NASA went so badly off the rails.

  3. There are many ground based devices that do this anyway, so nothing new other than recognising the fact. So they adjust for “Atmospheric Scintillation”? No kidding…

  4. Adam Gallon says:
    “Defund GISS by 90% & spend that on this sort of thing!”
    Why fund 10% of current GISS inanity? Drop it like it’s Pluto!

  5. ferdberple says:
    As soon as NASA turned its equipment inwards for “mission earth” it stopped doing its job. Since when did anyone need a Space Agency to study the planet earth? Washington might be on a different planet, but the rest of us are still here on good old planet earth. The job of the Space Agency should be to explore space. Earth is not a candidate for that work, which is why NASA went so badly off the rails.
    ==
    Yeah , we’ve all had enough of GISS climate propaganda but let’s stick to the facts.
    It’s NASA , not SA. Checkout what it stands for.
    Also satellites are “spacecraft” , so no contradiction there. They need rockets to get them up there, Seems like classic jobs for a space agency.
    NASA’s motto is not “to boldly go ….” you seem to be confusing things a little.
    Why Hansen’s little corner of NASA was allowed to go off the rails and remain that way for so long and why he was allowed to have income from outside sources is a question that needs answering.
    I should also point out that satellite data are a useful asset to those trying to objectively assess climate. That cuts both ways.
    There is a danger that as evidence mounts against AGW they may well defund satellites to prevent us having a record of it NOT warming.
    Be careful what you call for.

  6. Steve from Rockwood says:
    August 24, 2013 at 9:36 am
    If we can “see” further into space will the Universe get older?
    >>>>>
    No, we get younger! 🙂

  7. Does anyone how much degradation occurs from natural light pollution from airglow (http://en.wikipedia.org/wiki/Airglow). Does the new level of clarity allow us to take pictures that take 11 day equivalent exposures from earth or does the airglow make that impossible? It would really be fun if we could get this stuff into space.

  8. “At that resolution, you could see a baseball diamond on the moon.”
    Great, so they should turn it to look at the moon. Then we can see all the mysterious objects that they photoshopped out of all the other lunar surface photos we already have, before releasing them.
    That would probably be far more interesting than just being able to resolve a binary star. Pretty as it.

  9. Always impressive, but perspective is the tool of the illusionist.. We can never be sure just what we are seeing unless we can make observations from different angles.. Ive seen gravity defied with a ball rolling uphill or two structures that look identical, all false and due to perspective..
    Better than nothing and still very cool, but penning in the laws of the universe with your rear end nailed to the chair leaves room for major errors.

  10. Now we can find out for once and for all if the Apollo astronauts really did play baseball on Mars.

  11. “”””””…….Pamela Gray says:
    August 24, 2013 at 8:39 am
    I have Cannon stabilizer binoculars that do the same thing. Great pair of binoculars. I wonder if stabilizers on binoculars and movie cameras came before or after this technology as applied to telescopes?……..””””””””
    Sorry Pamela but your Canon binoculars do not do this.
    They do stabilize the image somewhat so that it compensates for your hand movement, but if you put your binoculars on a tripod, so they didn’t move, the image wouldn’t be any sharper; just not moving.
    This new gizmo, behaves as if the front lens of your binos, was broken up into a thousand different pieces, and each one could automatically move in and out to keep the light through it in focus. Of course you have to know whether each piece is in focus or not. That is, your binos have to know that, so they can automatically refocus, their piece of the puzzle.
    In principle, you could do the same thing with the rippled clear glass sliding door on your shower, so each facet could move separately, and then one could have a nice sharp look at that butterfly on your left shoulder.
    PS most top brand digital cameras, (Canon, Nikon etc all have optical image stabilization built into them or their lenses. None of them have adaptive optical image sharpening built into them.

  12. …you could do the same thing with the rippled clear glass sliding door on your shower, so each facet could move separately, and then one could have a nice sharp look at that butterfly on your left shoulder.

    Right shoulder. The butterfly on her left side is, uhm, “elsewhere” …. 8<)

  13. Greg says:
    August 24, 2013 at 9:55 am

    Great, so they should turn it to look at the moon. Then we can see all the mysterious objects that they photoshopped out of all the other lunar surface photos we already have, before releasing them.

