Shuttle and station imaged from the ground!

By Phil Plait | March 25, 2009 7:30 am

In honor of the Shuttle Discovery undocking from the ISS today (scheduled for 15:53 Eastern time), I present to you Ralf Vandebergh, who is a very skilled astrophotographer. How skilled? Yeah, this skilled:

ISS imaged from the ground

That shot, taken on March 20, shows the Space Shuttle Discovery docked with the International Space Station… taken from the ground. Vandebergh used a 25 cm telescope with a video camera to get this shot; he tracked the telescope by hand using an ordinary finder ‘scope mounted on the side.

Although the image is fuzzy — the placement of the Shuttle and ISS in the sky wasn’t optimal — the detail is incredible. I found a diagram on the NASA site with a drawing of the Shuttle docked to the ISS. Though it’s not perfect, the angles approximate what Vandebergh got, and you can identify structures:

Click to embiggen.

Pretty cool, eh? You can see the back end of Discovery poking out from under the station (the payload bay doors are open), as well as ISS solar panels and other features, too.

At first glance getting a shot this clear might seem impossible, but in fact the math backs it up. The ISS orbits at 350 km over the surface of the Earth. Let’s say it’s straight overhead, so it’s as close (and therefore as big) as it can get. The wingspan of the ISS is a little over 100 yards. Doing the math*, I get that the station would be about 1 arcminute in size, or about 1/60th of a degree (for comparison, the Moon is 0.5 degrees across). That’s interesting; the resolution of the human eye is about an arcminute! So when it’s directly overhead, people with keen eyesight will just be able to see the station is not just a dot, but has an actual shape.

I didn’t know that. Wow. Through binoculars it’ll be very cool to see. I’ll have to try that.

Anyway, through a decent telescope — and Vandebergh’s 25 cm Newtonian is definitely a good sized ‘scope — you can actually get a good shot of the station. Usually, though, atmospheric turbulence blurs out the picture (which is also why stars twinkle). The trick is to use a video camera: that takes many frames rapidly, hopefully cutting down on the blurring in the same way that a fast exposure of a race car is sharp, while a longer one is blurry.

In fact, you can do even better. The blurring changes not only in time but in space as well. So in a given frame, the starboard solar panels might be sharp, but the port panels blurred. You can take multiple frames from the video and stitch them together, taking only the best parts and deleting the worst. I’ve seen some incredibly detailed images of the Shuttle and ISS taken from the ground; try a Google search and you’ll see plenty.

In fact, astrophotographer Vincent Miu shot this same ISS+Shuttle configuration just this week as well, and last year, the ISS was caught passing Venus in the sky during the day. I imagine anyone with a good ‘scope and a video camera mounted to it can get this sort of thing. That seems incredible to me, but such is they way astronomy has been transformed in the modern era.

Don’t forget, you can see the ISS easily with the naked eye (it can now get brighter than Venus, thanks to the new solar panels). Check out Heavens Above to see when it’s overhead! As soon as it clears up here in Boulder I’ll be out with my own binocs. I trust the math, but it always helps to verify.

* The apparent size of an object depends on how big and how far away it is. The formula is angle = constant x d/D, where d = size, D = distance, and the constant is 206,265 (which is arcseconds per radian, if you’re curious, to convert from natural units to arcseconds). 100 meters/ 350,000 meters x 206265 = about 60 arcseconds.

Tip o’ the spacesuit helmet to Dianne Speakman for the Miu shot.

Image of Station and Shuttle from the ground courtesy Ralf Vandebergh and ALPO, drawing of Shuttle and Station from NASA

CATEGORIZED UNDER: Cool stuff, NASA, Pretty pictures

Comments (69)

  1. cid kilroy

    it really is something to see the space station overhead now that those solar panels brighten it up. i went out last week to look from downtown boston, thinking i’d be lucky if i could see anything, and i was at first disappointed to only see a plane flying overhead…until i realized that it was the ISS!

