Amateur astronomer spies on spy satellites

By Phil Plait | May 28, 2010 7:00 am

[NOTE (added May 30, 2010): Thierry Legault, himself an extraordinary astrophotographer, has commented below with some issues he has with these images. His points are well-taken, and have given me pause. None of the claims Ralf has made for this imagery are physically impossible — I checked the math, and I have a pretty good knowledge of image reduction and analysis — but that does not mean they are correct. I want to be careful and say I am skeptical of these claims, but cannot say whether they are correct or not. In the future I’ll be more careful in my own wording in my posts.]

Ralf Vandebergh, an astronomer in The Netherlands, has sent me many of his outstanding images of space vehicles in the past. But he just sent one to me that I have to admit, rather shocked me: an image of a Keyhole 11 spy satellite!


At the time Ralf took these images, the satellite was about 600 km (360 miles) away, a considerable distance for a small object. Mind you, this satellite is about 5 meters (16 feet) long, so the fact that any detail is seen at all is amazing. It would appear to be less than 2 arcseconds in length at best — that’s the same apparent size as a U.S. quarter seen at a distance of about 3 km (nearly two miles!). For comparison, the Moon is 1800 arcseconds across, or 900 times bigger, so we’re talking weensy weensy here.

The Keyhole satellites are pretty well-known in space circles, and the KH-11s have been around a while (the next-generation KH-12s have been around a while too, but not much is known about them). The 11s are pretty much like Hubble Space Telescope, but pointed down at us — well, presumably not us, but as opposed to pointed out toward the heavens. Given some basic physics, and assuming the same optics as Hubble has, it’s easy to calculate that they should be able to spot objects as small as perhaps 10 cm (4 inches) across, though this would require either some very precise tracking or very short exposures to prevent blurring. Or maybe both. It’s also possible to improve on that resolution a bit using sophisticated mathematical techniques, too.

While little or no orbital data is known for the KH-12s, the orbits of KH-11s (at least, some of them, dun dun dunnnn) are online. Ralf used that data to predict where and when to get these images. In the picture above he compares what he got to a simplified Hubble-like drawing, and with some small amount of imagination you can see the resemblance. I wouldn’t put too much stock in the exact configuration, but it does appear he got some detail on the satellite. He also has a neat animation showing the satellite; details are harder to see but he catches some hint of solar panels, as well as catching a flash of sunlight off a reflective surface.

Also note he’s done all this with a 25 cm (10″) telescope. With something bigger, higher resolution is possible. Not so much because the image can be magnified more, but because shorter exposures are possible (bigger ‘scopes capture more light from an object), freezing the atmospheric distortion better. I have seen some pretty big ‘scopes that are used to track satellites, which makes me wonder how much detail they capture… and who else is out there tracking our satellites as well.

Image courtesy Ralf Vandebergh

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CATEGORIZED UNDER: Cool stuff, Pretty pictures, Space

Comments (58)

  1. Jurjan

    Unfortunately for me (I AM dutch) he’s Belgian, not dutch

  2. Mchl

    Could we use Hubble to get even better pictures of these satellites?

    just kidding 😉

  3. MadScientist

    Amazing. I used to dream about having the optics of the Corona satellites; they would have made a great pair of binoculars. These days I can just have a shop in China turn and figure even better optics and at relatively low cost – now if I only actually had the money.

  4. Gary Ansorge

    10 cm? Wow. They could capture my nose. Remind me to not be looking skyward when they cross over.

    ,,,and we’re having problems spotting Ossama bin Lauden? With tech this good, we should be able to see what he’s having for lunch.

    The tech just keeps getting better and better. Speaking of which, here’s a link to a Dog’bot that can climb over very difficult terrain(such as that on Mars).

    Gary 7

  5. Strabo

    Could we use Hubble to get even better pictures of these satellites?

    I’m not kidding. I know HUbble isn’t designed for that sort of thing, but is there anything that would prevent Hubble from getting good pictures of them? Perhaps it wouldn’t be able to change it’s orientation fast enough to track the spy satellites?

  6. While 1800 arcseconds is 900 * 2 arcseconds, the moon is roughly round, so it’s a lot more than 900 times bigger in apparent size than the satellite. :)

  7. Brian


  8. Jurjan

    mmmhhh, seems I spoke too soon…
    this site is Belgian (.be suffix) but he’s dutch after all.

  9. Nick (#4) I was talking in linear terms. :) But you’re right: in area it’s more like 650,000 times larger (assuming the satellite is 1 x 2 arcseconds).

  10. Pi-needles

    Spy satellites ..spied .. keyhole .. apt! 😉

    Who watches the watchers & spies on the spies? The amateur astronomer of course! 😉

  11. Patrick

    I have a feeling someone is going to be disappeared.

