Some week ago we talked about how a lunar eclipse would look as seen from
the Moon (i.e., with the Earth between Sun and Moon, it would be a solar
eclipse from there), and about the possibility of rendering it. Yesterday I
saw in Slashdot a piece of news
(<http://science.slashdot.org/article.pl?sid=09/02/26/198259>) saying that
this has been recorder for the first time by the Kaguya lunar orbiter. The
pictures don't look too impressive for me, I don't see the expected red
tint in the Earth's rim...

-- 
light_source{9+9*x,1}camera{orthographic look_at(1-y)/4angle 30location
9/4-z*4}light_source{-9*z,1}union{box{.9-z.1+x clipped_by{plane{2+y-4*x
0}}}box{z-y-.1.1+z}box{-.1.1+x}box{.1z-.1}pigment{rgb<.8.2,1>}}//Jellby

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Jellby <me### [at] privacynet> wrote:
> Some week ago we talked about how a lunar eclipse would look as seen from
> the Moon (i.e., with the Earth between Sun and Moon, it would be a solar
> eclipse from there), and about the possibility of rendering it. Yesterday I
> saw in Slashdot a piece of news
> (<http://science.slashdot.org/article.pl?sid=09/02/26/198259>) saying that
> this has been recorder for the first time by the Kaguya lunar orbiter. The
> pictures don't look too impressive for me, I don't see the expected red
> tint in the Earth's rim...

Again, it's a poor example because the eclipse was only partial ("penumbral").
It seems to me that the first part of the video, showing a slowly growing ring
of light around the earth, wasn't due to the movement of the celestial bodies,
but just some shutter being opened.

That said, while only the ring was visible the HDR camera may have been
operating at a dynamic range where brightness could be discerned but not color.

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"clipka" <nomail@nomail> wrote:
> That said, while only the ring was visible the HDR camera may have been
> operating at a dynamic range where brightness could be discerned but not
> color.

(Sorry, no HDR camera up there, "only" HD-TV; one more reason to expect the
color fidelity somewhat poor under those lighting conditions.

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Darn, I expected to see a beautiful MCPOV rendering using media and refraction.
Did you post to p.b.i by mistake?

Jellby <me### [at] privacynet> wrote:
> Some week ago we talked about how a lunar eclipse would look as seen from
> the Moon (i.e., with the Earth between Sun and Moon, it would be a solar
> eclipse from there), and about the possibility of rendering it. Yesterday I
> saw in Slashdot a piece of news
> (<http://science.slashdot.org/article.pl?sid=09/02/26/198259>) saying that
> this has been recorder for the first time by the Kaguya lunar orbiter.

Alas, the commenters show the state of science education.  The red ring is not
cause by diffraction.  The ring itself is caused by REfraction, and the color
is caused by Rayleigh scattering.  (Note:  POV-Ray disclaims the ability of
scattering method 4 to produce beautiful colors.)

> The
> pictures don't look too impressive for me, I don't see the expected red
> tint in the Earth's rim...

It's well known that cameras cannot capture the glory of a solar eclipse.  The
problem, at least from Earth-based eclipses, is dynamic range.  The photos that
you've seen of Earth-based eclipses were heavily processed to compensate for the
limited dynamic range of the film or digital media.  (AFAIK, the processing is
generally done by the eyewitness photographers, so they look fairly accurate.)

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Jellby <me### [at] privacynet> wrote:
> Some week ago we talked about how a lunar eclipse would look as seen from
> the Moon (i.e., with the Earth between Sun and Moon, it would be a solar
> eclipse from there), and about the possibility of rendering it. Yesterday I
> saw in Slashdot a piece of news
> (<http://science.slashdot.org/article.pl?sid=09/02/26/198259>) saying that
> this has been recorder for the first time by the Kaguya lunar orbiter. The
> pictures don't look too impressive for me, I don't see the expected red
> tint in the Earth's rim...

Yes, and sadly the video is even worse, specially the overly bright finale.  I
still prefer Kubrick's 1968 offering, thanks.  It's sad that reality never
quite matches are dreams...

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