Thermal image scope...what do I need to know about them?

[MAJK]

Thermal image scope...what do I need to know about them?

I'm picking up a scope next weekend but dont know much about them. Do they wear out? is it like NV where the tube burns out over time? How can I tell if its a good scope? Its a Magnavox HHTI AN/PAS-19 scope if that matters.

[J_Dub_503]

I would suggest contacting TNVC or look for clasky here on the forum.

[MAJK]

I would suggest contacting TNVC or look for clasky here on the forum.

sent him a IM

[JSantoro]

No, the processor that provides thermal observation capability is not the same as a GenII/GenIII intensifier tube that provides light-based image-intensification capability. You're using completely different, though related, wavelengths of energy on the electromagnetic scale.

A thermal device detects differences in the amount of heat being emmitted by different objects, as compared to a background temperature. The processor provides a visual intepretation of that info to a screen. They're not particularly vulnerable to exposure to sunlight, though it's a good practice to turn off the device and put the lens cover on when not in use.

Image intensifiers take light photons, change them into electrons, multiply them by a factor of 10,000X or so, then turn them back into photons to be used to create an image. These ARE sensitive to light, and must be turned off and the lens covers applied to prevent tube burnout, ghost image imprint, or other types of damage.

Thermal works in all lighting conditions, though works better at night when the land is "cold" and all the stuff moving around shows "hot." It's all about the comparative temps within the device's view. If everything within its view is the same or close to the same temp, you won't see much detail. So, noon/early afternoon in the desert will require lots of gain/level/contrast/etc adjustments to see a reasonably clear image, but the same environment an hour prior to dawn will make mammals stand out like a turd in a punch-bowl.

Wet particulates will severely interfere with capability, so fog and oily smoke almost completely obscure a scene. Same with heavy enough snow or rain, though to a lesser degree.

Given the type, it's gonna be somewhere on the same basic capability level of the first-flight PAS-13s; this is late 90s thermal technology, when the best possible imagery in that medium was only possible if one had a cooling unit that needed to be housed on an airframe or in a turret. This will similarly be a "cooled" thermal, though smaller in scale. When turned on, it'll make a whirring sound; normal, means the the mechanism that takes it to and keeps it at its operating temp is working.

Cooled thermal = battery hog, worse in hot climates, and may use power source that's not readily available....I simply can't tell from the images I'm seeing if it uses the same rectangular comms-type batteries as a PAS-13 or PAS-21.

Yes, like anything, it can and will wear out, and need periodical calibrations. Are such services, and spares, available? No way to know except contacting the manufacturer.

Oh, and don't clean the lens by licking it. Glass absorbs thermal energy too well to use it to make lenses, so thermal device lenses are made of germanium, which is toxic. Not "kill you" toxic, but "extraordinarily unhappy for a few hours" toxic.

Honestly, in the face of what's currently available, I'd only call this type "good" in comparison to a total lack of thermal capability. That said, knowing that current devices start around $10k, I understand why something like this -19 might be appealing. I'd be leery about spending even a comparatively small amount on a thermal version of a Bic lighter; the question to ask if whether or not you're really saving any dough on something that one might not be able to get serviced....?

Other side of that coin is, if it's not being heavily used or batted about as it would when mounted to a crew-served weapon, it could last an incredibly long time if it's in decent shape to begin with.

[MAJK]

thanks for the reply but I'm still not sure if its worth buying. The price is less than 3rd gen NV and its an actual scope. However, I dont know if its wornout or still good. So, how can I tell if it still has life left in it? If the image is clear? Its an Airforce trade in if that matters. Cant imagine that the AF does much with any of its weapon mounted sights...and most likely isnt used much.

[JSantoro]

Unless you have the ability to finger-bang it for yourself prior to the sale and delivery, you have no way of knowing it's condition until it's in your hands. That's regardless of whom it's original owner happened to be.

Yeah, the PRICE may be less (I'm seeing a 2.5x magnification, GenIII, dot-reticle device from a known-good manufacturer for $1800...)

...but would it be of better VALUE to you than a GENIII clip-on or dedicated scope....current technology, readily-available power sources (i.e., common batteries), a vendor/manufacturer that can fix it if it goes tits-up....etc.?

Most folks that inquire into thermals for reasons other than duty-type use are doing so for either the exotic factor (which is fine, that's not a dig...), or are looking for a truly passive target observation/reduction capability(as opposed to an I-square device used in conjunction with an active IR illuminator and /or aimer) in a limited-vis environment.

Anyhow, the cnetral question is always: What is your intended usage? I.e.....
-to what range are you hoping to detect
-to recognize
-to identify
...a target?