  12. The reactionaries will get on to this and say that we have to restrict access to telescopes because if terrorists get hold of them they will be able to find our spy satellites…

  13. We shouldn’t be looking at this. I, for one, did not see anything.

  14. “Okeh den. I rehddy dee scöpen fer dee nighten’s vhewing… Hehy! Was dah zownd boof meer hed? Ees beehunken blåkken heeliklipterischen zumin dun heer! Hoo bin dem menner in blåkken? Oh dár! I bin hösen!”

  15. Jamie Mueller

    I wonder if he could snap a photo of the X-37B now that its track has been determined?

  16. MHS

    The X-37B doesn’t get much higher in elevation here (Netherlands) than about 10 degrees. I’m guessing this would make photographing it pretty much impossible.

  17. Messier Tidy Upper

    Impressive. Very. :-)

    .. the orbits of KH-11s (at least, some of them, dun dun dunnnn) are online.

    Surprising. Very. 😉

    I really wouldn’t have thought the military would allow everybody to know that. Why do they? Don’t those satellites work anymore or something?

    @ 4. Gary Ansorge Says:

    ,,,and we’re having problems spotting Ossama bin Lauden?

    Even the best optical telescopes in the world with the best technology around would find it hard to peer into caves or through house roofs. A brighter alternative (at least for us ) is that Osama Bin Laden is already dead although the constant annoying videos make that less likely. We’ll get him in the end one day though. I hope.

    @ 14. kuhnigget : That’s all Dutch to me! 😉

    PS,. This reminds me of an old (80’s-90’s?) movie – an action thriller /martial art-sy type thing I forget the name of – where there was a scene with a super-sophisticated military satellite that was being used to spy on a girl sunbathing nude on a beach somewhere? Think that was also a super weapon earthquake making satellite or now was it one perhaps with stolen nuke missiles or something? Think there was also a scene in it where a very sexy military girl was thrown off a train too .. Might’ve been a Steven Seagal one but not too sure of that – can’t recall the name of it. Anyone else here know the one I mean?

  18. semi

    Should I report the phrase “aperture opening” to the Department of Redundancy Department?

  19. BigBob

    PsyberDave Says:
    We shouldn’t be looking at this. I, for one, did not see anything.

    If they want us to stop looking at them, they’ll have to stop showing them to us!

    Vor ist der Kuhnigget gorn? Last sin mit der mench in blåkken mit der pischtol gerpaken.
    Last herd yodel mit der elektrod tu onderstel gerschtrappen. Nasti.

  20. Gebraden Kip

    @ 14. kuhnigget

    You had me fooled! I actually fed that through Google Translate for all Scandinavian languages until I tried reading it with English pronunciation. 😀

  21. You can go outside any clear night and watch spy satellites! The Heavens Above web site will give you complete ephemeris data and sky tracks for satellites making visible passes above your location:

    Many of the KH-12 satellite orbits are known (due to amateur observations), and available on Heavens Above. The site will also give you predictions for Hubble, the ISS, the Lacrosse spy satellites, and many others.

  22. I’ve heard the air force has developed state of the art (perhaps better then astronomers have) adaptive optics to see these satellites themselves from their ground based telescopes. (An astronomer at UC Irvine told me this was the case.)

    Kudos to Ralf for being able to do a similar thing without all that hifalutin equipment! Well done.

  23. @kuhnigget

    A moose once bit my sister.

  24. DennyMo

    Gary Ansorge Says:
    ,,,and we’re having problems spotting Ossama bin Lauden? With tech this good, we should be able to see what he’s having for lunch.

    What Messier said, plus: you gotta know where to point the telescope, too.

  25. Jon Hanford

    @21. Joseph Smidt :

    Check out this page on the Starfire Optical Range at Kirtland AFB in New Mexico[ ]. Much of the research into laser-based adaptive optics (now widely used at major observatories) took place here. They are currently using a 3.5 meter scope so you can imagine what they are able to image (they claim “….basketball-sized objects 1,000 miles in space.”) YMMV :)

  26. -jeffB

    I’m not so sure moving to a scope bigger than 10″ would help that much. For an object in direct sunlight like this, you use a really short exposure anyhow — remember, it doesn’t matter how tiny or far away it is, the *surface brightness* is what matters, and that’s invariant. I seem to recall that the atmospheric fluctuations that limit seeing tend to be on a scale of about ten inches, so that a wider non-adaptive aperture doesn’t gain you as much resolution as the equations suggest. You’re up against spatial, not temporal, limits.

  27. Douglas Troy

    This … this is why I don’t tan without a bathing suit.

    Well, that the possibility of sun burn …

    Just say’in.

  28. There’s a whole crowd of amateur astronomers who communicate with each other about satellites like this. Here’s the forum I’m aware of:

    Here’s their discussion about finding the X-37B:

  29. Sili

    Well, that should anwer the quis custodiet thing.

