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Having uploaded a single image of the Gibbous Moon some time ago, I have finally got around to presenting this 3D pair. These images are scanned from the original prints – themselves made from high contrast negatives – so some of the highlights are a bit blown, but this doesn’t really affect the 3D effect. Other details as per the Gibbous Moon image.
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These images are presented as a pair for viewing with eyes crossed. Stare at them for a few seconds, then cross your eyes until you see 3 images, and try to bring them into focus; if you succeed, the centre image will appear in 3D.

Normal 3D stereophotography requires the taking of pairs of images, with each image taken from a slightly different position; the intention is to replicate the effect of seeing the scene with your 2 eyes, which are separated by 60-65mm. With normal terrestrial photography, this is a fairly simple process, which can be achieved either by mounting 2 cameras side-by-side, or by taking 2 photographs one after the other, moving the camera sideways slightly between exposures.

To achieve any 3D effect with the Moon, the normal approach doesn’t work. The 3D effect is created by parallax – our brain sees slightly different images from each eye, and merges them into one; this allows us to perceive depth in a scene. However, our eyes are optimised for looking at objects about 3 metres away, for good stereo depth, and objects further away are decreasingly perceived in 3D. The Moon, being a quarter of a million miles away, is an extreme example, and you would need to take your stereo pair from one side of the Earth to the other, to achieve the required parallactic separation. This would be possible in theory, given 2 photographers working together, but the normal method is to use the Moon’s own orbital motions to achieve the same result.

As the Moon orbits the Earth, it keeps the same side towards us – mostly. It rotates once on its own axis for each orbit of the Earth; this is known as synchronous rotation. In reality, the elliptical orbit means that the orbital speed is not constant, although its axial rotation is, so that sometimes we are able to see more of the far side than normal, an effect known as libration (in simple terms, the Moon appears to ‘wobble’ slightly from side to side; just to complicate matters, there is also a north-south libration due to the Moon’s tilted axis). We can use this effect to simulate a different viewpoint, allowing the creation of a stereo pair, although the lunar phase needs to be the same, or very close. This Wikipedia article has a simulation of the libration effect.

Jamie Cooper has a similar pair, with a better contrast range and a fuller lunar phase.

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Image Copyright Duncan Waldron © 2009
This image may not be reproduced without permission
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Tags

3d, astronomy, moon, stereo

Comments

  • Soxy Fleming
    Soxy Flemingover 4 years ago

    my brain can’t do whatever it is supposed to do!

  • Sorry Soxy – in trying to multitask, I omitted the explanation of how it works. Will amend forthwith :)

    – Duncan Waldron

  • coops555
    coops555over 4 years ago

    Hey – snap – Nice work Duncan !

  • Max Buchheit
    Max Buchheitover 4 years ago

    Astounding! Have you thought of making an anagyph of this and submitting it to Anaglyph World ? Crossing my eyes works for me, tho.

    Do we have an astronomy group here on RB?

  • Sorry Max, I can’t stand anaglyphs…
    Yes, the Astronomy group.

    – Duncan Waldron

  • Max Buchheit
    Max Buchheitover 4 years ago

    Just out of curiosity , how many seconds elapsed between shots? I’d like to figure out the parallax angle between the two.

  • As I recall, about 2.5 million! 3D shots of the Moon rely on the Moon’s libration effect; I’ll add this to the description.

    – Duncan Waldron

  • coops555
    coops555over 4 years ago

    I see you have put up a more detailed description of stereo photography ( and the complex orbital motions of Moon and earth !) – great stuff, hopefuly people will find it interesting. Maybe we should set up a stereo photography group ?

  • Yeah, I should have done it first off, as I normally do with anything out of the ordinary; apart from anything else, it helps search engnes find the page.

    – Duncan Waldron

  • Max Buchheit
    Max Buchheitover 4 years ago

    Ahhh – now I get it. Thank you for a very good scientific explanation ( my field is remote sensing, but not astronomy).

    Cheers,
    Max

  • Thanks Max; balancing science with readability, as you will know, can be a fine balance :)

    – Duncan Waldron

  • Richard Heath
    Richard Heathover 4 years ago

    Nicely done, I love 3D Stereo images… here are some of my 3D Himalayas

  • Thanks Richard. Yes, I’ve seen your images before; I like the Gauri Sankar one. I really need to do more, and in retrospect, have missed so many good opportunities in the past :-/

    – Duncan Waldron

  • Marloag
    Marloagover 4 years ago

    Brilliant, 3D looks superb and thankyou for explaining the process

  • Many thanks Marloag – you’re welcome. Must try to do more of these (but it’s not a quick process!).

    – Duncan Waldron

  • Matsumoto
    Matsumotoover 4 years ago

    Again, Brilliant!!!

  • KcranmerArt
    KcranmerArtover 4 years ago

    Wow now that is moooootiful!!!

  • :D did you manage to see the 3D effect?

    – Duncan Waldron

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