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what I learned about thermals over the weekend

Posted By: RiverRider

what I learned about thermals over the weekend - 12/06/23 06:25 PM

I spent three nights in San Saba hunting hogs. I got three the first night but got skunked the following nights, seeing only one armadillo both nights. Sometimes that's just how it goes, but it's always amusing. I had a little additional amusement Monday night sitting in the blind.

Since it was a little chilly and I had a breeze blowing in directly in my face, I closed a few of the windows for my own comfort. Some time later I picked up my Pulsar scanner to have a look around. I normally scan all around me, even though I'm fairly sure I won't see anything looking out certain windows because you never know...and out of habit I pointed the thermal toward a window I had closed earlier. I saw odd patterns on the glass, as though frost had formed in random shapes. I saw similar patterns in the other two windows. I just thought "Hhmmm...weird," and set the device down on the shelf. After wondering about it for a few minutes, I felt the glass, and it just was not cold enough to form frost and there was no condensation . "Hhmmm," I thought to myself. The next time I scanned I decided to take another look and see if I could make anything of these patterns I was seeing. First, one smaller window...yeah, there were shapes but I couldn't make sense of any of it. I looked at a larger window studying the shapes I was seeing. All in a matter of about two seconds, I noticed a shape like a nose and a mustache, and when that realization hit me I saw features of a face, which made the hairs on my neck stand on end. When the shock of seeing the face subsided I realized that the face had something other than an eye on one side, and then I realized I was seeing a thermal reflection of myself looking back at me.

I felt pretty silly for having been startled, but I was the only one around to laugh at me so that is what I did.

Just thought I'd share that for entertainment's sake.
Posted By: Judd

Re: what I learned about thermals over the weekend - 12/06/23 07:27 PM

That's pretty funny. The technology is weird...it sees reflections in windows like it's a mirror but can't see the heat/colt through the window. Then you get night vision and it has no issues seeing through windows. Crazy.

I first noticed it on a mirror on the truck...you can see as you normally would in a mirror, wild.
Posted By: Double Naught Spy

Re: what I learned about thermals over the weekend - 12/06/23 07:48 PM

Welcome to thermal, just don't drive with it if you have a windshield, LOL.
Posted By: der Teufel

Re: what I learned about thermals over the weekend - 12/06/23 11:56 PM

Originally Posted by Judd
I first noticed it on a mirror on the truck...you can see as you normally would in a mirror, wild.

Yep, sometimes on cold nights I'll sit in my truck with the window open so I can point the thermal monocular at the outside mirror and see what's behind me.
Posted By: duffas

Re: what I learned about thermals over the weekend - 12/07/23 02:12 AM

Must have a good one, .016 degree C sensitivity. Most are >35 degree C. Not a bad D* for uncooled stuff.
Posted By: Outdoor Legacy

Re: what I learned about thermals over the weekend - 12/07/23 10:27 PM

Don't feel bad, I knew better and still...... one time late at night I walked in my back porch door while still holding a thermal monocular up to my eye. The house was dark, everyone was asleep and as I looked across the big room and into my kitchen, I happened to be looking at my chrome refrigerator door and what did I see? I man standing there looking back at me. After nearly pooping my pants I dropped I realized it was my reflection from that metal door. Whew....I nearly had to go take another shower.lol
Posted By: SapperTitan

Re: what I learned about thermals over the weekend - 12/08/23 01:55 AM

Yes you can also see animals reflections in the water like a deer standing by the edge of a tank.
Posted By: BigPig

Re: what I learned about thermals over the weekend - 12/08/23 04:54 AM

Originally Posted by Double Naught Spy
Welcome to thermal, just don't drive with it if you have a windshield, LOL.


Even if you have a windshield, you won’t see the barb wire fence, I have first hand knowledge
Posted By: duffas

Re: what I learned about thermals over the weekend - 12/08/23 03:12 PM

IR can 'see' down to 2 micron so you are 'seeing' the reflection of near visible light - not heat.
Posted By: QuitShootinYoungBucks

Re: what I learned about thermals over the weekend - 12/08/23 03:22 PM

The thread delivers! roflmao
Posted By: MWTX270

Re: what I learned about thermals over the weekend - 12/08/23 10:53 PM

Fun post. Enjoyed the read!
Posted By: Double Naught Spy

Re: what I learned about thermals over the weekend - 12/09/23 02:31 PM

Originally Posted by duffas
IR can 'see' down to 2 micron so you are 'seeing' the reflection of near visible light - not heat.


Want to give us a physics tutorial on why it isn't heat being seen reflected?
Posted By: 450bush

Re: what I learned about thermals over the weekend - 12/09/23 03:26 PM

Regular glass don’t allow the Thermal IR wavelength to go through. However it reflects it like a mirror does with the light that we can see.

This is the reason that thermal scopes uses Germanium lenses instead of normal glass lenses.

Those infrared motion detection sensors (PIR) uses the same wavelength. you can defeat them using a glass plane as a “thermal shield”!
Posted By: RiverRider

Re: what I learned about thermals over the weekend - 12/09/23 07:37 PM

Originally Posted by 450bush
Regular glass don’t allow the Thermal IR wavelength to go through. However it reflects it like a mirror does with the light that we can see.

This is the reason that thermal scopes uses Germanium lenses instead of normal glass lenses.

Those infrared motion detection sensors (PIR) uses the same wavelength. you can defeat them using a glass plane as a “thermal shield”!






I'm kinda wondering about different types of glass. When I received my first thermal maybe five or six years ago, one of the first things I did was see if I could look through a window and since it didn't appear to be practically effective I never gave it another thought.

I would imagine there are a great many varieties of glass. I would also imagine that any manufacturer of deer blind windows & glass would be interested in it IF thermally transparent glass exists and is not ridiculously expensive.


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