"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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That looks realy good Bob.  Time to animate. 

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"Steve" <ste### [at] zeroppsuklinuxnet> wrote in message
news:slr### [at] zero-ppslocaldomain...
| That looks realy good Bob.  Time to animate.

Thanks, but no thanks.  Not at 1 hour plus per frame.  Isn't going to
happen.

Bob

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Here's a changed version.  Added the ion tail and smoothed out the dust
tail, even made the coma smaller.  It can't be perfect I don't think, only
better and better (or worse, depending).
Want to credit Constantine Thomas, Kari Kivisalo, and James Hastings-Trew.
I just now got the Earthpng.zip file at Constantine's site which I
previously posted a reply to Christoph Hormann about.  I believe I had been
using the maps from David Seal's site before: http://maps.jpl.nasa.gov/

Bob

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Attachments:
Download 'nearearthcomet2.jpg' (13 KB)

Preview of image 'nearearthcomet2.jpg'

Bob Hughes wrote:
> 
> Here's a changed version.  Added the ion tail and smoothed out the dust
> tail, even made the coma smaller.  It can't be perfect I don't think, only
> better and better (or worse, depending).

better i think, just the tail should somehow thin out in the distance.  

> Want to credit Constantine Thomas, Kari Kivisalo, and James Hastings-Trew.
> I just now got the Earthpng.zip file at Constantine's site which I
> previously posted a reply to Christoph Hormann about.  I believe I had been
> using the maps from David Seal's site before: http://maps.jpl.nasa.gov/
> 

Thanks for the info, i got some similar maps lying around somewhere here but i
never used them in fact and i don't know where i got them from :-) 

Christoph 

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Christoph Hormann <chr### [at] gmxde>
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Bob Hughes wrote in message <3997f68b@news.povray.org>...
>Here's a changed version.  Added the ion tail and smoothed out the dust
>tail, even made the coma smaller.  It can't be perfect I don't think, only
>better and better (or worse, depending).
>Want to credit Constantine Thomas, Kari Kivisalo, and James Hastings-Trew.
>I just now got the Earthpng.zip file at Constantine's site which I
>previously posted a reply to Christoph Hormann about.  I believe I had been
>using the maps from David Seal's site before: http://maps.jpl.nasa.gov/
>


Now that's nice. Tail looks a bit long relative to the size of the
earth.  Maybe move the commet further from the earth.

Gail
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* http://www.rucus.ru.ac.za/~gail/ * Attempting to reboot universe *
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"Gail Shaw" <gsh### [at] monotixcoza> wrote in message
news:39980caa@news.povray.org...
|
| Now that's nice. Tail looks a bit long relative to the size of the
| earth.  Maybe move the comet further from the earth.

Thanks, but it's titled Near Earth Comet   :-)  As I understand it comets
can be quite large objects overall.
I think you and Christoph are right though, it needs some fading out as it
goes toward the far end.  It does at the very end, many times the length you
can see here, but not in a good way.  At the same time I need to get a
curvature for the dust tail too.  Somehow, someway.

Bob

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Looks better, but shouldn't the tail fade out in back?

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Now it looks much better.


Bob Hughes wrote:

> ... As I understand it comets can be quite large objects overall.

  Yes, indeed they can be hundred of times the earth radius.

> ...  At the same time I need to get a curvature for the dust tail too.  

  At the scale of your images I don't think that a curvature would be
noticeable. It also depends on the viewing angle and the vector velocity
of the comet.

Alberto.

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