Need your help on: Night Vision Devices

[B.T.]

There is a great chance, that during my next FtF-session there will be a bigger firefight, involving at least three different groups of enemies. This battle will take place in a ruined village. The PCs are sitting in an abondened warehouse, about three floors/storeys high, at the edge of the village. At least one of the enemy groups will be in an open environment. Right now, it is about 7 p.m., nightset will be at 10:30 p.m. This will supposingly be the time, when the fighting starts.
Chances are high, that several units involved will use night vision devices. Some questions occured, I really don't know the answers, and your help would be appreciated.

1. One of the PCs uses an AN/PEQ-2. If one of the enemy soldiers uses IR-Goggles, is it easier to fire at the PC with the LAD? If, how could that be handled? Making the roll for the enemy one difficulty level easier?
2. Several guys use IR-Goggles, or starlight scopes, one person is equipped with a x25 image intensifier. How do the different devices react to sudden bright light? (Most soldiers involved (friend and foe alike) don't have any vision device. Several people have a grenade launcher with them and will certainly fire some ILLUM grenades.) If a user of a night vision device spots an area, that is illuminated by a 40mm ILLUM grenade, will the user of IR-Goggles/starlight scope/image intensifier temporarily be blinded?
3. What about Thermal Sights on a tank? There will be no tank with Thermal Sights involved in this fight, but nonetheless: Do Thermal Sights have any benefit for their user during daylight (e.g. spotting a heat source like an enmy tank behind a thin brick wall)? Reason for this question: I have read about several incidents during the Gulf War, where U.S. tankers spotted enemy tanks behind dunes. This did happen because of the Thermal Sights, right?
4. How much detail can one see, using those aforementioned vision devices? Is it possible to spot the differences in different camouflage uniforms or individual faces?

I use (slightly expanded) Ver.2.2 rules. I know, that the soldier with the AN/PEQ-2 needs IR-Goggles himself. I use the ”Tactical Visibility“ rules from the BYB, p. 223. The background light level is 2 (Very early waxing crescent, new moon was two nights ago. During the night, clouds will build up, so the starlight is somewhat muted/subdued.).

[Targan]

If you are using a thermal sight and can see an enemy tank behind a dune I think it is because you can see the heat plume rising from the tank's engine and exaust, not because the heat is penetrating the dune.

[ArmySGT.]

Originally Posted by B.T.

There is a great chance, that during my next FtF-session there will be a bigger firefight, involving at least three different groups of enemies. This battle will take place in a ruined village. The PCs are sitting in an abondened warehouse, about three floors/storeys high, at the edge of the village. At least one of the enemy groups will be in an open environment. Right now, it is about 7 p.m., nightset will be at 10:30 p.m. This will supposingly be the time, when the fighting starts.
Chances are high, that several units involved will use night vision devices. Some questions occured, I really don't know the answers, and your help would be appreciated.

Illumination as provided by the moon and stars is important, and the cloud cover. These work best and have the longest detection ranges under a full moon. Dark overcast night cut detection ranges in half.

Originally Posted by B.T.

1. One of the PCs uses an AN/PEQ-2. If one of the enemy soldiers uses IR-Goggles, is it easier to fire at the PC with the LAD? If, how could that be handled? Making the roll for the enemy one difficulty level easier?

Depends on the dust and smoke in the air. It is a laser pointer essentially. Without dust you can’t see the beam, with dust in the air, you can follow it back to the source.

Originally Posted by B.T.

2. Several guys use IR-Goggles, or starlight scopes, one person is equipped with a x25 image intensifier. How do the different devices react to sudden bright light? (Most soldiers involved (friend and foe alike) don't have any vision device. Several people have a grenade launcher with them and will certainly fire some ILLUM grenades.) If a user of a night vision device spots an area, that is illuminated by a 40mm ILLUM grenade, will the user of IR-Goggles/starlight scope/image intensifier temporarily be blinded?

x25 Image intensifier is like a night vision spotting scope for Artillery Observers. Not so useful in a firefight. This beast is heavy and bulky. NV gear resets it bright light to protect the electronics. Current generation stuff, auto dims, it automatically scales down the light gathering to protect the electronics. Old 70s models would shut off and could take a minute to come back on.
I think doctrine is the same for both sides. When a flare goes off overhead every finds cover, closes their firing eye to protect night vision, and scans the terrain with their non-firing eye. This is a very good time to look around for obstacles, prepared enemy positions, get yourself oriented (North –South), look for hand signal from leaders, and top off magazines or check your buddies bleeding. So actually when are flare lights up there is a lull in the shooting.

Originally Posted by B.T.

3. What about Thermal Sights on a tank? There will be no tank with Thermal Sights involved in this fight, but nonetheless: Do Thermal Sights have any benefit for their user during daylight (e.g. spotting a heat source like an enmy tank behind a thin brick wall)? Reason for this question: I have read about several incidents during the Gulf War, where U.S. tankers spotted enemy tanks behind dunes. This did happen because of the Thermal Sights, right?

