Infrared lights

[DB510]

There was a study in 2001 where cats and rats responded to infrared stimulus from 940 nm IR LED's

Found this interesting as the Sony "Night Shot" uses 1000 nm IR LED's.

Cats have 'eyeshine' caused by the tapetum lucidum and this eyeshine has been reported in yowie sightings. If the yowie possibly has similar night vision capabilities to cats, particularly the ability to see IR lights, could this mean that the yowie is avoiding these lights?

Has there been any instances where a yowie has seemingly avoided IR lights/cameras, either hand held or remote?

[Buck]

Hi Kwotch

There are plenty of instances of well equipped expeditions where high activity has been noted but when the tech stuff comes out, the area is avoided. Why? It's a pretty good indication of how good their night vision and their intelligence. They don't want to be seen. Even low tech stuff like placing sand traps on tracks has only resulted in the Yowie avoiding that section of track and going around it. Check out Neil Frosts accounts on you-tube.

Imagine having that vision, even before we switch on our torch, the reflector part of the torch would give your intentions away. I've helped put up a couple of game cams but even those have LED's which have some degree of reflection that comes off them let alone when they are operating at night on IR.

I work in a theatre where we are required to wear blacks so as not to be seen, even in very low light with my eyes you can see little pale faces moving about, the audience don't notice this as they are watching the show. I can only imagine how much my face stands out at night in any ambient light from the moon and the stars. I also wear glasses there's got to be some shine of those as well.

Just as we can tell if something doesn't belong or looks sus in a busy street, the Yowie will no dount be able to tell that that square shaped thing on that tree doesn't belong there. Some cameras have gone off only to reveal vague shapes in the distance beyond the effective range of the camera. I'd think that was some indication of avoidance. Better results are coming in with thermal cameras for bigfoot, it's still not the rock solid evidence that the general population would agree cements it's existence into peoples belief systems. One thing it does seem to indicate is the distance they keep from us, I guess it's a bit like that great scene in Silence of the Lambs where Jodie Foster is in pitch darkness and has no idea how close she is to the person she's looking for.

I can't remember who it is that said " You don't find yowies, they find you."

But I think that's an accurate summation of the situation.

Cheers Buck

[andrew]

There was a study in 2001 where cats and rats responded to infrared stimulus from 940 nm IR LED's

Found this interesting as the Sony "Night Shot" uses 1000 nm IR LED's.

Cats have 'eyeshine' caused by the tapetum lucidum and this eyeshine has been reported in yowie sightings. If the yowie possibly has similar night vision capabilities to cats, particularly the ability to see IR lights, could this mean that the yowie is avoiding these lights?

Has there been any instances where a yowie has seemingly avoided IR lights/cameras, either hand held or remote?

High power IR LED light sources suffer from a problem that many may be unaware of. They have a very large bandwidth, in some case as high as 45nm. That means they are emitting over a band from below 900 to nearly 985nm. The lower end may well be "visible". I recently looked into a 2W 940nm system which was in fact rated as "visible". The lower power 940nm version were rated "invisible". This is related to the emited wavelength band. Most IR camera light sources, especially the high power ones and those with older technology, have the same problem and also usually operate in the 870nm or lower wavelengths. The other problem is that if "invisible" IR light sources get hot, then they will emit in the visible IR as well just because they are "hot".

From much anecdotal evidence, I think you can be fairly confident that Yowies can see the low IR wavelengths. This is a big technical problem for high power LED IR light sources. The only solution is to use narrow bandwith sources, longer wavelengths such as 1000nm, or lasers and the latter are expensive and also pose a considerable safety risk to the operators and the animal target. Lasers beams can be diffused to reduce the danger but there is still a risk from direct face on exposure to the light.

The 1000nm Sony's system is very interesting but I would be looking closely at the response curve of the sensor first and whether they have removed the internal IR filter or made it moveable.

Andrew

[DB510]

Excellent info guys, thanks very much.

It's an interesting problem.

[DB510]

Wow, just read a huge thread on this problem, sorry, should have read that first.