Beam me up!

By Phil Plait | September 7, 2010 7:00 am

Some astronomical pictures are simply and truly cool.

And this, my friends, is near the top of the list.

vlt_laser_galcen

[Click to enlasenate.]

Yes, the wow factor is high with this one! And the thing is, what you see is what you get: it’s a laser shooting out of an observatory straight up into the heart of our galaxy!

The observatory is of the European Southern flavor, in Chile. It houses the Very Large Telescope, which has a very nice little tool it can use: a laser guide star. The laser shoots up into the sky and excites atoms in the upper atmosphere, causing them to glow. That makes an artificial and very bright star in the sky! The telescope can then use that star to track the distortions in the atmosphere and compensate for them, allowing the images it makes to be incredibly clear and sharp.

Although it doesn’t say so explicitly in the press release, given where the laser is pointing I’m guessing they were observing stars orbiting the supermassive black hole in the center of the Milky Way. Those stars can actually be seen to change their positions over time, allowing astronomers to calculate the mass of the black hole — and using such methods they’ve found it to be a whopping 4 million times the mass of the Sun! The star positions need to be very accurate, making the laser guide star system invaluable.

The long time exposure of this image makes the laser obvious, as well as the incredible vista of the Milky Way streaming overhead. You can clearly see the central bulge of the galaxy, the spherical hub at the center containing billions of old, redder stars. The dark lane cutting across the center is due to vast amounts of dust created when stars are born and when they die, and that’s mostly confined to the disk of the galaxy. Since we are inside that disk, it makes a long line, a stream, across the sky. I’ve seen it many times, though never from a truly dark site. Some day…

Tip o’ the sharks with frikkin’ laser beams attached to their heads to the ESO Observatory Twitter stream. Image credit: ESO/Y. Beletsky

CATEGORIZED UNDER: Astronomy, Pretty pictures
MORE ABOUT: laser, Milky Way, VLT

Comments (68)

  1. Bob

    Oh Uh – are they trying to kickstart 2012 early?

  2. alfaniner

    First thing I thought of: TRON. You know the scene.

  3. Nick

    @Bob #1:

    Only if 2012 isn’t for another 60,000 years.

  4. Larry

    What did the Milky Way ever do to warrant such an attack by Earth?

  5. jeromeclemente

    coolest picture ive ever seen, cause i thought that it was edited. cool

  6. Thorne

    Are we sure it isn’t edited? How do you get a long-exposure picture like that, one long enough to show such detail in the Milky Way, without getting some blurring of the foreground image?
    Conversely, how do you get such a clear picture of the foreground image, and the laser, without showing distortion of the background stars?

  7. Ross Cunniff

    It may or may not be edited, but it is almost certainly a multiple exposure. To get that sharpness/brightness/contrast in the stars, the camera had to have been tracked against the rotation of the Earth. But the observatory is not blurred. So, possibly, at the beginning or end of the tracked exposure, they flashed the observatory (or, alternately, took a non-tracked exposure of the observatory and composited it in).

  8. gopher65

    So that isn’t a composite image then? Because it *really* looks like it’s been photoshopped.

    As with Thorne and Ross Cunniff, my first thought upon considering the validity of the image was “you can’t expose the stars like that in a single image without tracking them across the sky, which would then make the observatory look blurred in the extreme.”

    That image *has* to be at least two different exposures. I’d also hazard a guess that the laser was touched up in an editing program.

  9. Georg

    There is a very bright winow at lhe lower left
    corner of the picture.
    I always thought, someone messing around with light
    around a telescope is shot without delay?
    Georg

  10. Messier Tidy Upper

    Is that really the observatory shooting a laser up or is it somebody else shooting a laser down ‘Independence Day’ style? ;-)

    (Yeah, I know its the former really.)

    I presume that’s the Large Magellanic Cloud there on the far right too?

    ***
    PS. Glad to see you got through your wildfire okay – what’s the latest news on that please? All safe & well, fire out or at least under control?

  11. LKM

    Looks like an HDR image (thus no blurriness or streaking stars). What I wonder is: Why is the laser visible? Is this normal? Is there dust or something that makes it visible?

