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Posted by: Kurukami Oct 30 2003, 05:24 PM

There's a particular character in a campaign I'm in, a troll mage with a security helmet decked out with all the nifty toys (among them magnification). Recently he got sniped at from behind/the side (out of his initial field of vision). The player then turned and asked whether or not he could spot where the shot came from, given that he had thermo and visual magnification to spot the heat from the muzzle plume.

Keep in mind this sniper was something like 800 meters away, and this was in a city environment with tons of other visual clutter.

So here's the question: would you allow the character in question to quickly spot the precise spot where the shot came from and, on his next action, stunbolt the sniper. Said sniper would presumably would be under cover/concealment, and nearly a klick away.

Posted by: Tanka Oct 30 2003, 05:26 PM

If in a city, no. Too much other thermal to make sense out of where a thermal muzzle flare was going on. Especially that far away.

If in the countryside, possibly, depending on distance and what else was around that might interfere.

Posted by: TinkerGnome Oct 30 2003, 05:30 PM

At that distance, with the time it takes to turn around, probably not. By the time he turned the hot spot was probably faded significantly. If he were looking right at general direction of a silenced shot, however, he would see the heat as clearly as most people see muzzle flare. Prevalent air temperature is also important. There's a big difference in appearance between a shot at 0C and one at 30C (the difference between flare at night and day).

Posted by: Kagetenshi Oct 30 2003, 05:45 PM

Nope, not unless the sniper was using a magic superheated gun.

~J

Posted by: Siege Oct 30 2003, 05:55 PM

Keep in mind they work on entirely different principles:

Thermo picks up heat generated from a given source. Vision mag can't amplify the heat source; it amplifies reflected em radiation (light). If thermo was working off of IR, that would be another story.

The bigger, more advanced the thermo sensor is, the further the distance and the greater the sensitivity.

Now, detecting muzzle flashes with lowlight and vision mag works perfectly (in dark or low-light conditions).

-Siege

Posted by: Tanka Oct 30 2003, 05:57 PM

Just make sure you have the Flare Compensation or you'll have a grand ol' time of seeing the guy to smack him.

Posted by: Shadow Oct 30 2003, 06:42 PM

I am pretty sure thermo doesn't work from that far away. It doesn't say it in the books but it makes sense. magnifying light from a distance is easy, but how do you magnify the thermographic signature of something as insignificant as a cat from 800 meters away. I say a cat because a muzzle and the body temp of a cat are about the same. You can hold the muzzle of a riffle in your hand when you fire it, you just get warm. Now if you are on auto fire, that is when it get's hot.

My rule: Nay, and the character sounds like a munchkin to boot.

Posted by: Cray74 Oct 30 2003, 07:45 PM

Posted by: Shadow Oct 30 2003, 07:58 PM

Your confusing real life with Shadworun again, tsk tsk. In SR Thermal is just that heat. The glasses pick off heat emited by a given object, not the Infared Radiation.

Posted by: Siege Oct 30 2003, 08:00 PM

Really? I was under the impression that SR thermo worked off sensing heat, not IR radiation.

Then yes, magnification should certainly work with thermo.

Now, here's the quick question: would thermo pick up residual body heat from, say, someone sitting in a chair?

-Siege

Posted by: Game2BHappy Oct 30 2003, 08:01 PM

If he's willing to spend a simple action to "Observe in Detail", give him a perception check to notice the guy. You, as the GM, take into account any modifiers from thermo, cover, camo, how much area the character has to search, etc. and give him the roll.

For example, character one gets shot by a sniper. Character 1 gets an intelligence check (as a Free Action) to figure out the shot came from somewhere down Main Street. He then spends a simple action to Observe in Detail and try to spot the sniper, but the sniper could be anywhere from 40m to 300m away, there are at least 50 windows, people running around at ground level, and vehicles going around. Target Number: 18 (yes, I pulled that number out of my ass, but that's what GM's do. ).

I wouldn't allow the use of the vision mag until he spots a likely source since it would take ages to scan the entire street looking through the magnification.

Posted by: TinkerGnome Oct 30 2003, 08:15 PM

SR Thermo doesn't work on infrared? Umm...

Posted by: Shadow Oct 30 2003, 08:30 PM

Well theres the problem, heat and IR are not always the same thing. In the service I wore low-light goggles called NODS. They were lowlight goggles (they amplified starlight). However, they had a IR attachment that if you turned on acted as a flashlight. So that's real life, not SR.

In SR I have seperated the two, but I must have missed the ref to IR.

I guess it is I who has confused SR and Realife

Posted by: Ed_209a Oct 30 2003, 08:32 PM

IRL, all low-light optics are also sensitive to part of the IR spectrum. It is standard practice for soldiers to use tiny IR lights to operate in darkness. Most night vision goggles even have a little IR light built in.

[edit]
Synchronicity, eh, Shadow?
[/edit]

Posted by: Ed_209a Oct 30 2003, 08:35 PM

In my last SR session, I made one of the characters navigate a sewer through the thermo scope of his sniper rifle because he only had Low light eyes, and didn't bring a light.

Posted by: Game2BHappy Oct 30 2003, 08:40 PM

Here is a decent article on http://www.infraredthermography.com/irvsvis.htm

It discusses the differences between "infrared night vision" and "infrared thermography". The quick breakdown is reflected vs. emitted infrared light.

Here are a couple sites with interesting infrared and thermogram images:

http://www.htiweb.com/Laser_N_Optics/IR_image1.gif

http://www.midwestinfrared.com/gallery.htm

IMO, I use thermo as a thermogram which allows the character to see somewhat in complete darkness (which is why thermographic gets only a +4/+2 in complete darkness), unlike normal "infrared night vision" which is really low-light vision.

Posted by: Cray74 Oct 30 2003, 08:45 PM