  2. Nice!

    I image the ISS by hand tracking it through a 10″ scope as well, it’s good fun – a bit of fast paced action as opposed to the regular “point the scope at Saturn, start the imaging software and stand around for a few minutes” routine! I missed the Shuttle+ISS during these recent passes though – ‘twas cloudy. We get another one around April 10th, but the Shuttle will be long gone by then. Oh well, at least the ISS will have some new features to image!

  3. “The trick is to use a video camera: that takes many frames rapidly, hopefully cutting down on the blurring in the same way that a fast exposure of a race car is sharp, while a longer one is blurry.”

    Or you can use a D-SLR with even higher frame rates and burst mode – better resolution, less motion blur, and you don’t even need to worry about seperating the frames in the video into individual images to work with.

  4. Craig

    Wow! For once, I was one up on you. Several years back I saw the ISS with the shuttle attached with my naked eye (thanks to Heavens above I knew when it would pass overhead). I definitely was not a dot, but irregularly shaped, thanks to a visible solar panel array and the shuttle off to one side. Thankfully, on that pass, the shuttle was not obscured by the station. So I was one up on you, but didn’t know it. Now, I can’t even claim that!

  5. Trebuchet

    I saw a really nice pass Saturday evening and got out the binoculars (10×50). It was pretty well impossible for me to hold them steady enough but I could definitely see there was a shape to the ISS, not just a point of light or spherical object. Very nice! I get goosebumps just thinking about the fact there were also ten humans up there.

  6. I got a big smile on my face from looking at that picture. Good find on the NASA sketch, Phil!

  7. Rowan Bulpit

    That isn’t pretty cool, that is FREAKEN AWESOME.

    Yet another reason to invest in a telescope.

    Though I sort of did, but it is 200 year old 😀

  8. Jeff Sonas

    Does anyone know if the magnitude numbers on Heavens Above for the ISS have been updated to reflect its newer brightness due to the new solar panels?

  9. claire

    The telescopes on Haleakela in Maui look at the shuttle regularly. They have the shuttle fly over and show it’s belly so the guys can look and see if there’s any damage, etc. before it re-enters the atmosphere. They can see a 6 inch piece of wire on the shuttle from the ground with their optics. I was amazed.

  10. @Jeff Sonas I can’t be 100% but I observed ISS passes above London in the last 10 days and the numbers seems about right. Also the ISS info page on Heaves Above states that max mag to be -4.6 which just a bit brighter than max mag for Venus (ISS could not have been that bright before)

  11. Peter Eldergill

    I see that the “Canadarm” is labelled on the photo. Yegads, us Canadians have been milking the fact that it’s Canadian made for ….. 25 years?

    (Heh, I say “us” Canadians as if I had something to do with the construction of it :) )


  12. WJM

    I thought I was imagining things, the first couple of times I watched the ISS circle over my planet, when I thought I could make out some shape. Various little niggly bits seemed to stick off. Over time, as they added niggly bits, it seemed to get nigglier.

    Then, other people started mentioning the same thing.

  13. Tim L

    I did much the same thing with my 6″ scope and NexImage webcam. Not quite in the same league though.

  14. Justin

    FYI, it looks like the solar panels are labeled incorrectly. The US segment is the “front” of the station, and since we’re viewing from below, the port solar arrays are on the left side of the image and the starboard solar arrays are on the right.

  15. I went out with my family the other night to see the ISS go over, and I was stunned at how bright it became as it got higher in the sky. Just what magnitude is the ISS now? I know it was something like -2.0 on Heavens Above, but I’m not sure if those figures reflect (hoho, no pun intended) the new solar arrays.

    It was really rewarding to introduce my family to the awesomeness of watching something human-built and human-occupied pass overhead at 320km.

  16. rob

    just read on msnbc that NASA is considering naming the waste disposal unit after Colbert, and not the whole module.

  17. Wolter

    Given the fact that the canada arm is on the same side off the picture (and i think that it is not repositioned afterwards) it is the starboard side. Apparently they fly upside down 😉

  18. Retrogarde

    Incredible stuff, beautiful. Completely new things are to be discovered every day. Impressive.

  19. Makes me want to get out the telescope early this year!

    Aren’t some of the better deepish space images from earth based telescopes taken by using the idea that over time the atmosphere-caused blurriness reveals itself as a source of variation and can thus be factored out?

