Thermal Clip-On

  • My experience with night vision equipment is relatively limited. I have run BNVS in a helmet rig with weapon-mounted IR laser/illuminator setups in the past, and that was alright, but did not offer the precision I was looking for. Certainly was great for walking around, and were I in a run & gun type scenario at night, I think I would really like that setup. Though when it comes to vermin control, I definitely wanted something a bit more precise.

    I'd love to hear what someone has to say regarding clip-on thermal sights. I played with a few at SHOT show last year, and the Eotech LWTS was the most impressive unit I handled at that time, but I didn't get hands on all of them. I really like the idea of having a dual-role thermal that can work in front of a day optic as a clip-on, but can also be mounted as a stand-alone thermal sight with it's own reticle.

    Some requirements I'd be looking for would be:

    1. Maintains zero.
    2. When using as clip on, doesn't shift day scope zero, or is at least easy to zero and is repeatable.
    3. Doesn't need frequent calibration when in use.
    4. At least 6-8hrs of continuous battery life.
    5. Works as clip-on or stand alone sight.

  • @orkan

    The BAE UTC-x comes closet to meeting your requirements of the ones I've used. Well it meets two of the five. I guess the others also meet 2 of the 5 but a different two.

    UTC-x on 6.5G(18)

    UTC-x on .300WM(24)

    UTC-x on the left, SNIPE on the right


    So the UTC-x meets the first two requirements.

    In my experience ALL thermals require frequent calibration, though the frequency depends on the thermal conditions, so the BAE, being a thermal, also requires frequent calibrations. How frequent? I'd say, ideally 5 times in the first 5 minutes, after that about 1 per every 5-15 minutes. It is best to NUC when you can, so you don't wish you could NUC when you need to. And again, in my experience, this applies to all thermals.

    As to battery life, I generally shut down the UTC-x if I am moving a few hundred yards. I keep my helmet mounted thermal(s) up, but since the UTC-x runs on guns that run on tripods, "hip shooting" with the UTC-x would be difficult. Of course there are exceptions. So, I've never tried leaving it running for 6-8 hours continuous use. That said I doubt it would work that long with only 2 c123 batteries. In the summer I would guess maybe 4 hours and in the winter half that. The batteries are easy to change without looking if you practice. But I would say no thermal clipon I've used meets this requirement. The Apollo Pro should meet this requirement, the Zeus Pro does. Those units take 4 x c123 batteries. So 8+ hours in the summer but probably only 4+ in the winter.

    The UTC-x says it meets the "stand alone sight" requirement. But it is a long range thermal clipon, so it uses the "tiny screen" trick. Hence, looking thru the rear of it with no magnification, it is tiny. So, I would consider it to be a thermal spotter or a thermal stand alone sight only in desperation. That is, worse than "marginal". The SNIPE and the APOLLO on the other hand, pass this requirement since they don't use the tiny screen trick.

    The main strength of the UTC-x is that it is a CLIPON. You can move it around from rifle to rifle and it does not shift the POI. That is a combination of the collimating lens on the back and the solid optical train that maintains the optical center thru the entire device. None of the below $10k list price thermal clipons do this. Both the Apollo and the SNIPE have adjustments, that are easy to use. The UTC-x has no adjustments. Mount and shoot. The only caveat to this is that the optical centers must be "in the ball park. Rings that are between 1.3 and 1.4 optical center work with the UTC-x which is 1.31. ADM 1.55 mount does not work, the UTC-x hit low with that mount on the day scope.

    The primary downsides of the UTC-x are availability and price. It took me six months of calling around the country to find an official BAE dealer that would work with me to get approval from BAE to sell one to me. I finally succeeded, but I'm not sure how repeatable the process is.

    Right now, if I was buying another long distance thermal clipon (supports 10x or more magnification on the day scope) ... I would go with the FLIR T-75. Those are available for $11,900. They are easier to get, in fact, the path now is to buy direct from FLIR. I have the name and number of the FLIR person to call if anyone is interested.

  • Some general data on thermal clipons I've learned over the past 4 years of using them ...

    A lot of people think they want a thermal clipon ... I did !!! Night vision clipons and thermal clipons have a significant difference ... the NV clipon is more of an analog device ... whereas the thermal is a digital device. With the thermal you are looking at a TV screen. If you magnify a thermal clipon, on the backend, with either digital magnification or day scope magnification you are looking at a zoomed in TV screen. At 2x a 640x480 becomes a 320x240 and you've lost 75% of your pixels ... that is 75% of your resolution !!! And that is just 2x magnification ... if you go to 4x, then the 640 becomes a 160 and the 480 becomes a 120 ... and you've lost 93% of your resolution.
    For most people that is the limit.
    And that means that for 320 termals 2x is the limit.

    Now thermal scopes don't just magnify with digital, they have magnification on the front end ... on the objective ... like 1.5x or 2x or 3x ... some even 6x ... the Zeus Pro 336, 100mm had 8x on the front.
    And you get your full resolution with thermal scopes with optical magnification on the front end.
    But not with clipons which magnifiy on the backend.