  12. Gary

    Phaser on stunning!

  13. jfb

    The stars are ever-so-slightly streaky in the full-resolution image (beyond the distortion introduced by the extreme wide angle and what has to be a wide-open aperture), so it doesn’t look to me like they were tracked. By the size of the streaks (compared to images I’ve taken with my camera in the back yard) it looks like somewhere around a 30-second or less exposure. Given the amount of noise the ISO must have been seriously cranked up (1600 at least).

    I don’t doubt it’s been heavily ‘shopped to tweak contrast and color, with some digital dodging and burning to bring out the stars relative to the foreground, but I’m willing to believe this is a single, non-composite image.

  14. Mike Oliver

    Here’s an article about the series of photos taken by the photographer, Yuri Beletsky. “The images were obtained with a digital camera and 10-mm optics, mounted on a small equatorial mount, and are each the result of a single 5 minute exposure. ” You can see blurring in the other pictures, which makes me think this one uses a little fudging. It might also be that the tracking movement was vertical within the image, but it still looks sharper than the others.

    Article: http://www.adaptiveoptics.org/News_0807_1.html
    Photo gallery: http://www.eso.org/public/images/?search=beletsky

  15. Mapnut

    Is the laser really pointing at the center of the Milky Way? Since the camera is at an offset, I’d expect the beam to continue out the top of the picture and actually point somewhere else.

    Boy, this photo has raised a lot of questions.

  16. interskeptor

    …huhm… is it jus’ me again, getting something wrong (probably)? ;-)
    At the moment I can’t imagine how this would be aiming towards the center of OUR milky way. It looks more like its just shooting up to some other point, ending 90 km above, and this point – by sheer accident or deliberately chosen perspective in this photo – *appears* to end right in the center of our galaxy…
    So, where would be my error here?

  17. What makes an amber colored laser? I don’t think I’ve ever seen that color before.

  18. Bob_In_Wales

    Swords into Ploughshares!

    Correct me if I’m wrong but if they’re using a Guide Star then this is an Adaptive Optics system. Wasn’t that originally developed as a part of President Reagan’s “Star Wars” system? Nice to know something working and useful came of the program!

  19. Amenhotepstein

    Thanks, Phil. This is one of those things that reinforces my fundamental optimism for our species. If we are capable of such truly amazing feats, I have hope that we can solve our most serious problems ourselves and move ahead. I wonder what my great-great-grandchildren will live to see…

  20. Damn those astronomers! Did they ASK PERMISSION before shooting the galaxy with a laser?

    //tired cliché

  21. firemancarl

    Forget how kewl the picture is, I’m totally lovin all the laser cracks being made. Maybe this is where Dr. Evil has his “fricken layzer!”.

  22. David C

    Aloha Phil…

    I’m unclear if you could even be close in trying to determine what they were looking at. It would depend on whether or not they are using the laser in that particular instance as an adaptive optics solution or a guide star solution (or it could be both).

    In the case of a guide star, it probably is not anywhere near where they are viewing (they are merely using the laser as an artificial star to guide the scope). In the case of AO, it is probably somewhat near to the view point (but certainly not directly at it, it would ruin the observation).

  23. You aren’t supposed to see a beam of light passing through the air unless it gets scattered by fine dust particles or droplets in the air. Recall the last time you attended a talk by someone using a laserpointer?

    But aren’t large telescopes in places where the air is especially clean and free of dust and droplets?

    The photographer Yuri Beletsky claims that the laser beam on the pictures looks pretty much like it is seen with the unaided eye, see

    http://www.adaptiveoptics.org/News_0807_1.html

    This means that the laser beam is so powerful that it creates the “artificial star”
    not only in some high layer of the atmosphere, but all along its way. This may
    also explain the color, which is not the original laser color but the light emitted
    by the excited molecules.

  24. Jason

    If I recall correctly, the beams used for Adaptive optics are sodium based, hence the color, and that in the upper layers of the atmosphere there is a sodium layer that reflects the beam strongly and creates the artificial star. Also, that near the ground the beam Is visible in the air, similar to how a Green laser beam is visible in the air whereas the red ones usually aren’t.