    Greg,
    References please.

  14. Now we might have a good chance of seeing who or what is in the general neighborhood…
    Like an earth-like planet?

  15. Excellent, this is just the technology we need to help us in our search for the “missing heat”.

  16. Great post. Off topic a bit, but one that I will share with others. Keep these rare, but keep them coming….

  17. The mind boggles. Even if our universe is finite, in what does that reside? And beyond that? Embiggening.


  18. Pamela Gray says:
    August 24, 2013 at 8:39 am
    I have Cannon stabilizer binoculars that do the same thing. Great pair of binoculars. I wonder if stabilizers on binoculars and movie cameras came before or after this technology as applied to telescopes?

    Consumer cameras and binoculars have been around several years but not much longer than that. The origins of these image stabilizing systems date back to the 50s using what is referred to as tilt/tip. This is where a flat mirror is adjusted in its position to keep a star at the same point in the frame. The full ‘rubber mirror’ adaptive optics has only been possible for the last couple of decades. It requires very sensitive cameras and lots of processing power. It is also probably not used for anything but rather large telescopes. The original concepts were developed as part of the strategic defense initiative to correct laser wavefronts for taking out nuclear bomb delivery systems by reflecting powerful groundbased lasers off of special satellites. It was tested on space shuttle flights but I never heard of anything more being created. Most of what has been done has been in the infrared because visible light is harder to accomplish.

  19. nice of them to make an international report in american jargon. Had to look up what a baseball diamond was. It’s a big square. Maybe in the next improvement of telescope they can see a Pallone col bracciale width. And we all know what that means,.

  20. Quite a few of the large earth-based observatories now have adaptive optics in the form of a dynamically deformable secondary mirror to counter academic distortion. I had some involvement with the Hawaiian Keck Observatory’s implementation of AO more than 5 years ago. They sent me a picture of the first picture of Uranus’ rings taken from the earth’s surface when they first got it working.
    When combined with the very large primary mirrors made possible by controlling segmented sections in coordination, the new capabilities of earthbound telescopes have dramatically reduced the role of orbiting telescopes. They are primarily used now to monitor wavelengths to which the earth’s atmosphere is opaque, notably the far infrared. (Slayers take note – I have seen claims from prominent slayers that if the greenhouse effect were real, we couldn’t have [far] infrared telescopy … and we can’t, not from the earth’s surface!)

  21. Quick, tell Lew that we no longer believe the conspiracy that the moon landing was faked as we can see the baseball diamond they built up there.

  22. beng says:
    August 24, 2013 at 8:59 am
    Impressive. Astronomy is one of my passions. Can close binary stars have stable planetary systems?
    I second that comment….

  23. Trully amazing. I would be fascinated to know how mirror vibration is calibrated. Reference star?
    Given that it is a upgrade to the secondary mirror, every major optical telescope can now be upgraded with this system. This is fantastic news, except for astronomy students. Want time on the new hotness? You will now need hair to rival Rupunzel and a rack to rival May West or you’re not in the running sunshine.

  24. All AO systems need a reference – usually a point source like a star or the distant “star” in the upper atmosphere produced by a laser is used as the source of spherical wavefronts that become distorted in the passage through the atmosphere.
    BTW, the Canon system corrects the low order terms of tip/tilt induced by handheld shake. It does this with accelerometers to drive a variable wedge transmissive optic. The next step up in AO would include focus, then the low order aberration terms of coma, astigmatism, and spherical aberration. That takes about 36 actuators – usually describe by the Zernike orthogonal polynomials. After that are the higher order terms (Kolmogorov statistics described turbulence) and that just goes on a ways. At some point as turbulence deepens it’s not possible to unwrap the phase distortion without using more subtle tricks. I wonder what tricks the UA team might be using?
    There are other ways of producing the reference, and other methods of sharpening the image without a distant point reference (phase diversity) but these require even more computing power and have intrinsic photon limits (not enough photons!)
    I’m about to go off mountaineering, but when I get back I’ll be interested in seeing this new “record” in resolution.

  25. “At that resolution, you could see a baseball diamond on the moon.”
    If you build it, no one will come. Not even “They.”