  20. Justin

    Wolter: Based on the orientation of the orbiter, the ISS isn’t upside-down in that pic. It’s never oriented that way as far as I know.

    There was an EVA on the 21st devoted almost exclusively to work on the port side of the truss, and the arm was repositioned to support the EVA… perhaps in time for this image? There’s also a little arm attached to the side of the Japanese lab on the port side. A little digging shows Mr. Vandebergh has imaged that object before as well.

  21. I wanna be a Space Janitor when I grow up.

  22. QUASAR

    On April 29 this year, ESA will launch the Herschel space observatory and the Planck satellitle!

  23. GREAT post. I’m not even an astronomy enthusiast but could rapidly become one.

  24. Peter K

    How about getting a look at the stuff we supposedly left on the moon.

  25. Gray Gaffer

    Greg, you mean you leave it in its box over winter? But you are missing some of the most spectacular displays! The Great Nebula in Orion. M51 high enough above the haze.

    The technique is called ‘Image Stacking’. It is essentially an application of signal averaging theory: the random fluctuations in successive images contribute 1 / sqroot(2) to the final image, to 1 for the average point, so the non-random ‘signal’ – the image we want to see – grows faster than the random signal – the atmospheric fluctuations – by that ratio. I first encountered the technique in Mass Spectromoter analysis way back when – correlate the sweep of the magnetic field with the detector output and accumulate a running sum for all points. We had a device that showed the signal accumulating on a scope display, with sweep position on X and accumulated (and scaled as needed) count on Y. Very visceral.

    ISS is pretty bright so a video camera is useable for this purpose. Something like M51 – at mag 11 or so – is not, so each exposure needs to be 1 to 2 minutes rather than 1/30 sec. So M51 takes a _lot_ longer in terms of exposure time, standing in the cold monitoring the tracking, etc, to produce a good image than do bright subjects like the ISS, the Moon, the major planets.

    For both ends of this spectrum there are several software choices. I use Keiths Image Stacker, free, for my Mac:

    He has figured out how to automate out a lot of the drudgery, e.g. image alignment, and picking the ‘better’ images.

  26. jmndos

    Why did he not use a still camera like a d300 or a d3

  27. Also a tip of the spacehelmet to the guys who pioneered this kind of imaging, who were taking these shots 13 years ago off the shelf equipment (with mid-90s equipment!) Ron Dantowitz and Mark Kozubal. Got to watch first hand (and help a wee little bit) at the Boston Museum of Science as they coaxed amazing images of the space station and shuttle from ancient computers with analog video equipment, writing their own telescope tracking software.

  28. Oh, a url with some images, past and current:

  29. Great pic and great post. I’ve seen ISS fly by a couple of times. Even with my binoculars, it’s still only a point of light, although brighter than it was last fall. I saw ISS and Discovery this week flyby, same result. huh.

  30. ric

    Can someone tell me when the station will be over or close to coming over Nova Scotia? Thanks

  31. Booker

    May we please have consistent units?

    The image was taken through a 25cm aperture. Check.

    The ISS maintains a nominal altitude of 350km. Check.

    The ISS is a little over 300 yards……BOOOOOOOOOH! 300 Meters, please! This points to a silly issue since the “International Space Station” has to keep two types of tool kits, one of them being (SAE?) in fractional imperial units in order to accommodate the made-in-USA parts. It may be ISS but it ain’t all ISO! There could have been one useful point to having an international space station in that it could have pushed the human space flight portion of the agency to go “metric”, so it would be fully international.

  32. Andy

    The latest version of Photoshop also contains tools for automating the merging of different frames, typically to blur out people on a street for example.

  33. nice pic you got there :) i can’t even take a decent pic of a delta launch

  34. Graham

    A great set of stills and video (linked) of the station before the addition of the panels:

  35. David

    Embiggen? REALLY? Which one of you is the Simpsons Fan?

    Excellent image. It’s nice to see that not only the professionals can get a view of the ISS.

