Can i use a laser designator as a laser sight if it is attached to my weapon ?
( providing of course that i can see in infra red.)

Interesting question. The Extended Laser Sight weighs .25kg, costs 1500 , and gives a targeting bonus out to 150m(day)/500m(night).

The Laser Designator weighs twice as much, costs twice as much, has double the concealability penalty, and is effective as a target designator out to 10 times that range (5000m).

As a GM I think I'd house rule that a weapon-mounted Laser Designator could be used to give a targeting bonus (-1) to the shooter out to two to four times the normal range for an Extended Laser Sight. The laser light of course goes farther than that, but I'd house rule that the benefit to the shooter is not sufficient to gain the targeting bonus.

As this isn't a sourcebook question, I'm moving this topic to the wider Shadowrun forum.

the beam of a designator is usual IR, as i recall, making it invisible to the naked eye. the whole point of the designator is to mark the target without revealing your own location--drawing a glowing red line back to where you're hiding is grounds for a Darwin Award. in SR, as there are so many beings whose visual range extends into the IR, i'd say that most designators are probably in the low, low IR, below that range and into the range of radios and such.

or have someone modify the designator to have a frequency modulator built into it. you could have one toggle be the low frequency beam for laser designator purposes and the other toggle be in the visible range for laser sight purposes. i doubt it'd actually be that hard to modify

er, correction, radio isn't infrared. it's a set of colors as far below 'red' as UV is above it.

On the topic of multi-frequency designators: I doubt it. AFAIK you'd need a whole different laser tube to alter the frequency of the light, meaning you'd effectibely have something like a laser sight duct-taped to a laser designator.

Anyway: The book states that a laser designator is visible with thermographic vision; thus I'd allow someone with thermographic vision to use it as a sight, and someone with thermographic vision to spot the red dot on the target and think 'Hmm...'.

I always thought that the laser sight was just to put a straight line between you and a target, whereas the designator was to light something up electronically for another device (read: smart munitions) to be able to locate.

it is. the way it lights the target up is via a laser beam, which reflects off of the target as a specific frequency of light. the guided munition sees this light and homes in on it.

using IR-visible lasers for target designators in SR is absolutely suicidal. all it takes is one troll to look up and say "huh, an IR beam. wonder where it goes?" and your concealment is blown. any of my characters using a designator will have it specially modified to shoot a radio-frequency laser.

I thought laser sights were just a very tight-beam light, and that designators actually emitted a different sort of beam. If the laser in both is essentially the same, though, I'd guess that it would just be a simple selection between the two.

indeed. it happens, however, that my 'modification' is available as base equipment--the microwave and radio designators are exactly what i'm talking about.

holy hopped-up jesus, the radar version costs 48 grand. and it's got a 6-mile range. i... jeezus pleezus. you know why people play d20? because all of the rules in d20 are bang-your-face-on-a-brick unbelievable, not just some of them. consistency, see, that's d20's strong point.

MFB, a laser on any frequency will not draw a "glowing line" back to you unless the laser is hitting something that defracts the light. That's what makes it a laser; the light particles are all going in the same direction.

I think it would be possible to build an IR laser/laser sight as long as you found a laser tube which generated both IR and visible spectrum light. I'm sure you could optionally block one or another, perhaps using ingenious prisms or something. You would technically be shining both frequencies at the same time whenever you turn it on, but only letting one leave your designator. I don't know enough about chemistry to say if this is technically possible, and it's a real possibility that your visible spectrum color won't be red, but I think it would work.

Just to insert a bit of real-life science in here:

Firstly nezumi is perfectly correct, even a visible light laser will not draw a glowing red beam back to the user unless it is fairly foggy or dusty, in which case scatter will produce the typical visible beam. Even if the beam is in infrared, given how many people in the Shadowrun universe have thermographic vision it'll make a visible beam to about 60% of the population under such conditions as well.

Secondly, it is highly possible to make a laser that can fire in different colors. These are known as liquid dye lasers and can be "tuned" to fire in various colors. I don't quite know how that works but they do exist. There's an extremely odd one in Russia which fires not a beam, but rather a circular halo in all directions. Alas, I am not certain any liquid dye laser can fire both infrared and visible light, the only ones I have actually seen merely fired different colors of visible light.

what i hate is, is when you know a fact, but you somehow forget that fact, and then post the opposite of that fact on an online forum, and people call you on it. i hate that.