  26. I can see the point of being able to find a dime from a hundred miles away, but why would anyone want to see a baseball diamond on the moon?

  27. “nice of them to make an international report in american jargon.’
    Americans don’t make international reports. They never think beyond the domestic, even when they are getting assistance from other countries.

  28. RoHa says:
    August 24, 2013 at 5:35 pm

    I can see the point of being able to find a dime from a hundred miles away, but why would anyone want to see a baseball diamond on the moon?

    You’ve never heard of the Fever Pitch Syndrome? Based on a great movie by the same name. /sarc

  29. beng says:
    August 24, 2013 at 8:59 am
    Impressive. Astronomy is one of my passions. Can close binary stars have stable planetary systems?

    I did a COMPUTER MODEL using only Newton’s gravity (I did not want to tackle Einstein’s equations) that showed several orbital sweet spots for a three body system with two Sol sized stars and an Earth sized planet. The closest stable point for such a planet turned out to be about twice the distance between the two stars outside of their orbits. For wider spaced stars, at about 4AU it was just possible to place the planet in a 1AU orbit around one of the two stars. There was more leeway as the stars were farther apart. NOTE: the model did not even attempt to explain how the planet and stars happened to arrive in those configurations. There have been some pretty neat accretion models run by NASA researchers that have actually started with a cloud and attempted to produce our solar system and other configurations using only Newton and some statistical techniques to improve computation efficiency. They have done a couple of binary systems for this, but I have lost my undergraduate paper in a hard drive crash so can’t find the references again. They were trying to identify markers that might be visible to astronomers to try to detect this type of system. I suffered total processor/algorithm envy reading those papers.
    It was a fun project. As my proto-Earths were burned up in one of the stars or flung into deep space numerous times in run after run. Some of the configurations would look promising for the first 10 million years or so then something would perturb an orbit and fling it off or crash it. Unfortunately system memory limitations would not let me run much longer then 10 million years though. I really need to dust off that code and see if today’s more powerful machines can give me more years. Also if things got too close together energy would bleed in my code and I never found the leak (I suspect it was a truncation error.) If I started the two stars closer together than 1 AU, they would drift out to 3AU after a million years or so (faster the closer in they started), but if I started them at 1AU or farther, by the end of a million years they were still very close to their original distances. Some of the smaller systems I tried were interesting as the planet would wind up orbiting around first one then the other star until it finally crashed into one or was flung into interstellar space. The movies I played on the final project presentation brought quite a few chuckles from my classmates.

  30. John Silver says:
    August 24, 2013 at 3:20 pm
    Cool!!!
    So, two questions:
    Why so few meteorites?
    What was the laser going “up” from the nbr 4 telescope tower?

  31. RACookPE1978: By way of answer to your question, check out the comment below the video:
    Justin Griggs 3 weeks ago
    The laser is used as an artificial star for the adaptive optics (AO) system to use. The atmosphere has thermal currents, moisture, etc. that distorts the light from the sky, we call that ‘seeing’. Normally the ‘seeing limited’ image, the max resolution we can get, is about 1 arcsecond. AO uses a wavefront sensor to measure the distortion of the laser star, and it sends signals to a deformable mirror that corrects for the atmospheric turbulence, allowing resolutions around 0.1 arcseconds.

  32. In hindsight, the Apollo astronauts should have carved some large graffiti on to the lunar surface in the dust to quell future conspiracy theories. Could have also taken up an enormous advertising banner to lay on the surface of the moon for people to look at with their image stabilized binoculars. A giant company logo perhaps, like a big red “M”. Talk about priceless advertising. The bleeding hearts would all be up in arms and astro imagers would not be impressed with lunar shots being vandalised.

  33. As for the different opinions of ferdberple and Greg wrt NASA mission, I suggest both have good points, so how about a NASA Mission Planet Earth and a separate NASA Mission Extraterrestrial Space. Funding ratio of total budget I suggest should be 10% for Earth Mission and 90 % for Extraterrestrial Mission.
    Peace…

  34. Konrad says:
    August 24, 2013 at 3:26 pm
    Trully amazing. I would be fascinated to know how mirror vibration is calibrated. Reference star?
    Artificial reference star produced by a sodium laser is the usual technique.

