# Night Vision Goggles in Absolute Darkness **URL:** \ **Category:** Factual Questions\ **Created:** [January 1, 2010, 4:52pm UTC](https://boards.straightdope.com/t/night-vision-goggles-in-absolute-darkness/523302 "2010-01-01T16:52:54Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![HeyHomie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/heyhomie/32/207_2.png) [@HeyHomie](https://boards.straightdope.com/u/HeyHomie)\ **Post date:** [January 1, 2010, 4:52pm UTC](https://boards.straightdope.com/t/night-vision-goggles-in-absolute-darkness/523302/1 "2010-01-01T16:52:54Z")
My understanding of night vision goggles is that they amplify existing light; so ferinstance, a soldier patrolling the desert at night can get by with the light cast by the stars & moon thanks to his goggles. Would these work in absolute darkness, like in a photographer’s darkroom or something? ---
**Author:** ![Chief\_Pedant](https://avatars.discourse-cdn.com/v4/letter/c/a6a055/32.png) [@Chief\_Pedant](https://boards.straightdope.com/u/Chief_Pedant)\ **Post date:** [January 1, 2010, 4:57pm UTC](https://boards.straightdope.com/t/night-vision-goggles-in-absolute-darkness/523302/2 "2010-01-01T16:57:40Z")
My video camera paints the surroundings with infrared in absolute darkness if there is no ambient light at all; it occurs to me the same technology could be (and probably is) applied to night vision devices when there is no light to amplify. See here, for instance: " **Active infrared** \*Imaging results with and without active-infrared.Active infrared night vision combines infrared illumination of spectral range 700nm–1000nm – just below the visible spectrum of the human eye – with CCD cameras sensitive to this light. The resulting scene, which is apparently dark to a human observer, appears as a monochrome image on a normal display device.[4] Because active infrared night vision systems can incorporate illuminators that produce high levels of infrared light, the resulting images are typically higher resolution than other night vision technologies.[5][6] Active infrared night vision is now commonly found in commercial, residential and government security applications, where it enables effective night time imaging under low light conditions. However, since active infrared light can be detected by night vision goggles, it is generally not used in tactical military operations.\*" > **[Night vision](https://en.wikipedia.org/wiki/Night_vision#Active_infrared)** > > Night vision is the ability to see in low-light conditions, either naturally with scotopic vision or through a night-vision device. Night vision requires both sufficient spectral range and sufficient intensity range. Humans have poor night vision compared to many animals such as cats, foxes and rabbits, in part because the human eye lacks a tapetum lucidum, tissue behind the retina that reflects light back through the retina thus increasing the light available to the photoreceptors. > Night-useful... ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [January 1, 2010, 4:58pm UTC](https://boards.straightdope.com/t/night-vision-goggles-in-absolute-darkness/523302/3 "2010-01-01T16:58:04Z")
> [@HeyHomie](#): > > My understanding of night vision goggles is that they amplify existing light; so ferinstance, a soldier patrolling the desert at night can get by with the light cast by the stars & moon thanks to his goggles. > > Would these work in absolute darkness, like in a photographer’s darkroom or something? No, they won’t work in complete darkness, but you can use an Infrared light source to provide supplemental lighting. ---
**Author:** ![Xgemina](https://avatars.discourse-cdn.com/v4/letter/x/b5e925/32.png) [@Xgemina](https://boards.straightdope.com/u/Xgemina)\ **Post date:** [January 1, 2010, 5:14pm UTC](https://boards.straightdope.com/t/night-vision-goggles-in-absolute-darkness/523302/4 "2010-01-01T17:14:45Z")
I can tell you that the NVG-7Bs that I used in the Army did not work in really dark nights (starless/cloudy/no moon) out in the woods/desert. As **beowulff** said, however, they did have a setting for infrared and with the use an infrared light they would work for a very short distance. ---
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [January 1, 2010, 6:59pm UTC](https://boards.straightdope.com/t/night-vision-goggles-in-absolute-darkness/523302/5 "2010-01-01T18:59:05Z")