    The orange beam is visible in the very lower layer of the atmosphere, fades as you go up, until it hits the layer with sodium in it and then shines brightly for Adaptive optics correction.

  25. Chris S

    After reading the article by the photographer, I really think this is an editted image.

    In his article he says:

    “The images are not composite”, emphasises Yuri Beletsky. “The camera was being tracked on the stars, which can be easily noticed if you look at the telescope domes on the image (they look a little fuzzy). The colour of the laser beam on the first image actually looks pretty close to what one can see on the sky with the unaided eye.”

    And he’s right – in the article images, the domes are fuzzy.

    But in this image, the dome and doors are as sharp as the stars. And – having done some wide angle sky photos, I can say for certain that you don’t get that color out of the Milky Way without a long, and therefore guided, shot. As the photographer notes, a guided shot would have a blurry telescope.

    That said – almost every beautiful astro image is, in some way, something we can never see with the unaided eye. This image is beautiful and educational all at once. But if it was editted for clarity and value (say by adding in an un-blurry telescope) then they should say so.

  26. Josh F.

    I’m looking for the shark…. is it inside the dome?

  27. Oli

    I didn’t know Doctor Octagonapus was an astronomer.

  28. Chip

    @ Thorne at # 6:
    Possible answers to you questions are: Unlike the sky, the foreground is not moving hence clearly exposed. Cameras today can be set to detect starlight and the Milky Way as well as residual light reflecting off the ground in one shot. The laser is bright but not so bright as to over-expose on the image.

  29. ConneXionLost

    What is that thing in the upper left corner of the picture?

  30. @ Jason (#26) – Ah, that explains it then. Thanks! :)

  31. ND

    Dual use telescopes. They also kill mosquitoes.

  32. Monu

    Looks like a planetary scale lightsaber. Yeah, dumb comment is dumb, I know.

  33. Bjørn

    AWESOME… this really reminds me… i’ve gotta get out of the city, and its damn night lights soon… The laser is pure awesomeness, but those stars are beautiful… nothing less…

  34. BGC

    SURRE, you SAY it’s for exciting the atmosphere to allow for correction, but it looks to me like they’re ripping open the galaxy to let the Old Ones thru…
    Cthulhu fhtagn, indeed.
    BGC

  35. Steve Metzler

    I think we’re being had here, but in a good sorta way. This is a test by the BA to see if we’re really skeptics, right? In other words: how many things are wrong with this picture? For starters, you don’t see dust clouds of newly forming stars with the naked eye from earth. That particular starscape is millions of light years away. I’ve been in the Rift Valley in the middle of Kenya where there are no urban lights to ruin the view. And while it may be a spectacular view, it ain’t nuthin’ like that.

    Of course… I may be wrong, but I suspect we’ll be getting our ‘report card’ shortly.

  36. One Eyed Jack

    Stand by, ion control… Fire!

    The first transport is away.

    ::cheers::

  37. It also causes people who see the beam to think they’re seeing some sort of UFO.

  38. firemancarl

    I agree with all of the comments, but personally I don’t care if they did touch up the photo. Sometimes, it’s ok to just sit back and stand in awe.

  39. firemancarl

    Oh, can we gwt confirmation on that fuzzy patch on the right of the picture? Is it the LMC? Is it Cthulu entering our galaxy thanks to the laser ripping open the fabric of space time?

  40. MadScientist

    @Zadl#19: The laser is a Sodium laser (and damn, even these low power ones are awfully bright). One reason it is used is that absolutely no light at those wavelengths reaches the ground from space due to the atmospheric “sodium layer” (produced by the ablation of sodium in meteors) so in some cases it may cause some minor inconvenience in measurements (more than compensated by the advantages of the guide star) but in principle does not interfere with the science because we’re not getting that light from space anyway.

    @Ross#7, @gopher#8: How dare you suggest that a long exposure of the zenith close to the equator would not show a stationary sharp image of the observatory with a nice sharp stationary image of the Milky Way? Or are you suggesting that the lighting of the scene is not consistent with the position of the Milky Way?

