Originally Posted By: SkyPupHere is a graph of the relative spectral sensitivities of the human eye vs. the relative spectral sensitivity of a GEN III night vision optic.
As you can see, the peak of sensitivity for human beings is in the green (550nm) wavelengths with the least ability to detect either purple (400nm) or dark red (720nm) wavelengths at either end of the visual spectrum.
The reason being is that the three retinal cone opsin proteins that are excited by these wavelengths to detect visible light in mammals (warm blooded animals including but not limited to humans, coyotes, rats, etc,) are only excited specifically by these "visible" light waves, the entire rest of the electromagnetic spectrum is 100% totally invisible because all those other wavelengths do not interact with any of the three highly evolutionary conserved opsin proteins in warm blooded animals.
In particular, the red light wavelengths have the weakest amount of electromagnetic energy of ALL the visible light wavelengths and are the most difficult to detect and see and differentiate.
Everything over 720nm is invisible to humans and coyotes and must be detected with a NVO, since it is invisible without a NVO.
If you or a coyote see a red light at night, you are NOT seeing IR, you are seeing visible light because visible light is not invisible, however IR light has been invisible light for millions of years and will continue to be invisible to the naked eye with the use of NVOs for the foreseeable future....
P.S. - it is also quite valuable information to note that NVO GEN III optics are MOST SENSITIVE in the 750nm to 850nm range!
Good post as always.
P.S. I underlined another statement you made for those white phosphor NVD's with clever marketing that somehow white is better to see that green phosphor.
Vic