  36. MadScientist

    Very good – and the orientation is as you’d expect unless the ISS gyros went whacky and the station started spinning out of control. It’s good to see some people determined to get shots like these. Hmmm … any observatories out there with a wide(ish) view and some spare observing time that coincides with the ISS overhead and catching the sunlight? I never did think about what could be resolved at ~350km distance (or more if you’re not staring straight up) – perhaps that has something to do with my limited world since I can’t see anything (aside from clouds and atmosphere) at 350km towards the horizon.

  37. MadScientist

    @Peter Eldergill:

    Canada’s put in an awful lot into spaceborne instrumentation in the past 20 years or so. We’re very grateful for Canada’s contributions because folks are really struggling to get their ideas turned into instruments/satellites and getting them to fly, so it’s great that other people are building these things. One of the more recent I recall from Canada is the MOPITT campaign and its instruments. It’s kind of sad that people only seem to remember Canada for the robot arm. Hmm .. MOPITT launched 9 years ago … and I was thinking it was something like 5. I must be getting old.

  38. Papa Surf

    I have an 11″ Schmidt on order. I so want to do this!

  39. russ

    haha click to embiggen…

  40. Erik J

    The shot is amazing, but I must say I like the explanation better a extremely exhilarating, I got more excited when I read the post than when I saw the image.. :-)

  41. nice pic you got there i can’t even take a decent pic of a delta launch

  42. Jesper

    That is VERY cool!

    If the picture would have been a little bit sharper and if the astronauts were doing space walks, I bet it would even be possible to see them out there!

  43. Jon Galbreath

    That’s a perfectly cromulent picture!

  44. Frank Astronomy

    There was a similar picture in the Meade telescope catalog like 5-8 years ago…

  45. Paul VB

    Ralph regularly take amazing picture such as the one shown above (I have seen many of them on a different website). The one that really blew my mind this week was the picture Ralph took that appears to show an astronaut during a space walk!!!

  46. Rich Isaacman

    Actual resolution of the human eye is 2-3 arcmin, depending on conditions. 2 arcmin is considered to be 20-20 vision and is usually achieved with narrow pupil openings, i.e. in daylight conditions. With a wider pupil (i.e. at night), spherical aberration limits visual acuity to about 3 arcmin. So, cool as it might be, you cannot, in fact distinguish the shape of the ISS with the naked eye; it will always appear as a point.

  47. Kevin

    Cool. Now we need to know what else is up there.

  48. John

    Would love to see what sort of picture you could get with 100-1000 frames.

    With some motion compensation you’d effectively be supersampling, which should make for a pretty crisp picture.

  49. mikey

    you looked from downtown boston? why… thats where i am right now! i’ll have to go out and look next time there’s a clear night, though, i would have no idea where to start.

  50. hector

    How can you find the ISS at night?

  51. Tim G

    Here is a photo taken of the ISS allegedly from a 25 inch (64cm) adaptive optics telescope at a Boston area high school.

  52. Your formula is wrong, or at most an approximation. atan(size/2/distance) is correct, but you might need to convert it to arcseconds.

  53. Markus

    The fact that the ISS has a “shape” and isn’t a “dot” anymore is about… oh I don’t know, quite a few years old by now. Where have you been? 😛

    Observing a full ISS pass (with binoculars, preferrably) can be pretty interesting, even though ISS passes are such an everyday sight now that I rarely bother to watch anymore. Early in the pass it will appear slightly reddish or orange, because at that time the sunlight is still shining through the solar panels, which contributes a considerable tint to the otherwise still unfavorable phase angle. By the time it reaches the zenith and the phase angle gets more favorable, it will become bright white (especially with a Shuttle docked to it, but not only then). If the pass includes a shadow entry later on, you might want to try and see how long after shadow entry you can still track the station, considering the sun up there of course doesn’t disappear abruptly and the station also may have some external floodlights on. And considering that, during a full overhead pass, its distance to you varies from a few thousand to just about 350-400 miles, you can even tell how its apparent size grows from a “dot” to a “shape” if you follow it the whole time.

  54. He used a telescope, video camera, and it was still blurry FTA. I would be more impressed with a large lens SLR taking a picture like this.


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