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Jellby <me### [at] privacy net> wrote:
> Has anyone seen a picture (ideally a photograph) of how a lunar eclipse
> looks from the Moon (from there, it would be a solar eclipse). In total
> lunar eclipses the Moon usually gets a reddish tint, apparently from
> sunset-like light all around the Earth (as seen from the Moon), I'd like to
> see this.
I doubt whether a photograph of such an event exists:
- To date, manned missions to the moon (i.e. Apollo 8 and 10-17) have never been
carried out during lunar eclipses, and to all my knowledge, traversal of earth
shadow during Apollo missions has only occurred in earth orbit; other manned
missions have never even come close to similar distances from earth.
- To date, only very few sattelites have carried photographic film cameras
onboard, and those that did probably never left earth orbit (problem of
retrieval of the exposed film material).
- Satellites leaving earth orbit often had much farther destinations, requiring
trajectories optimized for efficiency, with not much room for the beauty of
lunar eclipses.
- Although some satellites have been deliberately "parked" on the "shadow" side
of earth at the so-called "Lagrangian Point 2" (one of 5 points at which
satellitest can be kept at a stable position relative to earth and sun with
very little effort), this point is at five times the distance of the moon. As
it happens, this is about the distance at which the sun starts to appear bigger
than the earth, probably spoiling the whole effect.
- As for any satellites that might have more or less "accidentally" happened to
cross the earth's shadow at a fitting distance, pointing any optical cameras
towards earth (and sun) during that time would have posed the danger of failing
to turn them away again in time, putting the equipment at high risk of damage.
So probably the only thing we can do to enjoy the beauty of such a sight is to
do what we're best at anyway: Fire up our imagination and inventiveness, and
then fire up POV-Ray.
(BTW, If done right, I guess this could make a tremendous scene for that
planetarium showreel project...)
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"Jellby" <me### [at] privacynet> schreef in bericht
news:c5e### [at] badulaqueunexes...
> Has anyone seen a picture (ideally a photograph) of how a lunar eclipse
> looks from the Moon (from there, it would be a solar eclipse). In total
> lunar eclipses the Moon usually gets a reddish tint, apparently from
> sunset-like light all around the Earth (as seen from the Moon), I'd like
> to
> see this.
>
There is a subject for an awesome POV-Ray scene.... As said already by
others, I don't think there are any photographs available.
Who takes up the gauntlet? :-)
Thomas
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"Thomas de Groot" <tDOTdegroot@interDOTnlANOTHERDOTnet> wrote:
> There is a subject for an awesome POV-Ray scene.... As said already by
> others, I don't think there are any photographs available.
>
> Who takes up the gauntlet? :-)
I would if I had the time these days: That earth model I used in the "Not!" shot
still needs a bit of polish anyway, improving the atmosphere colors,
realistically modelling the IOR gradient and all.
My fingers are itching like hell to jump on this, actually. If I wasn't working
on radiosity code these days, that's what I'd spend the nights on: Lunar
eclipse as seen from the moon... astronauts and all included! Digging up that
half-finished Apollo spacesuit model again, polishing up the finished Apollo
Lunar Module... ah, what better setting to revive the heroes of my childhood!
Vade! Tempt me not, if you want the radiosity code to come to completion any
time soon...!
(... Man, you're lucky that realistic lunar scenes *need* radiosity, with all
that indirect light reflecting from the moon's surface...)
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"clipka" <nomail@nomail> schreef in bericht
news:web.496b1d304590b7f02c9ab000@news.povray.org...
> "Thomas de Groot" <tDOTdegroot@interDOTnlANOTHERDOTnet> wrote:
>> Who takes up the gauntlet? :-)
>
> I would if I had the time these days: That earth model I used in the
> "Not!" shot
> still needs a bit of polish anyway, improving the atmosphere colors,
> realistically modelling the IOR gradient and all.
>
> My fingers are itching like hell to jump on this, actually. If I wasn't
> working
> on radiosity code these days, that's what I'd spend the nights on: Lunar
> eclipse as seen from the moon... astronauts and all included! Digging up
> that
> half-finished Apollo spacesuit model again, polishing up the finished
> Apollo
> Lunar Module... ah, what better setting to revive the heroes of my
> childhood!
>
>
> Vade! Tempt me not, if you want the radiosity code to come to completion
> any
> time soon...!
>
> (... Man, you're lucky that realistic lunar scenes *need* radiosity, with
> all
> that indirect light reflecting from the moon's surface...)
>
[Satanas retreats a few steps, grinning]
Well, there is an incentive for you... :-)
Thomas
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"Thomas de Groot" <tDOTdegroot@interDOTnlANOTHERDOTnet> wrote in message
news:496b0649$1@news.povray.org...
>
> "Jellby" <me### [at] privacynet> schreef in bericht
> news:c5e### [at] badulaqueunexes...
>> Has anyone seen a picture (ideally a photograph) of how a lunar eclipse
>> looks from the Moon (from there, it would be a solar eclipse). In total
>> lunar eclipses the Moon usually gets a reddish tint, apparently from
>> sunset-like light all around the Earth (as seen from the Moon), I'd like to
>> see this.
>>
>
> There is a subject for an awesome POV-Ray scene.... As said already by others,
> I don't think there are any photographs available.
>
Actually, Surveyor II took a picture of a solar eclipse from the moon.
Images were retrieved by Apollo 12 crew who also snapped a nice picture
in space (not on the moon's surface).
There is a page with good math data at
http://star-www.st-and.ac.uk/~awc/eclipse.html
(part 2).