Tankers in the Gulf could see the heat plumes of tanks hidden behind dunes, walls, and in Wadis. The could tell live from dead tanks. The advantage the thermals will provide is they see through smoke. Smoke grenades will not be concealment. You will spot guys behind curtains, and peeking through holes in damaged buildings. Bad guys can’t hide in the back of the room in the shadows and observe outside.

Originally Posted by B.T.

4. How much detail can one see, using those aforementioned vision devices? Is it possible to spot the differences in different camouflage uniforms or individual faces?

At 100 meters with a set of AN/PVS-7Bs you can tell one person from another. When they get close enough you can read their name of their uniform. You can read a newspaper in your hands.

Originally Posted by B.T.

I use (slightly expanded) Ver.2.2 rules. I know, that the soldier with the AN/PEQ-2 needs IR-Goggles himself. I use the ”Tactical Visibility“ rules from the BYB, p. 223. The background light level is 2 (Very early waxing crescent, new moon was two nights ago. During the night, clouds will build up, so the starlight is somewhat muted/subdued.).

I don’t know this rule set.

[Legbreaker]

Originally Posted by ArmySGT.

I don’t know this rule set.

The following is from 2.0

TACTICAL VISIBILITY
Normal daylight visibility is effectively unlimited, restricted only by intervening terrain and the curvature of the earth. (For a person of normal height standing on a flat plain, the horizon is about five kilometres distant.)
Smoke, adverse weather, and night reduce visibility severely. Dense smoke blocks visibility completely. Light smoke obscures characters and vehicles in and beyond it. In poor weather (light fog, drizzle, and light snowfall), maximum visibility distance is 2000 metres for moving vehicles, and very large objects and structures (such as villages, woods, etc.). For stationary vehicles, small structures (such as bunkers), and moving people, the maximum spotting distance is 1000 meters. For stationary people, it is 500 meters. In bad weather (dense fog, rain, and heavy snowfall), these distances are quartered.
Visibility at night varies considerably, depending on the amount of background light. The referee should assign a background light level of from one to five, with one representing a cloud covered, moonless night (in other words, pitch black) and five a clear night with a full moon high in the sky. Visibility for large structures and moving vehicles is 400 meters times the background light level. Visibility for small structures, stationary vehicles, and moving people is 200 meters times the background light level. Visibility for stationary people is 100 meters times the background light level. Halve the distance for poor weather at night; quarter the distance for bad weather at night.
Encounter Ranges: In poor weather halve all encounter ranges (except in woods). In bad weather, quarter all encounter ranges (except in woods). At night, multiply all encounter ranges (except in woods) by background light level and divide by 10, then modify for poor or bad weather. (Woods are unaffected by reduced visibility, as visibility is already so limited that encounter range depends as much on hearing the encounter seeing it anyway.)
Vision Enhancement Devices: A number of vision enhancement devices are available. They have the following effects.
Binoculars: Binoculars are useful only during periods of good visibility (daylight and good weather). A character who is equipped with binoculars and is in a good observation position (building roof, treetop, hill) has his Observation skill increased by one. If he spots a group before they spot him or the rest of his party, double the range of the encounter.
Starlight Scope: A player using a starlight scope can see twice as far at night as he could without the scope. In an encounter situation, this would allow characters with starlight scopes to begin rolling for spotting before hostile groups would be able to attempt to spot them. Starlight scopes have no effect in woods, smoke, or poor or bad weather.
Image Intensifier: An image intensifier has same effect as binoculars, except that the character adds two to his Observation skill. The device incorporates both telescopic and low-light intensification, and has a maximum range of 900 meters. Image intensifiers have no effect in woods, smoke, or poor or bad weather.
IR Goggles: Infrared goggles allow a character to see moving or stationary personnel or other heat sources at a distance of 300 meters at night. In addition, a character wearing infrared goggles can see the beam of an IR spotlight. IR goggles have no effect in woods, smoke or poor or bad weather.
IR Spotlight: An infrared spotlight can illuminate an area 20 meters across at a range of up to 1000 meters. Only characters wearing IR goggles can see the light.
However, any character wearing IR goggles will see the searchlight if he is within 3000 meters of it. IR spotlights have no effect in woods, smoke, or poor or bad weather.
White Light Spotlight: A white light spotlight will illuminate an area 20 meters across at ranges up to 2000 meters. The light itself can be seen by any character at any distance who has a clear line of sight to it. White light spotlights have no effect in woods, smoke, or poor or bad weather.
Thermal Sight: A thermal sight is a very advanced form of infrared imaging. It allows characters to see vehicles out to 3000 meters and people out to 2000 meters through darkness, smoke, and fog. This range is halved in drizzle and rain, and the device has no effect in snowfall and woods.
Illumination Rounds: An ILLUM round will illuminate the area within its burst radius as if it were full daylight. ILLUM rounds have no effect in woods, smoke, or poor or bad weather.