    @LKM#11: With the long exposures it’s typical for the laser to become visible due to the light scattered off of dust and aerosols. If you’re on site you can also see the beam although it appears extremely dim.

  41. John Sandlin

    Some one needs to say it:

    I see your schwartz is as big as mine!

  42. Ross Cunniff

    MadScientist@46

    Wow, things must be even weirder at the equator than I thought. Everywhere *I’ve* been on Earth, the stars move across the sky at the same rate (proportional to each star’s declination). No matter where I’m standing.
    :-)

  43. Darren

    In an e-mail, Beletsky explains how he blended two frames to create the picture you see here.

    “The image was taken with a Canon 5D Mark II camera + Canon 15mm/f2.8 Fisheye lens. The image is actually a mosaic of two frames, where each one was taken with 30-second exposure. Due to the very small focal length (15 mm) the stars are not trailed (because of Earth’s rotation — the longer the focal length, the shorter should the exposure in order to avoid trailing). Then those images were carefully aligned in data reduction software.

    “Now, regarding the colors. At night, human eyes are not sensitive to colors. Therefore, in reality, the Milky Way looks colorless (while on the image it does have a color). In contrast, the laser beam is bright enough to see its color with our eyes. The only issue is that on the image the laser beam looks really bright (due to long exposure time), while in reality it has a very deep and dim orange color.”

  44. santel

    ummm… in the high reso image, the noise/grain is off. in the dark parts of the observatory they are smaller/finer but beyond the observatory the noise artifacts are much bigger.

  45. Yeebok

    @48 I’m hoping that’s the humour smiley ..

    From what I can tell it’s the SMC. To be quite honest it’s a heck of a lot clearer than I see it in my back yard. The weirdest thing about the image to me is that the upper left and lower right corners appear to smear in the opposite directions yet the centre appears pixel-perfect. To me that implies the centre of whereever the camera was pointed was more or less straight up, somewhere near the equator ? I don’t notice any fuzzies or ghosting on the ground part of the pic. Given the way parallax looks, I’d expect camera movement to show more change on the closer objects.

    To sum up my take is an unguided photo otherwise the stars in the corners would not be blurred. You need to enlasenate*1 to see the effect tho.

    *1 Just teacherified my spell check a new word !

    I also noticed a bright red spot near the top right of the full size image .. at slightly higher than where the laser disappears, and about 2/3 of the way to the edge of the image. I assume it’s a camera artifact ?

  46. Nigel Depledge

    Just . . . whoa!

  47. BCL1

    If it is a long term exposure, then (unless the laser is pointed at Polaris), the laser would move relative to the backgroud stars. You can’t move the laser in such a way that it appeares fixed against the background. The forground, background and laser are 3 different images added together.

  48. Steve Metzler

    Well, yeah, I finally grokked that it was a 30-second exposure with a magnified fish-eye lens. From an observatory far away from any city lights, I can see that happening. And the exposure length also accounts for the increased intensity of the laser.

    But as the photographer himself admitted, the buildings were added in from a second exposure. So it’s not a single shot as was originally inferred, but rather a composite. Still, colour me impressed. However it was obtained, a fantastic shot at the end of the day.

  49. MadScientist

    @BCL#53: Darren points out in #49 that the photographer used 2 shots only, each 30s. I’m surprised that the Canon’s sensor is sensitive enough to produce such a great photo of the galaxy at a mere 30s. My old el-cheapo digital camera is really showing its age. I have a horribly expensive b/w camera which is very sensitive but that’s used as a scientific instrument – and it does make the Canon camera (even with lenses) look cheap. It’s still pretty amazing that the Canon has such a sensitive detector for its price.

  50. luisK

    if we can see there with just sending a tracking laser why do they have to send those fricking UFOs to look at us???

    or maybe they don’t just look.

  51. gopher65

    MadScientist: Yeah, the detectors in those cameras are improving rapidly:). I’ve seen several articles in the past while about small breakthroughs that will keep the quality of the detectors improving for the next few years. It’s great stuff. Course, the lens you’re using is just as important. Crappy lens = crappy image even if you have a great chip.