Theory says the earth will be quite a sight as earthshine will center an
image of a planet surrounded by all the world's sunsets at the same time.
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"pan" <pan### [at] syixcom> wrote:
> Actually, Surveyor II took a picture of a solar eclipse from the moon.
> Images were retrieved by Apollo 12 crew who also snapped a nice picture
> in space (not on the moon's surface).
Hum - I forgot about the Surveyor probe indeed (it was Surveyor 3 though, not
2). That would have been a chance to get some nice shots of a "lunar solar
eclipse".
Unfortunately, you are a bit misinformed: Apollo 12 did not retrieve any
photographic images from the probe, neither did the probe carry any
photographic camera in the first place. It had been sitting around on lunar
soil for three years already, and when it had been built, probably nobody had
expected a manned mission to land anywhere close. So all the Apollo 12 crew
took home was some parts of the probe, probably to examine some problems
experienced (including the TV camera) and learn some lessons from it.
The eclipse shot from Surveyor 3 is actually a very bad black-and-white shot,
that had been transmitted years earlier already, and - as the beautiful Apollo
12 shot indicates - does the event no justice whatsoever.
The Apollo 12 shot, on the other hand, was taken comparatively close to earth,
so it, too, can only hint at how it might look in reality from the moon.
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[sorry! 1st emailed instead of reply here. Out of practice using
newsgroups.]
I had made a few attempts to show the solar system or parts of it in POV-Ray
over the years. As I read others saying here, scale modeling and getting
the view right can be trouble... for me anyhow.
When I first read your post last week I was going to look for what I might
have done before but decided to start fresh again. Idea this time being to
create an "orrery" of various scales fit together into one scene file. Not
sure I succeeded but I'm posting it anyway at povray.binaries.scene-files,
less the image maps since you could easily replace them with textures or
images found online. Low resolutions okay and faster to render, I down-sized
mine to 720X360 from hi-res ones I already had.
(example: earth-map.jpg, jupiter-map.jpg)
While going to post this I saw David Buck's fictional scene at p.b.s-f. I
realize now my try at it might seem confusing at first, too. heh-heh-heh.
:^) Since the topic of atmosphere during eclipses was brought up as I
returned to read here while refining the orrery I tried adding that without
success. Poorly done so ignoring that part might be best-- unless someone
wants to fix it.
I can't be certain I got all the elements of the orbits right, I fumbled
with the sizes and angles until it looked like the animations kept the
correct orbital inclinations; and all along writing the file out in such a
way that made sense to me yet not sure it will to everyone else. No doubt
better methods or implementations exist than what I chose.
Again, it's being posted at povray.binaries.scene-files, under the name
"solar system orrery ver1", since the text line-wrap would be a disaster if
posted here.
Bob
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Among other things, clipka saw fit to write:
> My fingers are itching like hell to jump on this, actually. If I wasn't
> working on radiosity code these days, that's what I'd spend the nights on:
> Lunar eclipse as seen from the moon... astronauts and all included!
> Digging up that half-finished Apollo spacesuit model again, polishing up
> the finished Apollo Lunar Module... ah, what better setting to revive the
> heroes of my childhood!
I've been wondering about this lunar-eclipse-from-the-moon image for some
years, so I'm looking forward to whatever you can get :)
P.S. I'm also glad this raised some interest. Another thing I've been
thinking about for years is how cool a "bird flight simulator" would be.
Think of it, instead of controlling a plane you'd control a bird, the wing
flapping frequency, the tail... there would be different kinds of birds and
different "missions" (a migration with a duck, capturing a pigeon with a
hawk...) And the scenery could be anything from a city full of buildings to
a garden with flowers (for a hummingbird)... and rendered with POV-Ray :D
--
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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Alain <ele### [at] netscapenet> wrote:
> >
> It's 20 lightyears away from HERE.
>
> A planet orbiting it's sun at a 20 lightyears radius would need to have an
> extra-galactic sun, or get snatched away by nearby stars. Such a planet would
> also be frozen solid, with, maybe, sone seas of liguid hydrogen and helium. It's
> "year" would last several 100's of millenias.
>
Just for fun, I made the calculation for a star with the same mass as the sun:
following Kepler's thrid law the planet would orbit the star once every 1.4
billion years at a speed of 26 m/s (95 km/h), which IMO is still surprisingly
fast, about 1/1000 of the speed of earth.
Like you said it would have to be a solitary star, but that shouldn't be a
problem, there's a lot of space out there. Pun intended :-)
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stevenvh nous illumina en ce 2009-02-05 08:33 -->
> Alain <ele### [at] netscapenet> wrote:
>> It's 20 lightyears away from HERE.
>>
>> A planet orbiting it's sun at a 20 lightyears radius would need to have an
>> extra-galactic sun, or get snatched away by nearby stars. Such a planet would
>> also be frozen solid, with, maybe, sone seas of liguid hydrogen and helium. It's
>> "year" would last several 100's of millenias.
>>
>
> Just for fun, I made the calculation for a star with the same mass as the sun:
> following Kepler's thrid law the planet would orbit the star once every 1.4
> billion years at a speed of 26 m/s (95 km/h), which IMO is still surprisingly
> fast, about 1/1000 of the speed of earth.
> Like you said it would have to be a solitary star, but that shouldn't be a
> problem, there's a lot of space out there. Pun intended :-)
>
>
>
As I sayd, 100's of millenias. 1.4 billions years is 1400 millenias.
You said "lots of space" out there... You bet! Over all, the galaxys "use" less
than 1% of the "space".
--
Alain
-------------------------------------------------
Agnostic: Shit might have happened; then again, maybe not.
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