Yes, media... if you haven't already guessed.
Same old story, try as I might it's always a battle to get such a thing
"right" and this is as far as I've gotten with this one.
The inset is the nucleus region.  Of course it's actually there in the wide
view too  :-) just a bit tiny, the ice chunk being about 50 km wide at most.
The comet is about 4 times more distant than the Moon and the camera angle
(or telephoto zoom?) is at set to 5 in order to get a sufficient scaling to
everything.
I think anyone will notice how the star background is enhanced at the coma,
part of my troubles getting absorption, emission, scattering, density all
together.  Take off your eye glasses if you were them and get way back and
it will look fine, possibly   B-}

P.S.  don't tell me I could get a ready-made comet out of the Galaxy
Include.  I wanted to try on my own anyhow.

Bob
--
omniVerse http://users.aol.com/persistenceofv/all.htm

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Attachments:
Download 'nearearthcomet.jpg' (33 KB)

Preview of image 'nearearthcomet.jpg'

I haven't seen swirls like that in a comet's tail.

By the way, the Moon's surface is much dimmer than that in comparison to
the Earth; 
here are two shots that contain both:
http://antwrp.gsfc.nasa.gov/apod/ap950629.html
http://antwrp.gsfc.nasa.gov/apod/ap980904.html
(from the archive of Astronomy Picture of the Day)

-- 
Anton Sherwood  --  br0### [at] p0b0xcom  --  http://ogre.nu/

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"Bob Hughes" <per### [at] aolcom?subject=PoV-News:> wrote in message
news:3996e1bf@news.povray.org...
> P.S.  don't tell me I could get a ready-made comet out of the Galaxy
> Include.  I wanted to try on my own anyhow.

The comets in the Galaxy Include File don't use media, so you're still
breaking new ground! This looks very good, Bob.

-Dave

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It looks pretty good IMO, i'm just wondering about the turbulence in the tail, i
think gases normally go just strait away from the nucleus.  Maybe the nucleus
could also be a bit brighter in contrast to the tail.  

I much like the clouds of your earth, are they image mapped or made with Povray
?

Christoph

--
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/

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I may be wrong, but I don't believe stars should be visible. Either that or
Earth should be completely washed out. If you can find a photograph that
shows otherwise I'd like to see it. Oh and shouldn't the comet have two
tails (unless its headed straight for the sun)?

Btw, nice render.

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Anton Sherwood wrote:
> 
> I haven't seen swirls like that in a comet's tail.
> 
> By the way, the Moon's surface is much dimmer than that in comparison to
> the Earth;
> here are two shots that contain both:
> http://antwrp.gsfc.nasa.gov/apod/ap950629.html
> http://antwrp.gsfc.nasa.gov/apod/ap980904.html

Hmm....  I think you should work on those textures.  The clouds dont
seem to be very convincing.

And add some AA for more realism.


> (from the archive of Astronomy Picture of the Day)

Oops!

> 
> --
> Anton Sherwood  --  br0### [at] p0b0xcom  --  http://ogre.nu/

-- 
Francois Labreque | Unfortunately, there's no such thing as a snooze
     flabreq      | button on a cat who wants breakfast.
        @         |      - Unattributed quote from rec.humor.funny
  attglobal.net

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"Anton Sherwood" <bro### [at] poboxcom> wrote in message
news:3996EC00.3F38CB4D@pobox.com...
| I haven't seen swirls like that in a comet's tail.

The tail was at first fairly featureless, but I wanted to get a chaotic one
for this.
I was going to put a link to a good example of comets here but didn't find
any really fine photos, Hale-Bopp abounds on the internet apparently, and
most are homegrown pictures, so I gave up.  I believe Comet Halley might be
a good example of a turbulent tail although what I have seen is more
streamer-like.  I should probably do a little more research anyway.  The
coma area might be totally wrong for that matter and should perhaps not be
extending beyond the width of the tail itself at that point.
The real difficulty is getting a unaided eye appearance, all guess-work.

| By the way, the Moon's surface is much dimmer than that in comparison to
| the Earth;

I know, accept to brighten the Earth up so much in relation to the Moon
looked wrong, or would look wrong to the casual viewer anyhow.  I had a
dimmer Moon too and that's the same circumstance.  So I compromised and went
with unreality (easiest!).

Bob

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"Dave Blandston" <gra### [at] earthlinknet> wrote in message
news:3996fb15@news.povray.org...
| "Bob Hughes" <per### [at] aolcom?subject=PoV-News:> wrote in message
| news:3996e1bf@news.povray.org...
| > P.S.  don't tell me I could get a ready-made comet out of the Galaxy
| > Include.  I wanted to try on my own anyhow.
|
| The comets in the Galaxy Include File don't use media, so you're still
| breaking new ground! This looks very good, Bob.

Oh.  Okay then.  Thanks for the moral support btw.

Bob

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"Christoph Hormann" <Chr### [at] schunteretctu-bsde> wrote in
message news:399701EC.DCC26B3C@schunter.etc.tu-bs.de...
|
| It looks pretty good IMO, i'm just wondering about the turbulence in the
tail, i
| think gases normally go just strait away from the nucleus.  Maybe the
nucleus
| could also be a bit brighter in contrast to the tail.

I believe you are right about that.  I was going on the idea of bursts of
activity, almost like on/off gases.  Just not so sure yet if that is
correct.  Will have to do more looking around at actual photos.

| I much like the clouds of your earth, are they image mapped or made with
Povray ?

Cloud image mapped onto a slightly larger sphere than the Earth surface one.
Not a greatly detailed one but it's better than trying to make that at the
same time as dealing with the comet creation.
For planetary maps have a look at this site:
http://www.lancs.ac.uk/postgrad/thomasc1/render/render.htm

Bob

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"Jetlag" <bga### [at] microsoftcom> wrote in message
news:39975d63$1@news.povray.org...
| I may be wrong, but I don't believe stars should be visible. Either that
or
| Earth should be completely washed out. If you can find a photograph that
| shows otherwise I'd like to see it. Oh and shouldn't the comet have two
| tails (unless its headed straight for the sun)?

Hi there, glad you liked it despite the shortcomings  :-)
Yes, I know, two tails.  One for dust, other for plasma, I think is how it
goes.  But I was having a tough enough time merging together the inner and
outer coma and tail as it was.  Some comets like Hale-Bopp had a great
separation of the two.  Halley's seems to not have had any from what I saw
while looking at a few photos.
Not really going for a photographic look to begin with actually.  That would
make for a oversaturated coma and very bright tail.  Along with the washed
out Earth, as you said.  Think unreal realism  :-)  Well, whatever...
Maybe I can get it looking better later, maybe not.  This is not the sort of
thing I find easy to try since it's not totally fantasy and not completely
humanly observable.

Bob

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