3D Moon

[ozalba]

Photographs of the Full Moon, 6 months apart - 2013-09-19 & 2014-03-16 - processed to enhance colour differences.

To view in 3D, use cross-eyed method: cross your eyes until you see 3 images, and try to bring the middle one into focus.

Canon 40D, 6-inch reflector, Newtonian focus; 1/125 sec at ISO-100. Images rotated to match libration difference between the two dates; 3D pair assembled in StereoPhoto Maker.

[batema]

That is extremely cool. Do you just put the two photos next to each other. Will it work with any two photos. Well done.

[pluto]

Very nice!
But I see the depth inverted, ie the moon is recessed in the centre?
I don't usually see these cross-eye images that way, I have no problem viewing the ones people generate regularly on unmannedspaceflight.com.

[cometcatcher]

Yeah me too. Looks like looking into a deep bowl. Cool idea though. I never thought to try it myself.

[johnnyt123]

Me too. Moon looks hollowed out.
Like looking into the inside of a bowel.


But it's cool.

[ozalba]

Thanks mate. For 3D stereo to work, you need two images that have been taken from slightly positions, or where the subject has rotated between exposures, so that there is a perspective difference. With the Moon, you have to use the libration effect, but the trick is to get matching phase with the right libration. As the total libration is a mix of E-W and N-S, the variation between any two lunar exposures can be in any direction at all.

For example, with two 1st quarter exposures, you might have to rotate the images so that you get an unusual position angle. The same is true of the Full Moon, of course, but at least it's a round image, and ends up less irritating (IMHO).

[ozalba]

Hmm... sounds like you're viewing it as a parallel pair. It's a similar technique, but you need the images swapped L-R. Try this one below - it's for parallel viewing.

[batema]

I see in the second image the moon looks hollow but in the first one it looks beautiful and round. Not hollow.

[Kunama]

Excellent !!! I see it as a sphere. For those who see it as a bowl, rotate the image 180 degrees then you too will see a ball not a bowl, you can try a handstand or rotate your screen ;)

[ozalba]

Mmm... not sure if you're being serious, or not. Rotating the image won't change the appearance from bowl to ball, just turn it upside-down.

[ozalba]

Well done, that man; I was starting to doubt my own eyes!

[MrB]

Very cool!
By the way, I can go either way (crossed/parallel) at will. That is, I can deliberately make them both appear as concave or convex :thumbsup:

[ozalba]

Thanks Simon. After years of being unable to, I can now freeview parallel, but only if the image centre separation is close to my interocular distance. Cross-eyed: I could do it all day long, but wouldn't want to end up like that well-known silent stereo star Ben "3D" Turpin!

[pelu]

I feel that the depressed center is due a too much time difference between the two images. But it look very well :D

[ozalba]

pelu: whether the appearance is convex or concave depends solely upon which image is on the left, and which on the right (and whether you are using x-eyed or parallel viewing). The amount of libration rotation will affect the strength of the 3D effect. In this case, the total libration difference between the two images was around 12°, which is more than required, so the effect is exaggerated somewhat.

[ozalba]

pelu: having re-read your comment, I realise that you probably meant 6 months was too long a gap. It doesn't matter whether the difference is one month or a hundred years: the only important thing is the difference in libration between the two dates. If the exposures are, say, 25 years apart, but they have exactly the same libration, then there will be no 3D effect at all.

[pluto]

Yeah I think you're right.
This new one doesn't look too good to me but I had another look at the original and changed my viewing style slightly and now it look great!
:)

[pelu]

Yes, I know. I make 3D pairs from my micro minerals images (*). Sound a bit strange, sometime big planet images, sometimes small mineral images :D Because I not able to see the stereo pairs, I have builded a device with four prisms from an old binocular and now I see both 3D posibilities, cross eyes and straight eyes. In my past post I tried to say that the effect was a bit strong, the Moon apperance was near a rugby ball instead a sphere. The aspect of flattened sphere, correct sphere or "rugby balon" is created by the used angle between the two images. Or in my micro images the variation of angle modify how deep seem the "micro landscape". I have found that four degrees is a good value.

In planets, I have tried to do 3D pairs too, but it is easier with Jupiter that with the moon :D : I no must wait some months, only half hour ! :thumbsup:

(*)
https://lh5.googleusercontent.com/-q6h5D3IUko8/Uo6COoc5UUI/AAAAAAAAGh4/30xd1Ybt12s/w1117-h372-no/barita1_3D_X.jpg