> [@Xgemina](#): > > I can tell you that the NVG-7Bs that I used in the Army did not work in really dark nights (starless/cloudy/no moon) out in the woods/desert. As **beowulff** said, however, they did have a setting for infrared and with the use an infrared light they would work for a very short distance. An issue with active infrared illumination is that to an opponent with passive viewing devices it’s as though you were using a regular flashlight. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [January 1, 2010, 11:12pm UTC](https://boards.straightdope.com/t/night-vision-goggles-in-absolute-darkness/523302/6 "2010-01-01T23:12:27Z")
> [@beowulff](#): > > No, they won’t work in complete darkness, but you can use an Infrared light source to provide supplemental lighting. > [@Xgemina](#): > > I can tell you that the NVG-7Bs that I used in the Army did not work in really dark nights (starless/cloudy/no moon) out in the woods/desert. Doesn’t virtually everything radiate some IR even if it’s not illuminated? Especially things like enemy combatants who generate their own heat? ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [January 2, 2010, 6:01am UTC](https://boards.straightdope.com/t/night-vision-goggles-in-absolute-darkness/523302/7 "2010-01-02T06:01:45Z")
> [@CookingWithGas](#): > > Doesn’t virtually everything radiate some IR even if it’s not illuminated? Especially things like enemy combatants who generate their own heat? The NVGs I’ve used have only been able to use the near IR and the natural IR given off by objects wasn’t enough, you needed the IR torch or some ambient light. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [January 2, 2010, 6:06am UTC](https://boards.straightdope.com/t/night-vision-goggles-in-absolute-darkness/523302/8 "2010-01-02T06:06:56Z")
> [@CookingWithGas](#): > > Doesn’t virtually everything radiate some IR even if it’s not illuminated? Especially things like enemy combatants who generate their own heat? This is called [FLIR](http://en.wikipedia.org/wiki/Forward_looking_infrared) and is a much more complicated and expensive device. In order to “see” the long-wave IR emitted by people, the sensors usually need to be cooled well below room temperature (often to cryogenic temperatures), which make these systems impractical to mount on goggles (with current technology). ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [January 2, 2010, 6:27am UTC](https://boards.straightdope.com/t/night-vision-goggles-in-absolute-darkness/523302/9 "2010-01-02T06:27:24Z")
> [@beowulff](#): > > This is called [FLIR](http://en.wikipedia.org/wiki/Forward_looking_infrared) and is a much more complicated and expensive device. In order to “see” the long-wave IR emitted by people, the sensors usually need to be cooled well below room temperature (often to cryogenic temperatures), which make these systems impractical to mount on goggles (with current technology). Indeed. The FLIR that we use for work is cooled to about 75 Kelvin I think. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [January 2, 2010, 3:56pm UTC](https://boards.straightdope.com/t/night-vision-goggles-in-absolute-darkness/523302/10 "2010-01-02T15:56:58Z")
[quote=“1920s Style “Death Ray”, post:9, topic:523302”] Indeed. The FLIR that we use for work is cooled to about 75 Kelvin I think. [/QUOTE] You have FLIR on the Dash? Tell us (me) more please. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [January 2, 2010, 10:02pm UTC](https://boards.straightdope.com/t/night-vision-goggles-in-absolute-darkness/523302/11 "2010-01-02T22:02:00Z")
I work for [Cobham](http://www.cobham.com.au/mission.htm) who have a contract to provide aircraft and crews for Australia’s Border Protection Command (BPC). We do maritime surveillance and the sensor suite in our Dash 8s includes a Wescam FLIR and Raytheon search Radar. You can see the FLIR on [this photo]([http://www.airliners.net/photo/Untitled-(Cobham-Special/De-Havilland-Canada/1579026/M/)](http://www.airliners.net/photo/Untitled-(Cobham-Special/De-Havilland-Canada/1579026/M/)) just behind the nose gear doors. BPC is a fairly recent renaming of what used to be Customs Coastwatch and the aircraft have retained the Customs and Coastwatch markings as well as Coastwatch radio callsigns. I should add that it (the FLIR) is used for gathering information from the boats we find rather than anything exciting like night approaches into unlit aerodromes ;).