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Has anyone tried anything like Orbiter (
http://orbit.medphys.ucl.ac.uk/orbit.html ) in POV-Ray? I would like to be
able to do a flyby of the solar system with warp-speed between planets. Tips
on how to determine the postition of any given planet at any given date
would also be very helpful.
tnx
--
-Nekar Xenos-
----------------------------------------
"The truth is out there..."
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"Nekar Xenos" <go_### [at] yahoo com> wrote:
> Tips on how to determine the postition of any given planet at any given date
> would also be very helpful.
>
Nekar,
My recent post to povray.general provides a method of calculating the
position of the Sun, Earth and Moon so that Solar (and Lunar) eclipses can
be modelled.
The method could be extended to include all the planets.
The idea of my scene file 'eclipse.pov' (downloadable from
http://www.pavium.info/Eclipse/) is to calculate the positions of the Sun,
Earth and Moon at a particular date and time, and then render a picture
showing the shadow of the Moon on the Earth, or vice versa.
You may not need that much accuracy.
I based the code on algorithms I found in books, mainly 'Astronomical
Algorithms' by Jean Meeus, Willman-Bell, 1991.
There are many other books which take a less rigorous approach. Jean Meeus
did an earlier book called 'Astronomical Formulae for Calculators'. Peter
Duffet-Smith did a couple of books called something like 'Astronomy With
Your Calculator'
I don't know if there are any more recent books.
Good luck with your solar system project.
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"pavium" <jrc### [at] tpgcomau> wrote in message
news:web.44175355669cd8c78398f4b40@news.povray.org...
> "Nekar Xenos" <go_### [at] yahoocom> wrote:
>> Tips on how to determine the postition of any given planet at any given
>> date
>> would also be very helpful.
>
> My recent post to povray.general provides a method of calculating the
> position of the Sun, Earth and Moon so that Solar (and Lunar) eclipses can
> be modelled.
>
> The method could be extended to include all the planets.
>
> The idea of my scene file 'eclipse.pov' (downloadable from
> http://www.pavium.info/Eclipse/) is to calculate the positions of the Sun,
> Earth and Moon at a particular date and time, and then render a picture
> showing the shadow of the Moon on the Earth, or vice versa.
I remember now that there was a planetarium for POV some years ago, so I
went looking for it. The resources link at povray.org shows it there but its
link is broken. I couldn't locate it in a search of the internet or my
computer, although I think I must have it someplace. Might have been
perfect. If I do find it I'll post back here.
Bob
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"Bob Hughes" <omniverse@charter%net> wrote in message
news:441793d8$1@news.povray.org...
> I think I must have it someplace. Might have been perfect. If I do find it
> I'll post back here.
Didn't take me long to find it wa-a-ay in the back of my *other* computer.
It's by Marius Van Der Spek, from 1998, a DOS utility called povplan.exe. No
idea how it works but there's plenty of documentation and other files along
with it.
If anyone wants it send e-mail to me after changing the % in my address, at
least POV in the subject line so I don't delete.
Actually, I'm wondering if it might be okay to upload this to my web site or
someplace else. Then again, it wasn't at the POV Objects Collection site
where another broken link was found so maybe it was never intended to be
hosted anyplace.
Bob
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"Hughes, B." <omn### [at] charternet> wrote in message
news:441799b2$1@news.povray.org...
> "Bob Hughes" <omniverse@charter%net> wrote in message
> news:441793d8$1@news.povray.org...
>> I think I must have it someplace. Might have been perfect. If I do find
>> it I'll post back here.
>
> Didn't take me long to find it wa-a-ay in the back of my *other* computer.
>
> It's by Marius Van Der Spek, from 1998, a DOS utility called povplan.exe.
> No idea how it works but there's plenty of documentation and other files
> along with it.
Thanks Bob, that would be helpful.
But I would alos like to be able to do it completely in POV-Ray - then I
could have more control over it.
--
-Nekar Xenos-
----------------------------------------
"The truth is out there..."
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Apologies to everyone trying to go to my FTP site (if you see my other
recent replies here). I can get there myself and I did make sure to enable
anonymous ftp, too, however I still see there's trouble in getting to the
file directly. Please try:
ftp://3digitaleyes.com/public_ftp/
and if you get into there you should see pplan009.zip and could download it
from there. Not sure what's wrong with my new host's FTP that prevents the
direct download. Not the best time to be learning it, I'm sorry if any of
you have trouble.
I cancelled my previous two replies so here again is what was said in my
first, minus the URL, even if that still shows up for you.