  30. Aleister Crowley

    In addition to the optics, these birds also have infrared and ground scanning radar.

  31. Chip

    Here’s a source for spotting various orbiting things from your location:

  32. Steeev

    @17 — Under Siege 2: Dark Territory. You were correct in all details except the stolen nuke missiles — that was Under Siege 1.

  33. Actually, this (USA 161) is a KH-12, not a KH-11.

    Also, we are quite sure Phil that we have all KH-12’s catalogued. The KH-13 “Misty” stealths: that’s another story…

    @ 17. Messier Tidy Upper:
    It is not the military making these orbits available. These orbits are determined and published by amateurs (such as me, e.g. click my name for examples of my classified satellite observing).

  34. Too late to edit this in in my previous post:

    There are 3 KH-12’s currently in orbit: USA 129, USA 161 (the one pictured by Ralph) and USA 186. The one featured here, KH 12/4, was launched in October 2001.

    A fourth and fifth KH-12, USA’s 86 and 116, are no longer up as they have been de-orbited: USA 86 was de-orbited mid-2000 and USA 116 was de-orbited late 2008.

    Under favourable illumination conditions, they are visible to the naked eye during a pass. So much for secrecy…

  35. Jason

    Its pretty much impossible I think to keep an orbiting satellite secret. Its almost certain to be seen and its orbit calculated. Now exactly what said Satellite does is a different story and much more likely to be secret. Though a good scope observation can probably yield some speculative details exact capabilities are likely to remain unknown.

  36. Samsam

    @32. Aleister Crowley
    Radar? This completely eliminates any possibility of secrecy. Kinda like a cop shining a spotlight in your window. Even if you don’t know the frequency, a broadband directional antenna (zero cost, if you are clever), a preamp (the cost of a good eyepiece), and a RF spectrum analyzer (cost of a good amatuer scope) would reveal all kinds of interesting observational targets.

    I’m sure they would try to make the radar difficult to observe (spread spectrum), but there’s lots of folks working on open source software defined radio projects.

  37. Radwaste

    Small point to make: “amateur” does not mean any less ability than a “professional”. The distinction is merely that they are not paid by a contract for what they do.

    Look around, and you can see people where you work doing no more than they are paid for. These were never amateurs, and they lack skills that those who love their work (the root of amateur, after all) routinely display.

  38. Sigh… someone tell me again why a government is allowed to have secrets from its people, and still be called a legitimate government?

    It’s good know people are out there finding these satellites and publishing their orbits. Keep up the good work!

  39. Aleister Crowley

    @38 samsam indeed. In my haste I also neglected to mention this is just one of many similar units aligned in a grid with the capability to maneuver over any location on the planet within five minutes. As for privacy, sadly it’s surveillence all they way down to rocks which can detect footsteps and relay the coordinates w/gps position.

  40. bruce

    You know what they say. If you can see the camera, the camera can see you.

  41. olderwithmoreinsurance

    jeffB is right about the resolution not increasing with aperture. It’s exactly BECAUSE the amateurs have small ‘scopes (and short exposure times) that leads to great photos like this.
    The Fried parameter essentially measures the average size of each blob of air that’s introducing turbulence into an image (yeah, highly simplified). Even at the best sites (like Dome C in Antarctica) it’s about 20 cm. Once your aperture gives much larger than that, your ultimate resolution goes down (baring adaptive optics, as jeffB mentioned).

  42. Mary

    It’s interesting to see this post today. There was just an article in the Globe and Mail entitled
    —-Canadian tracks down secret U.S. space plane —
    One of the fellows connected to our group is the go-to guy for anything regarding satellites. In 2008, he accurately calculated the position of the llost toolbag.
    A lot of people would have just said this was just another satellite passed through the field of view. But, Kevin would be determined to figure out which one it was and not stop until he did. The article can be read at

  43. Mary

    There is a video longside the article. I don’t know if there is any detail visible in it or not. Right now, I am away from home and on dial-up. Boy, do I miss my high speed.

  44. Messier Tidy Upper

    @34. Steeev Says:

    @17 — Under Siege 2: Dark Territory. You were correct in all details except the stolen nuke missiles — that was Under Siege 1.

    Thanks! Much appreciated. Knew the movie (vaguely remembered) but couldn’t recall the title at all. :-)

    @ 35. Marco Langbroek : Thanks too – that makes sense now. :-)

    Although I’m surprised the military doesn’t try and prevent the details being published all the same.

  45. Crowley

    Sigh… someone tell me again why a government is allowed to have secrets from its people, and still be called a legitimate government?

    Because when you become an adult, you realize the world is a festering pit of harsh and depressing realities that must be dealt with, and hoping for unicorns pooting rainbows to save the day is not a winning strategy.