  35. “””””……..Owen in GA says:
    August 24, 2013 at 6:03 pm
    beng says:
    August 24, 2013 at 8:59 am
    Impressive. Astronomy is one of my passions. Can close binary stars have stable planetary systems?
    I did a COMPUTER MODEL using only Newton’s gravity (I did not want to tackle Einstein’s equations) that showed several orbital sweet spots for a three body system with two Sol sized stars and an Earth sized planet. The closest stable point for such a planet turned out to be about twice the distance between the two stars outside of their orbits. For wider spaced stars, at about 4AU it was just possible to place the planet in a 1AU orbit around one of the two stars. There was more leeway as the stars were farther apart……..””””””
    Owen, you should try your computer model with the three bodies (both stars plus the planet) in an equilateral triangle in the plane of the orbits of the binary stars. That configuration is supposed to be stable for any three bodies, so long as they don’t stray too far from the triangle.
    It is well known, that two groups of asteroids, accompany the planet Jupiter in its orbit around the sun, one group is 60 degrees ahead of Jupiter, and the other is 60 degrees behind. They are called the “Trojans”.
    Jupiter’s orbit is not a perfect circle, so the asteroids, also undergo perturbations of their positions; but evidently the system works ok.
    You might try to find out how eccentric the binary pair orbit can get, before the planet, gets kicked out of the system; or worse yet, crashes into one of the stars.
    The sun earth moon system evidently has more stable points for paraphernalia than the Trojan situation. They are well known, and are sometimes used to park satellites for observations.

  36. Fantastic, and finally we can get pictures from the moon of all the Apollo leftovers, the rovers. That would end the “did we go to the moon” debate effectively.
    Not that I have invested in it, its just …. well, you never know.
    And I like to know, 110% if possible, I am a sceptic by nature.
    So turn the telescope to the moon, from wikipedia:
    “The rover used on Apollo 15 was left on the lunar surface at Hadley-Apennine ( 26.10°N 3.65°E ). The rover used on Apollo 16 was left on the lunar surface at Descartes ( 8.99°S 15.51°E ). The rover used on Apollo 17 was left on the lunar surface at Taurus-Littrow ( 20.16°N 30.76°E ) ”
    http://en.wikipedia.org/wiki/Lunar_Roving_Vehicle

  37. @ High Treason.
    The easiest way to find out whether the Moon landings were real is ask the Russians. NASA and Hollywood could probably have fooled me (all I did was watch on TV) but I don’t believe they would have been able to fool the Soviet scientists. If the landings had been fakes, you can be certain that the Soviets would have broadcast the proof far and wide.

  38. This a really interesting post…unfortunately it makes me feel quite old because I can remember when Hubble was set up…it was the ultimate telescope at the time and now has been superseded 🙁

  39. We know the moon landings were real because an experiment is still running. The Lunar Laser Ranging experiment.

  40. Thank you for posting this and thank you John Silver for the link.
    What can be said:
    What a piece of work is a man! How noble in
    reason, how infinite in faculty! In form and moving
    how express and admirable! In action how like an Angel!
    By WS

  41. RoHa says:
    August 24, 2013 at 11:24 pm
    That is precisely the point I make every time some tiresome individual, usually a desperate to impress pseudo-intellectual, brings up the subject of faked moon landings.
    Whilst in rant mode, I went to Hawaii a few years ago to visit the observatories. In a bookshop in Honolulu I noted one shelf of popular science books and seven covering new age nonsense. How disheartening.

  42. Thank you Ben, Im not super impressed by the quality of the images from the link you provided, and I hope to see much better quality pictures with the new telescope. I think it would be great to end the lunar debate, and verify that all three rovers are on the moon. I have always found it strange there where no catastrphical missions resulting in lost lives. Very strange.

  43. All the mirrors I have ever seen reflect light. So how come parking a mirror in front of a mirros can be used to correct light that (presumably doesn’t) reaches the main mirror?
    Perhaps some journalist was allowed to write the article, and his spell checker changed ‘lens’ to ‘lense’, or vice versa, so he gave up and wrote “mirror” – he knew how to spell that!