2.2 is almost identical.

[B.T.]

Originally Posted by ArmySGT.

Snip ...
Depends on the dust and smoke in the air. It is a laser pointer essentially. Without dust you can’t see the beam, with dust in the air, you can follow it back to the source.

Snip ...

Tankers in the Gulf could see the heat plumes of tanks hidden behind dunes, walls, and in Wadis. The could tell live from dead tanks. The advantage the thermals will provide is they see through smoke. Smoke grenades will not be concealment. You will spot guys behind curtains, and peeking through holes in damaged buildings. Bad guys can’t hide in the back of the room in the shadows and observe outside.

Thank you, ArmySGT,
I've asked for the AN/PEQ-2 in particular, because the beam is invisible, if the user does not have a device for seeing in the IR spectre. If I understand that right, the dust in the environment should not be that important, because the beam would still be unrecognizable for persons without IR-Goggles?

Leg quoted the rule. Ver 2.2 is (more or less) the same.

As Targ and ArmySGT pointed out, the tankers with Thermal Sights can spot the plumes. Does this even apply in daylight?

Thanks so far, as usual very good info!

[ArmySGT.]

Originally Posted by B.T.

Thank you, ArmySGT,
I've asked for the AN/PEQ-2 in particular, because the beam is invisible, if the user does not have a device for seeing in the IR spectre. If I understand that right, the dust in the environment should not be that important, because the beam would still be unrecognizable for persons without IR-Goggles?

Yes, persons without IR goggles can't see the PEQ-2 in IR mode. I don't recall if it has the visible red laser mode too.

Originally Posted by B.T.

Leg quoted the rule. Ver 2.2 is (more or less) the same.

As Targ and ArmySGT pointed out, the tankers with Thermal Sights can spot the plumes. Does this even apply in daylight?

Thanks so far, as usual very good info!

Yes, it is the heat mirage. Like the distortion you see as heat comes off hot asphalt. Kinda like smoke.

[bobcat]

the AN/PEQ2 does not have any visible mode. you can spot the laser emitter but as it does have a shroud around it you'd have to be directly in front of the laser which is generally a bad place to be and you'd have a better chance spotting the muzzle flashes or following the IR flashlight that is built into the sight. hovever you can follow the beam back in a dusty or smokey environment(ie any combat/training environment i've ever seen)

[James Langham]

As an aside, British doctrine when caught in a flare depends on your location:

* in the open - drop prone immediately

* in cover - freeze in place as the movement is the most likely way to be seen.

In both cases close the shooting eye.

[TicToc]

Originally Posted by B.T.

1. One of the PCs uses an AN/PEQ-2. If one of the enemy soldiers uses IR-Goggles, is it easier to fire at the PC with the LAD? If, how could that be handled? Making the roll for the enemy one difficulty level easier?

Anyone with a NVD will be able to see any kind of emitted IR energy. Depending on atmospheric factors (dust, fog, ect ect) it will either look like a full beam leading back to the source (in this case the PC) or it will appear as a bright dot of light at the source and point of termination.

Originally Posted by B.T.

2. Several guys use IR-Goggles, or starlight scopes, one person is equipped with a x25 image intensifier. How do the different devices react to sudden bright light? (Most soldiers involved (friend and foe alike) don't have any vision device. Several people have a grenade launcher with them and will certainly fire some ILLUM grenades.) If a user of a night vision device spots an area, that is illuminated by a 40mm ILLUM grenade, will the user of IR-Goggles/starlight scope/image intensifier temporarily be blinded?

I'm not experienced with older NVDs but my understanding is that they would washout in a very bright way not only destroying the night vision of any PC for a significant period of time but the device would shutdown due to damage.

Originally Posted by B.T.

3. What about Thermal Sights on a tank? There will be no tank with Thermal Sights involved in this fight, but nonetheless: Do Thermal Sights have any benefit for their user during daylight (e.g. spotting a heat source like an enmy tank behind a thin brick wall)? Reason for this question: I have read about several incidents during the Gulf War, where U.S. tankers spotted enemy tanks behind dunes. This did happen because of the Thermal Sights, right?

Thermal imagers don't see through anything. In fact thermal imagers cant see through glass or even a bed sheet (unless the heat producing source is hot enough to warm the barrier. Termal imagers work as well in the day as they do in the night. They do however not work very well during thermal crossover (essentially the 30-60 minutes after down and after sunset.) The reason for this being the rate at which the atmosphere and objects cool creates a situation where objects blend in and due to like temperatures and detail is greatly lost.