    Even the founding fathers, despite their advocacy for open government, recognized the need for executive secrecy to ensure national security. The tension between the need for secrecy and the desire for openness is a vast and complicated arena of ideas and debate. Your simplistic, binary definition above is ridiculously and shamefully naive.

    The secrecy isn’t about you. Don’t take it personally.

  46. @ #49 Messier Tidy Upper:

    They really can’t. They have no legal means to do so. And many of our observers and analysts aren’t even in the US anyway: so way outside their jurisdiction. But even for US citizens, it is not illegal to publish this material. In fact, the USA has ratified UN treaties that compell them to disclose their spacecraft to the international community.

    Besides, the pragmatists within DoD have learned to life with it and actually value the way this amateur sleuthing reveals what are realistic limits to secrecy. It reminds them that they should not expect that adversaries don’t know where their space assets are. Any ‘rogue state’ can determine satellite orbits using no more than a few people equipped with binoculars, star maps and a stopwatch. Let alone if they have space radar available (e.g. such as China and quite likely N-Korea). Realistic military planning should take this in account.

  47. Astrofiend

    What pisses me off is that they have MULTIPLE satellites up there with roughly the same or better capability than Hubble, and they point the damn things at the ground.

    Yes, I am aware that there would be major design differences meaning that they couldn’t be used as astronomical instruments. But it goes to show how little science is valued in society when funding easily materialises for multiple huge space telescopes dedicated to poking around on Earth looking at various buildings and other trivial goings on while astronomical research can barely raise the funding for one or two, and while congress pisses about, splitting hairs over even modest increases to science spending.

  48. DensityDuck

    Sounds like we need to send Vinnie and Bluto in to have a little chat with this guy.

    “Dat is a very nice telescope dat you have pointing up in the sky dere. You might want to be careful about where you point dat telescope, because it would be a very bad fing if a big rock were to come in troo da window. Lots of rocks flying around out dere, you know, lots of kids playing, you know? So just don’t go pointing dat telescope at track Kay Kay one-six-nine mark two-eight or a rock might come and smash your telescope all to pieces and also hit you onna head.”


    #53: No, Hubble has better resolution than the figures quoted here. You’re right that it would be nice to have three or four Hubble telescopes, but that’s more a question of NASA getting its priorities straight.

  49. I have extracted some images from the associated video:

    If you put a video camera on a telescope and you aim it at a star, the atmospheric turbulence will give images that are (more or less) distorted and spread in random figures (see the animations in If you superimpose the unpredictable shaking effect of the movement of the telescope during manual tracking, you can transform a star into any possible figure (a satellite silhouette, the head of Dark Vador etc.), especially if you take hundreds of images, if you select the ones that fit your needs and if you enlarge them by a factor 2 or 3 (perhaps more) with over-subtle processing (and I do not talk about optical defects such as miscollimation or color Bayer matrix artefacts in the camera sensor) . You can see from these individual images that very different shapes are visible and that the fourth and fifth images could as well correspond to a completely different orientation of the satellite (and consider that these images have not been taken randomly in the video sequence but have been selected!). In addition, the orientation of the satellite in the drawing is pure speculation: we have absolutely no idea of the real orientation of the satellite during the passage. In summary, if we want to link to “bad astronomy” theme, we can say that making a drawing of a satellite in an arbitrary orientation and selecting in the video sequence the images that recall this drawing (or perhaps doing the reverse: selecting arbitrarily distorted images and then making a drawing in accordance), and finally saying that they amazingly correspond…reminds me astrologers who are always right, justifying their theories with pure coincidences carefully chosen! We must remain conscious that an image is NOT reality, it can even be very far from it, especially with an object that spans on only a few pixels. I’m afraid that all we can say is that the satellite has been photographed as a bright point passing in the sky and that the rest is total self-persuasion, including of course the fact that the light could come from the opening of the satellite and not from any other part of it.

  50. kcom

    “,,,and we’re having problems spotting Ossama bin Lauden? With tech this good, we should be able to see what he’s having for lunch.”

    That reminds me of a Simpson’s episode where they are searching for a missing one trillion dollar bill. They believe Mr. Burns has it in his possession. They confirm through high-tech satellite surveillance that it’s not hidden on the roof. Ba-dump-bump.

    For the most part, the government isn’t keeping secrets from its people, it’s keeping secrets from its enemies. (Yes, there are real enemies.) Sharing those secrets with its people would automatically give them to its enemies, what with a free press and all. If you can figure out a way around that conundrum, where a secret can be confined to loyal citizens only, then you might have an argument. Until then, we’re stuck with the real world. But it does emphasize the importance of voting wisely.

  51. Jon Hanford

    55. Thierry Legault Says:

    “We must remain conscious that an image is NOT reality, it can even be very far from it, especially with an object that spans on only a few pixels. I’m afraid that all we can say is that the satellite has been photographed as a bright point passing in the sky and that the rest is total self-persuasion….”

    Point well taken!


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