    With most of the civilian thermal clipons ... 4x is the limit for 640s and 2x is the limit for 320s ... you can squeeze up to 6x on the 640s and 3x on the 320s if you can tolerate a fuzzy image. But that is about it.
    With the military clipons you are less fuzzy at 6x and might be able to squeeze 7x or even 8x with some fuzz. That's because the military clipons have better glass, better displays and better software and hence a better image to start with ... and hence a little more magnification can be squeezed before the fuzz becomes intiolerable for most people.

    The exception to this thermal clipon arithemetic are the few "long range" military thermal clipons that support 10x or higher magnification on the back end. How is this possible? They start with a tiny, high quality display. Sort of like a 9 inch high res TV on the other side of the room. You still see the same picture as the 55 inch TV, but the picture is much smaller. When you zoom in on it, you zoom in on the full picture until the full picture fills your screen. And with a high res. display, now you are at like 4x with the UTC-x before the screen is full. From a resolution perspective, you still have all your resolution all the pixels. Then you go to 8x and you are giving up the same resolution you gave up by going to 2x with a full screen thermal clipon. And then you go to 16x at you are at max resolution again. You can squeeze up to 20x but it is fuzzy.
    The FLIR T75, the N-Optics TC-50, the BAE UTC-x are among these "magic" thermal clipons that can support 10x magnification on the day scope. Without one of these you are going to be limited to around 4x for a 640 thermal plus whatever you can tolerate when you try to squeeze it up a bit. People report the LTWS looks good at 6x but gets fuzzy after that. I'd say the SNIPE is the same. Those start with high quality images, so can squeeze more before the fuzz becomes intolerable.

    So once I realized all this, I realized either I wanted one of the 10x+ thermal clipons or I did not want a thermal clipon. I wanted to be able to use my FFP day scope reticle just like it was day time. I set a nominal goal of 900yds ... that seemed more than far enough for night shooting.
    For the IPSC-D steel I use, I think 10x is enough (for me) to get hits at 900yds consitently, wind allowing. And I found those three above that seem to fit the bill. The FLIR T-75s are still available directly from FLIR for $11,900, but I don't know how much longer that will be the case.

    Another aspect of thermal clipons is the quality of the optical train. The ability of the device to retain the optical center all the way thru the device. The higher cost, higher quality military clipons can do this. The lower cost, lower quality civilian clipons cannot. The civilian clipons have menus and buttons to allow you to "adjust" the "boresight" of your thermal clipon, to reduce abs(POI-POA). The military clipons that I have/have had, do not, they are designed to be "real" clipons. They do not adjust.
    All clipons do have a tolerance for how far out of alignment they can be with respect to the optical center of the day scope. Mis-alignment is mostly caused by rings that place the optical center of the day scope at a different height than the optical center of the clipon. This aspect applies to both NV and Thermal clipons. So, you might need new rings to go with that new clipon. In general your rings will be higher if you are using clipons, either NV or thermal. My rings on the 4 rifles that I expect to use my clipons with are between 1.3 and 1.4 because I know my clipons wiill work with those heights. I also have a 1.55 center mount and it will work with the PVS-30 but not with the UTC-x.
    In general thermals are either clipons or scopes. Clipons have collimating lenses on the back that work to preserve the optical centers of the clipon and day scope, even if they are slightly mis-aligned. That collimating lens is what makes them clipons.
    Thermal scopes have diopter adjustable lenses on the back. That feature enables the rear lens to be adjusted for humans with bad eyes like mine. So aagin, clipons have collimating lens on back scopes have diopter adjustable lens on back.

    So what thermal is right for a given application?

    For hunting, most shots are under 350yds and within that most within 200yds and within that most within 100yds. At those distances, we can use the critter as the reticle and most of our cartridges fly fairly flat. So, I would rather have my magnification on the front of the scope so I can have all my resolution for positive ID.

    Only if I want to shoot hot targets out farther, 400-900yds at night do I need a thermal clipon because I want my day scope reticle, so I can hold for wind and elevation or maybe some combination of dailing and holding. And for long distance, I want more magnification that most thermal clipons provide, so I want the long range military thermal clipons.

    Now if you only have one rifle and you don't want to take your day optic off, then a thermal clipon makes sense, and if you only want to shoot out to about 350yds at night and if you have a flat flying cartridge, then a 4x to 6x magnification on the day optic will work for you and you can get either a civilian 640 thermal clipon or a miltary one if you prefer not to adjust your boresight much.
    If you have more than one rifle, I would recommend setting one up for night work and putting a thermal scope on it.

    So for the vast majority of night hunters, I recommend a thermal scope.

    A few might do fine with an NV clipon and a few might do ok with a low end thermal clipon.

    Only long distance night shooters, shooting at hot targets, need a long distance thermal clipon and not many people want to bother with the extra trouble (I heat my steel with a propane torch) or the extra expense (military thermal clipons cost considerably more than civilian thermal scopes).

  • I ended up going with dedicated thermal equipment about a year ago... but these posts are informative. Thank you.


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