  44. Your welcome Björn. Unfortunately I doubt that image resolution capabilities that could see a baseball diamond on the moon will provide much better detail than the LRO images.
    Actually I worked as a tech on relaying the earlier Apollo mission’s voice, data, and video communications back to the Houston via Oakland Comsat from Moree Australia, and thoroughly enjoyed the experience, listening to the voice comms which we had on the speaker systems during our shifts during the missions. And no, I didn’t find it strange there were no catastrophical missions, but given the risks, known and unknown, it would have been taken in stride by the NASA Apollo team and all the supporting operations.

  45. ***
    Owen in GA says:
    August 24, 2013 at 6:03 pm
    ***
    Thanks, Owen. I was thinking of a binary system just like you propose — ~equal mass stars in close orbit around the system’s center-of-mass, and planets orbiting outside the stars & also (obviously) around the mass-center (I don’t even know if such a system could actually form). Planets in orbit around each individual star would seem to me quite prone to being quickly flung out or dropped into a star, unless the separation of the binary stars was quite large.

  46. “All the mirrors I have ever seen reflect light. So how come parking a mirror in ”
    I suggest you look up astronomical telescopes and learn a little about design. It’s a fun subject and what’s going on today has it’s beginnings centuries ago.
    This, and almost every large telescope, is some variation of the “Cassegrainian” configuration. The Cassegrain uses a small, usually curved hyperbolic secondary mirror to “fold” the optical path so that the length is short compared to the aperture (compact aspect ratio), and the image is located in a convenient place at the rear of the telescope, not several stories up in the air near the entrance. So, in a Cassegrainian (BTW, the first reflector design, actually described by Cassegrain before Newton built his simpler single curved ‘Newtonian”) The light is first intercepted and focused by the large concave primary mirror. Near the primary focus the convex secondary intercepts the light and reflects it to the Cassegrain focus where the image is formed. This is a simplistic explanation as there are countless variations of how this is done.

  47. BTW, the basic limit of resolution due to the wave nature of light is 1.22lambda/diameter. In the case of this 4 meter telescope that works out as
    1.22*0.0005mm/4000mm = 1.5E-7 radians or 0.15 microradians
    There are 4.8 urads to the arcsec so that’s 0.032 arcsecs. Hmmmm….

  48. Of course this telescope can see a baseball diamond on the moon, because all the baseball diamonds on the moon are six times bigger to make up for 1/6 gravity – it’s almost half a mile to the wall in center field! 😉

  49. Ha ha, I’m afraid baseball diamonds don’t inversely scale with gravity. While the “drop” will definitely be less, the velocity will be the more or less the same. Of course, without any air it’s going to be impossible to do some of the tricks like a curve or knuckle ball.
    In fact, I claim because the resulting consistent nature of pitch trajectories, baseball diamonds will have to be smaller on the moon! The outfield, now that’s different.

  50. “””””……Randy says:
    August 25, 2013 at 6:44 am
    BTW, the basic limit of resolution due to the wave nature of light is 1.22lambda/diameter. In the case of this 4 meter telescope that works out as
    1.22*0.0005mm/4000mm = 1.5E-7 radians or 0.15 microradians
    There are 4.8 urads to the arcsec so that’s 0.032 arcsecs. Hmmmm……….””””””
    Well that number; 1.22 lambda /D is NOT the resolution limit. It is the diameter of the first dark ring in the diffraction pattern of an un-aberrated circular aperture.
    It is well known by visual astronomers, that you can visually resolve such a pair of stars; that is clearly identify them as two stars, when they are at half of that separation, so the edge of one disk is on the center of the other.. The eye does not see an intensity dip, which as I recall is about 4% of the peak intensity, but the pair is recognizable because of the notch in the outline.
    So 0.61 lambda /D is the Raleigh criterion for resolution. The dip disappears for a separation of 0.5 lambda/D, which is also the visual apparent diameter of the central “Airy disk”.
    ).5 lambda / d is often referred to as the “Sparrow Criterion for resolution.
    So 1.22 lambda/D is a very loose resolution criterion..
    Don’t take my word for it (or Wikipedia). Go read “Applied Optics and Optical Design” volume 1 by A.E. Conrady, or Born and Wolfe, or “Modern Optical Engineering” by Warren J Smith


  51. RoHa says:
    August 24, 2013 at 11:24 pm
    @ High Treason.
    The easiest way to find out whether the Moon landings were real is ask the Russians. NASA and Hollywood could probably have fooled me (all I did was watch on TV) but I don’t believe they would have been able to fool the Soviet scientists. If the landings had been fakes, you can be certain that the Soviets would have broadcast the proof far and wide.