-what kind of target(s)?
-under what limited-vis conditions?
-is active, IR light a no-go?
-if YES, why?
-is weapon-mounted a "must-have" capability?

This is not to talk you out of the purchase....to this day, thermal is still cool as hell, man...but to take a realistic look at it. You already touched on the "not sure" aspect, so let's categorize what's behind what might make it worth the risk....or not.

[MAJK]

the question isnt if I need it or not. The question is how can I tell if its a good unit when I meet FTF and look at/through it. Thats the question.

What I will be using it for still isn't the question either. Nevertheless, I will be using it for shooting at night on a ranch with a suppressed M4 or FAL. Range will be 25 to 200 yards. Targets will be ratcoons, cyote, hogs or whatever else tries to kill the chickens.

I already have 3rd gen NV and 5 IR Lasers.

[a0cake]

You asked a pretty general question and I think JSantoro gave you a thoughtful response. Definitely some things to think about even if it's not exactly what you wanted. Although now that I see your intended use, I'd agree that a thermal sight, even an older one like this, would probably be a good solution.

Anyway, although I've used all kinds of thermal optics extensively, I can't answer your question about expected lifespan, how to tell how much legs the thing has left, etc. When they broke, they just got turned in so I've never thought about it.

But I can tell you that the older PAS-13's (never used a 19, but it seems to be even more of a clunker), DO go down with some degree of frequency. One second it works, the next it just won't fire up. There were a variety of issues with the older PAS's going down before the newer generation stuff came out around '06 and the even newer ones more recently, which are much better. The 19 is many generations old, and without knowing the history of the individual unit you're looking at, my money would be on it going down sooner than later, based on what I've seen out of the 13's of a similar era.

I honestly don't know what kind of support / repair channels there are for civilian owners. If there are none, I'd hate to see you end up with a $2,000 paper weight.

Unless you're super rich (which it seems you may be from your extensive NV equipment and IR lasers), and can afford a newer version 13C LWTS or even better the CNVD-T (which may be upwards of 20K...honestly don't know...but that thing is amazing), I would stay away from Thermals unless there's an effective support network in place and you can deal with the mediocre performance of the old units.

[JSantoro]

Nuts, my bad....

You won't see an image on the screen immediately on a cooled thermal. If this one is similar to the PAS-13B in that regard, it should take about 2min, more or less, for it to reach operating temp and form an image. It should be making a whirring or buzzing noise, which may or may not get quieter as it hits operating temp, though it shouldn't be particularly loud. Normal.

If it's loud....like, audible from 20' away, that's not good.

Usual warning, make sure the lens cover is off before proclaiming that it's not working. Happens all the time....

The image is going to be more pixellated than your I-square equipment, so be prepared for that. Normal. The resolution won't be great, but you should be able to recognize, say, a human form for what it is at 100m, in the daytime. Without knowing the specific capabilities of the system, I can't define that particularly well like I could with something like the aforementioned PAS-13B.

Make sure that any control features that exist function as they should. Most common are polarity, gain, and brightness.

-Polarity is your white-hot/black-hot control. The first shows hotter temps as brighter colors, colder as darker, and vice-versa.

-Gain is essentially your contrast control. This makes the processor show more or less detail in how it displays differences in temperature. If you fiddle with that, and you lose detail to a given image to the cold side on one end, hot side on the other, and have a reasonable level of detail in the middle, it's doing what it's supposed to.

-Brightness is purely a screen/image control, and is exactly what it's called. Makes the whole image brighter or darker.

Look for missing "channels," which may manifest in the form of horizontal bars across the FOV. I've seen as many as 6-10 at once, all right next to each other, that took up 25% of the screen, and the only thing that kept that from rendering it useless is that it was at the very top. Bad channels are....well, BAD.

If there's a zoom feature, work that to make sure it works. Could be electronic or mechanical, or both may be present.

If it has a focus (not all of these things do, it might be focused from about 15m to infinity), make sure the focus functions. A device this old will most likely have a manual focus ring, instead of electronic near-focus/far-focus buttons found on current devices.

This thing was made for belt-feds, so it's got to have a reticle or reticles, plural. Make sure that they adjust, azimuth and elevation. Here's where having a readable user manual is a great idea, in case it has a control feature for this that does different jobs based upon HOW you manipulate it (EX: does one thing if you press/release, does another if you press and hold for 2sec)

[SMETNA]

Thoughts on a handheld optic like the FLIR PS24 or the L-3 ThermalEye X-50?

Worth the $2,000 - $3,000? (vs. Gen 3 Night Vision for the same kind of money, i.e. AN/PVS 14)