Night Vision Goggles usage
 

This is about NVGs (Night Vision Goggles)

I wanted to request for opinions for further clarity on the issue on electrical power utilisation by the NVGs (Please read- battery power) working on the principle of image intensification.

"Would that be true to say that during 'Better' lit up conditions by night, since the illumination enhancement required would be lesser as compared to a dark phase night (lets say) the consumption of battery power would be lesser."

Alternatively, possible hours of usage for a pair of batteries used only during the full moon days would be more than if they are used only during the'new moon' days- rest all conditions being identical.

My understanding of the topic indicates that this won't happen- the NVGs don't have a feedback system to 'maintain' a constant level of illumination through the phosphorus screen.

Well that's so far I can see.

Would appreciate comments

Thanks for the read anyway...

My understanding of it (and anyone who knows better feel free to correct/ ridicule me) is that a constant load is put on the power source to power the displays and processors and the amount of ambient light has little to nothing to do with the amount of power consumed.

NVGs don't make light, they simply amplify already existing light and the "brightness" of the image seen by the human remains the same. The NVGs simply adjust the electronic aperture to allow an appropriate amount of light into the gogs much like a human pupil.

Hope that helps! :8

Yep - they are pure 'illumination intensifiers' - and hence the power requirement is pretty much constant and not dependant on the ambient light conditions.

When in well lit - or brighter - environments they tend to brighten the picture up to a maximum setting - and everything just appears very bright - this can mean that some items are lost in the 'glare' - they are often said to 'back down' ie not show everything, however this is an illusion and they have just reached their maximum threshold.

When in very dark conditions they generally work well down to about 1 millilux - below that - while still capable of intensification, they tend to add their own lights - and you have a 'snowflakes' effect where random points of light 'flicker' around - not generally distracting but a good indicator that your are in poor light levels.

Cheers
LC

very informative. thanks

As kharmael says
 

NVGs amplify what they see - generally speaking the 'light' they amplify is within the ' Near Infra Red' spectrum- above 600nm - therefore just outwith the visible spectrum (dependant upon the NVG and the 'minus blue' filter attached to the NVG- if the operator is new to this technology don't assume that the NVGs have a minus blue filter fitted as standard- I have been caught out by this in Poland!)