    There are problems with the notion of asking the Russians versus merely applying the context of history of the time to the question.
    Problems with asking Russians. 1) they didn’t know. 2) it might or might not be in their interest to lie about it.
    Context of history. NASA did not have the computing power of a modern laptop and they did not have sophisticated software capable of image processing. Watching scifi movies of the time should help one understand the state of special effects. However, we had the ability to launch rockets into space at that time, partly thanks to the german V2 program. Building a big rocket booster running off of kerosene and liquid oxygen was not exactly some magical event. Building a lander was not a miracle of impossibility. Getting the playtex living girdle company to make an air tight suit was not either. And putting all this together and launching 3 guys into orbit in a tin can and providing enough rocket engine to launch them to the moon was no impossible feat in the least. Giving them an onboard flight computer with something like 90,000 bytes or words of core memory and a 3 line numeric display and a calculator style keypad was not an insurmountable problem either. The project was full of engineering level problems to overcome but there was absolutely nothing that couldn’t be dealt with using the technology existing or invented at the time. Also things like severe solar flares are fairly infrequent and also were not very well understood as to their danger at the time.
    In short, far easier to do the missions after the equipment was invented than it was to fake the missions. Lots of people saw the Saturn V rocket launched for these missions. It was real and it launched. After that, it was child’s play to have rocket powered crafts under jet pilot trained human control – fearless people that could fly anything. Only by assuming one had the modern technology and programs that exists today back in the 1960s could one presume that it would have been possible to fake the event.

  52. @cba
    Soviet science was extremely sophisticated, so I find it very difficult to imagine that the Russian scientists would not know if the landings had been faked. Nor can I see why they would have lied about it. The Soviet space programme had been leading the US programme since Sputnik, and the Soviets were working hard on their own Moon landing project. Given the tensions at the time (and I remember them well) it would have been a glorious propaganda coup to reveal the fraud.
    “Only by assuming one had the modern technology and programs that exists [ sic ] today back in the 1960s could one presume that it would have been possible to fake the event.”
    NASA has a time machine, of course.

  53. George, you are advertently or inadvertently splitting hairs here .
    1.22 lambda is the basic rule, FOR EXACTLY the reason you stated. But if you don’t give us a little tutorial on MTF, your STATEMENT IN CAPS saying I’m wrong really means nothing. In fact, I’m saying you are wrong, categorically stating what the resolution limit is when you apparently are not aware of what a narrow condition those criteria apply to. What does “resolve” mean? Separated, or merely detected as a double star. Is a double star the same as planetary detail (no). What about uneven doubles? What about baseball diamonds on the moon? Sorry, you want to bash my admittedly hastily and casually written explanations, at least extend the explanation past what is a forum gotcha. You want to drag up a bunch of empirically determined criteria for double stars by long dead astronomers be my guest, those are a matter of history and hardly anything to argue about. But at least explain what they really mean if you are going to use them to refute what someone else is saying. Have fun paraphrasing Conrady, Born and Wolf, and Smith. Might want to add Kingslake , King, and Welford while you are at it.
    Here’s something for you to do that doesn’t have anything to do with reading something out of a book. Get or make a USAF 3 bar resolution chart. Use a good optical system to examine it. Report back what the resolution limit is. I know what the answer is – I’ve determined it many times in my professional career.

  54. Could somebody please translate the phrase, ‘baseball diamond’ into something that most of us might understand, like ‘A cricket ground’ or an ‘Aussie Rules Football Oval’.
    Thanks

  55. Patrick says:
    August 26, 2013 at 6:20 am (replying to)
    “Gerard Dean says:
    August 26, 2013 at 2:56 am”

    Google is your friend. While there are cricket grounds, the normal term used is “cricket pitch”. As I am from a village near Hambledon, the home of cricket, I should know.