_________________________________
For anyone reading/searching these groups, POV Planetarium 0.9 by Marius van
der Spek can be downloaded from my site:
That will be there temporarily, or until I get word to remove it or decide
it has served the purpose of helping others get it for now since only broken
links to the original file could be found by me, with no sign of any updated
version either. I just won't be linking to it from anyplace (except right
here) and ask that no one else create web page links to it, please. Unless
maybe the POV-Team or povray.org webmaster deems it okay to change their
Resources link to this one, in which case I'd place it in a more permanent
POV-specific folder there, first. ;)
I've also added a notice to the readme.txt to explain the archive I had was
not a completely original zip yet should be the same aside from the
povplan.exe being run with a date and time which created corresponding
files.
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Sought out answers about my web host's FTP and finally found a way for
people to get to the folder containing the file. Still impossible to access
it directly, unless maybe you use some FTP program maybe (which I don't) but
somehow I doubt that now.
This should get you there anyhow, so ignore the previous URL's please!
ftp://anonymous@3digitaleyes.com/public_ftp/povutility/
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In article <web.44175355669cd8c78398f4b40@news.povray.org>,
"pavium" <jrc### [at] tpgcomau> wrote:
> I based the code on algorithms I found in books, mainly 'Astronomical
> Algorithms' by Jean Meeus, Willman-Bell, 1991.
great book !
recommanded for this.
--
klp
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"pavium" <jrc### [at] tpgcomau> wrote in message
news:web.44175355669cd8c78398f4b40@news.povray.org...
> Nekar,
>
> My recent post to povray.general provides a method of calculating the
> position of the Sun, Earth and Moon so that Solar (and Lunar) eclipses can
> be modelled.
>
> The method could be extended to include all the planets.
>
> The idea of my scene file 'eclipse.pov' (downloadable from
> http://www.pavium.info/Eclipse/) is to calculate the positions of the Sun,
> Earth and Moon at a particular date and time, and then render a picture
> showing the shadow of the Moon on the Earth, or vice versa.
>
> You may not need that much accuracy.
>
Pavium,
I had already downloaded it at the time of posting my request. When I opened
the file and saw the diagram with
(Sun)----(Moon)----(Sun0)----(Moon0)----(Earth)
I realised I am going to have to disect this file. Then when I saw you have
the sun and moon rotating around the earth, and knowing this is only to find
eclipses, I figured I would have to do some "reverse engineering" as well.
This could work but I need to know which Sun and Moon are correct?
Thanks.
--
-Nekar Xenos-
----------------------------------------
"The truth is out there..."
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> When I opened
> the file and saw the diagram with
> (Sun)----(Moon)----(Sun0)----(Moon0)----(Earth)
> I realised I am going to have to disect this file. Then when I saw you have
> the sun and moon rotating around the earth, and knowing this is only to find
> eclipses, I figured I would have to do some "reverse engineering" as well.
>
> This could work but I need to know which Sun and Moon are correct?
>
> Thanks.
>
>
> --
> -Nekar Xenos-
I started by trying to create a realistic scene with the Sun, Moon and
Earth.
The Sun was originally an extended light source.
This gave me the effect seen in the simple animation on the home page
http://www.pavium.info/Eclipse
The shadow was fuzzy (as it should be) but this made it difficult to see the
path of totality.
I wanted to see if I could reproduce the maps included in NASA's literature,
so I came up with an artificial solution.
I made the Sun a point source of light. This gave the Moon's shadow a sharp
edge. Then I added a second sun (Sun0) between the Moon and Earth and a
second TINY moon (Moon0) between Sun0 and the Earth. Sun0 dimmed the shadow
cast by the Moon, but Moon0 added a small shadow which represented totality
in the centre of the shadow made by the true Sun.
Here's a diagram. (Light travels left to right)
True True
(Sun)----(Moon)----(Sun0)----(Moon0)----(Earth)
| | No Shadow
| | | Shadow of Moon = penumbra
| | | Shadow of Moon = penumbra
| | | | Shadow of Moon0 = umbra
| | | Shadow of Moon = penumbra
| | | Shadow of Moon = penumbra
| | No Shadow
If you just want simple, natural, shadows you should get rid of Sun0 and
Moon0, and change the definition of Sun to give you a light emitting sphere
of radius 6.96E6 kilometres.
Along the way, I decided that a point-source Sun required a double-size Moon
to give a 'penumbra' of the right size. This was really a trial and error
thing, I have no proof, it looked right - but you should look for this and
make sure the Moon is the correct size.
Actually, I'd forgotten about the 'geocentric co-ordinates' and the
impression it gives that everything rotates around the Earth.
It's just convenient mathematically to move the origin of the co-ordinates
to the Earth (especiallly since that's where the camera is pointing). I get
the impression astronomers switch co-ordinates systems at the drop of a hat.
'Astronomical Algorithms' provide routines to calculate the orbits of the
planets in geocentric co-ordinates, and it can be a lot simpler than the
calculation of the Moon's position.
Regards,
pavium
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