"Andrew Coppin" <orp### [at] btinternetcom> wrote in message
news:3e14aaa2@news.povray.org...
>
> I'm baaaaaack!!!
>
> (Oh, what's that - no one noticed I was gone? *sigh* Oh well...)

Now that you mention it... yeah, haven't seen you around.

> Anyway, I've been wondering about something... I love lights on Christmas
> trees. And my dad has more sets of lights than you can shake a VERY big
> stick at!! I've been thinking about trying to simulate some with POVRay,
but
> I already know it's not going to be easy. The question is... Why do bright
> lights have an "aura" around them? I mean, you can see a fairy lights from
> quite a distance, considering how tiny they are. If I try and draw them
with
> POVRay they'll be smaller than a single pixel... but in the real world
they
> have a kind of "glare" around them which takes up more space and makes it
> easier to see them from a distance (when they're lit!) Is there some
> physical explaination for this?
>
> Or do I just need to clean my glasses???

I think it has to do with intensity of light. And lens flare; get a little
fogginess on your glasses and you have instant enhancement of size ,even
though dimmer. Eye retinas are much like a CCD (or vice versa) in that the
photons energize the point where the light touches then blooms it outward
from that point. And the lenses of the eyes are never absolutely perfect
either so some distortions occur. Other factors would be the air acting as a
medium to spread the light or any surroundings which reflect the light, as
opposed to being airless and isolated.

When arriving at my sisters house for Christmas just after dark I noticed
her neighbors Christmas lights strung along a white fence and they looked
like lit up colored pingpong balls instead of the usual kind of lights.
Turned out to be the C9 type is all, while my sisters place actually had a
globe-shaped kind strung along the roof and they looked to me like C9's or
C7's until I realized later what they were.

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