    Also, he has the ISO cranked waaaaaay up in that image. On a digital camera ISO is a bit different than on a film camera, but it still refers to sensitivity (higher ISO = more sensitivity = less exposure time = “faster film”). Cranking up the ISO increases the chip’s light sensitivity, but it also dramatically increases the level of noise in the image (as you can see with his picture of the sky. Lots of noise). That high ISO decreased the quality of the image(s), but it made those short exposure times possible.

  52. Joseph

    Looking at this image I imagine this is similar to what a ring world would look like arching up and over the sky.

  53. Oh! Well, if you have been at the Galapagos Island, u have a nice idea a truly dark skies. Few months ago I was in Brazil attending an astronomy&astronautics meeting and one night, I went out with Babak Tafreshi, the guy from TWAN, and traveled far away the city of Campos dos Goyataçes. What a marvelous sky!

    Here is a picture of that night:

    http://picasaweb.google.com/jvannini/3rdInternationalMeetingOfAstronomyAndAstronauticsOfBrazil#5467240905450094306

  54. Wolfotographer

    My approach, (and I have done this with less…stellar… results: log exposure, track or not, pop big, ol’ strobes at the foreground target to get “high-speed shutter” quality during a duration that should have blurred during track. Modern hIgh ISO and fast lens could account or so little blur.

  55. Chris S

    Ok – thinking a little more, and digging.

    Check out the calculator at

    http://www.wilmslowastro.com/software/formulae.htm#StarTrails

    I used
    Focal length (mm): 15 (lens data given)
    Exposure time (secs): 30 (exposure data given)
    Declination: -28 (looked up galactic core)
    Pixel size (microns): 8.2 (looked up Canon 5D)
    Pixel binning: 2×2 (because camera native is double this image)

    It indicates star trails of 1.8 pixels. That would be hard to see! The use of two images stacked means he gets effective exposure of 60 seconds.

    As for the laser – it likely doesn’t benefit from the stacking. Re-doing the above calculation with a 60 second exposure gives only 3.5 pixels of trail — and the laser on the image is significantly wider than that.

    I’m still curious about the massive explosion of color in the image! It would be interesting to know the aperture and ISO settings for this shot; focal length and exposure will tell us the star trails, but knowing the other settings would help understand the whole image.

  56. Brian Too

    Y’see, this is the very first effort of the Planetary Protection Coordination Office (PPCO). They are shooting lasers at all those NEO’s, to, uh, blow em up! Yeah, that’s it! Bruce Willis style, but with frickin’ laser beams!

  57. I love the name “the Very Large Telescope”. May I propose a name of my own for the next one? “The Really Horking Big Telescope”. :D

  58. réalta fuar

    Good work Chris S. It’s likely that the ISO isn’t cranked up very much, as the Canon CMOS chips with their low dark noise are the absolute best among the DSLRs for doing astronomy (their low dark noise more than make up for the fact that they’re not as sensitive as CCDs).
    Now, WHICH VLT telescope was it? Everyone knows there are four, right? I don’t know for sure without looking it up, but there’s probably only a laser guide star system on one of the four.

  59. Alex

    @realta fuar, #64
    It is UT4 (Unit Telescope 4), also called Yepun. If you look at a picture of Paranal, three of the telescopes are almost lined up, and one is out of the aligment… that one is UT4, and yes, it is the only one with a laser, which is called LGSF (Laser Guide Star Facility). The laser is generated as a green laser, then is passed through a liquid containing orange tint, and that is fed using an optic fiber into a cassegrain telescope 50 cms in diameter (right behind UT4′s M2), which “launchs” the beam up.
    Did I mention I work here at Paranal, where the VLT is located ??? Of course, Yuri is a very well know photographer around here…

  60. Paddy

    What puzzles me is the way the laser beam STOPS suddenly. Is that where it runs out of atmosphere to illuminate? And the beam is angled quite steeply away from the camera? I find it strange that no one else here has mentioned this.

  61. paul

    This is how an intergalactic war starts, with a harmless laser beam shot into space

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