    Ah, but regardless of the weight of the ground crickets, or the noise they used to make, you can’t use a “cricket pitch” as a reference length in astronomy. For one, the length of a cricket pitch in vacuum is longer than a cricket pitch near the suds (er, the pub). 8<)

  56. “RACookPE1978 says:
    August 26, 2013 at 6:50 am
    Ah, but regardless of the weight of the ground crickets, or the noise they used to make, you can’t use a “cricket pitch” as a reference length in astronomy.”
    Of course you can. How man chains in an AU? Sod that, lets have a beer!

  57. Well, the “difficultly” in man chaining the AU is just that. Ya gotta get a man to stand in the middle of the AU to hold the chain straight!
    And pulling out the sag when Mercury and Venus swing by is just bleedin’ nasty work.

  58. “RACookPE1978 says:
    August 26, 2013 at 7:37 am”
    If ever you are in that part of England, and if THAT pub is still a Gales pub (Not been there since 1988), then drop by and have some HSB. Sit outside, enjoy!

  59. “”””””……Randy says:
    August 25, 2013 at 10:16 pm
    George, you are advertently or inadvertently splitting hairs here .
    1.22 lambda is the basic rule, FOR EXACTLY the reason you stated. But if you don’t give us a little tutorial on MTF, your STATEMENT IN CAPS saying I’m wrong really means nothing. In fact, I’m saying you are wrong, categorically stating what the resolution limit is when you apparently are not aware of what a narrow condition those criteria apply to. …………”””””””
    Well Randy, I don’t quite understand what your beef is.
    This thread is about the resolution of astronomical telescopes. Or more significantly how adaptive optics is allowing earth bound very high resolution telescopes, with very large apertures, to achieve almost their theoretical resolution capability, while imaging through earth’s turbulent atmosphere.
    The atmosphere does NOT (or not if you prefer) alter the resolution limit of large earthbound telescopes; well no more than the change in wavelength caused by the non unity refractive index of the atmosphere; but it does distort images, as a result of the turbulence.
    Now I made NO statement in caps; and the resolution limit of diffraction limited telescopes has nothing whatsoever to do with MTF, but just incidentally, that happens to be 1 for all such instruments.
    Moreover, a three bar Air Force chart, will not yield MTF values; you need a sinusoidal bar chart for that. Yes you can infer what the resolution might be from an Air Force chart image.
    Warren Smith says the following: Page 139 6.10 Resolution of Optical systems.
    “When the image separation reaches 0.61 lambda / N.A. the maximum of one pattern coincides with the first dark ring of the other and there is a clear indication of two separate maxima in the combined pattern. This is Lord Raleigh’s criterion for resolution and is the most widely used value for the limiting resolution of an optical system ”
    Conrady cites the Astronomer Royal G.B. Airy as having first computed the diffraction pattern of a perfect system, and states that the diameter of the first dark ring is 1.22 lambda/N’sinU’ on page 132 of Vol 1 of the Dover paperback edition; which you, with a professional career in the subject, would certainly have a copy of; so of course you would also recognize Conrady’s standard notation; so I don’t need to explain that. Well I have two copies, so I’m sure you have at least one.
    I lost my hard bound copy from high school, in a missing box, that contained ALL of my high school and university text books, from a trans-pacific ship voyage in 1961.
    I would have to dig through a big pile to find the correct volume of Rudolph Kingslake’s books; and the only text I have of Welford, is his collaborative one with Roland Winston on non-imaging optics, which doesn’t even deal with the subject of resolution, as it is quite irrelevant to non-imaging optics.
    But none of them give 1.22 lambda/D as the “basic resolution limit” as you assert.
    But then I’ve only been dabbling in the subject since 1954, so you probably know a lot more about it than I do; so I”ll go with your value, so as to not confuse Anthony’s readers.
    And I almost forgot, it was Conrady who said the visually apparent Airy disk diameter is
    0.5 lambda / N’sinU’; also on page 132. Warren Smith uses Conrady’s plot and photographic image, in HIS textbook.

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