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Message no. 1
From: shadowrn@*********.com (Bryan Pow)
Subject: ShadowRN digest, Vol 1 #1860 - 10 msgs
Date: Wed Apr 17 17:55:00 2002
> > Wrong. Check any military website or ask someone who knows about it
> > and you will discover that
> > "Thermal energy is transmitted as infrared radiation" I use the term
> > radiation as light is a form of radiation (i believe its called the
> > "electromagnetic spectrum') as are microwaves. Heat takes many
> > seconds to pass
> > across a room at heat (which is excited particles transfering energy
> > to neighbouring particles) but instantly as thermal energy, ie IR
> > radiation. If thermographic goggles relied only on actual heat
> > rather than thermal
> > energy (which is transmitted as IR) then you would get a picture of
> > the air in front of you. Even if you could get a picture of a tank
> > it would take minutes for it to reach you, making it useless.
>
> Could you restate that in terms of propagating photons? You lost me.
> --Anders
>

A quick search turned up these two sights

http://www.catamountcorp.com/irbasics.html

http://www.darien.lib.ct.us/nhfd/thermal.htm

Basically, all objects emmit light. They emmit light over a spectrum. The
hotter the object the larger the spectrum, and the more light they emmit. This
is why hot metal glows, because its heat has increased the range of its
spectrum to overlap the visible spectrum. The peak of the spectrum for a human
body, and anything within a few dozen Kelvin, is 10 to the 4 nanometres, which
is the wavelength of infrared light. The peak of the suns spectrum happens to
be about that of the visible spectrum, but covers a range from about 60nm to 10
to the 7 nm. Note that even though a hot objects peak may not be at the
wavelength of infrared, it is still emmiting it, and more so than a colder
object. Thermographic vision takes advantage of this by capturing infrared
light and imaging it on a screen.

--
Ein scharfes Schwert schneidet sehr, eine scharfe Zunge noch viel mehr.
The tongue is sharper than any sword.
Message no. 2
From: shadowrn@*********.com (Anders Swenson)
Subject: ShadowRN digest, Vol 1 #1860 - 10 msgs
Date: Wed Apr 17 18:25:01 2002
> > Could you restate that in terms of propagating photons? You lost
> me.
> > --Anders
> >
>
> A quick search turned up these two sights>
> http://www.catamountcorp.com/irbasics.html>;
> http://www.darien.lib.ct.us/nhfd/thermal.htm
> > Basically, all objects emmit light. They emmit light over a
spectrum.> The> hotter the object the larger the spectrum, and the
more light they emmit. This is why hot metal glows, because its heat
has increased the range of its spectrum to overlap the visible
spectrum. The peak of the spectrum for a human body, and anything
within a few dozen Kelvin, is 10 to the 4 nanometres, which is the
wavelength of infrared light. The peak of the suns spectrum happens to
be about that of the visible spectrum, but covers a range from about
60nm to 10 to the 7 nm. Note that even though a hot objects peak may
not be at the wavelength of infrared, it is still emmiting it, and
more so than a colder object. Thermographic vision takes advantage of
this by capturing infrared light and imaging it on a screen.
>
OK, you have wavelength covered. Now, what about illumination and
signal strength? Are living human bodies bright enough in the IR to be
picked up by radiated energy alone, using military grade sensors? What
about Metahuman IR eyes? Does a person radiate as brightly as a
military IR searchlight? By what factor less?

--Anders
Message no. 3
From: shadowrn@*********.com (Bryan Pow)
Subject: ShadowRN digest, Vol 1 #1860 - 10 msgs
Date: Wed Apr 17 18:35:01 2002
>OK, you have wavelength covered. Now, what about illumination and
> signal strength? Are living human bodies bright enough in the IR to be
> picked up by radiated energy alone, using military grade sensors? What
> about Metahuman IR eyes? Does a person radiate as brightly as a
> military IR searchlight? By what factor less?

Yes, humans are bright enough to pick up by radiated enerry alone. This is
done by the same light enhancement used in normal Night Vision sights. In
fact the most useful component of thermographic vision for the military is
the the fact everything can be seen with it. As for a military IR
searchligh, these were only used before amplification technology became good
enough. And no, a person wouldn't be as bright as a search light, for the
same reason that my monitor isn't as bright as a normal search light.




When Angels cry "Whence comes your fear?"
I shall reply "I find it here"


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Message no. 4
From: shadowrn@*********.com (Anders Swenson)
Subject: ShadowRN digest, Vol 1 #1860 - 10 msgs
Date: Wed Apr 17 19:00:01 2002
On Thu, 18 Apr 2002 10:33:32 +1200
"Bryan Pow" <bryan_pow@*******.com> wrote:
> >OK, you have wavelength covered. Now, what about illumination and
> > signal strength? Are living human bodies bright enough in the IR to
> be
> > picked up by radiated energy alone, using military grade sensors?
> What
> > about Metahuman IR eyes? Does a person radiate as brightly as a
> > military IR searchlight? By what factor less?
>
> Yes, humans are bright enough to pick up by radiated enerry alone.
> This is done by the same light enhancement used in normal Night
> Vision sights. In fact the most useful component of thermographic
> vision for the military is the the fact everything can be seen with
> it. As for a military IR searchligh, these were only used before
> amplification technology became good enough. And no, a person
> wouldn't be as bright as a search light, for the same reason that my
> monitor isn't as bright as a normal search light.

Now, the killer question. Is the energy emitted by a (meta)human
equivalent to the energy emitted or reflected by the typical object
bright enough to be seenby the naked eye? Can my Orc see you in the
dark, in other words?

--Anders
Message no. 5
From: shadowrn@*********.com (Bryan Pow)
Subject: ShadowRN digest, Vol 1 #1860 - 10 msgs
Date: Thu Apr 18 23:10:01 2002
>Now, the killer question. Is the energy emitted by a (meta)human
> equivalent to the energy emitted or reflected by the typical object
> bright enough to be seenby the naked eye? Can my Orc see you in the
> dark, in other words?

Yes, the orc should deffinitely be able to see me in the dark, as readily
with Thermographic as during the day. The sites I looked at concerning
military thermographic said that one of the main benefits of thermographic
is the fact that ambient light has little to no effect. There is little
difference between the way things look at night and the way they look during
the day, which makes them perfect for operations where you will be going in
and out of dark places during the day. ie, you won't be blinded because the
sun is up.



When Angels cry "Whence comes your fear?"
I shall reply "I find it here"


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Message no. 6
From: shadowrn@*********.com (Anders Swenson)
Subject: ShadowRN digest, Vol 1 #1860 - 10 msgs
Date: Thu Apr 18 23:50:01 2002
>
> Yes, the orc should deffinitely be able to see me in the dark, as readily
> with Thermographic as during the day.>
>
>
OK, then, good. We Glow in the Dark!

--Anders
Message no. 7
From: shadowrn@*********.com (Bryan Pow)
Subject: ShadowRN digest, Vol 1 #1860 - 10 msgs
Date: Fri Apr 19 00:20:01 2002
> > Yes, the orc should deffinitely be able to see me in the dark, as
>readily
> > with Thermographic as during the day.>
> >
> >
>OK, then, good. We Glow in the Dark!

Correction: We glow 24/7, day and night.


--
When Angels cry "Whence comes your fear?"
I shall reply "I find it here"


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Further Reading

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