TFB Review: ATN ThOR 4 Thermal Scope-Red Hot Optic or Lukewarm Glass?

    A proper daytime target for the ThOR

    The perfect optic for searching for Dutch in Central America-Note how the black adhesive dots show up as "hot" and provide nice aiming points for zeroing

    Bring the heat

    Thermal imaging used to be the exclusive preserve of the military, big businesses, or deep pocketed Law Enforcement departments.  Back when I started shooting, a thermal optic cost tens of thousands of dollars.  In recent years, however, thermal imaging has come down greatly in cost due to advances in cooling, image processing, and digital displays.  The ATN ThOR 4 is coming in between $1999 and $3499 MSRP, depending on lens size.

    Initial Scan

    The ATN ThOR (Which stands for Thermal Optic, Rifle) 4  384×288 4.5-18x sent to us for testing comes with an impressive spec sheet:

    • ATN Obsidian IV Dual Core
    • 1280×720 HD Micro Display
    • 90mm eye relief
    • Video recording resolution of 1280×960 @ 30/60 fps
    • Ballistic Calculator
    • Laser Rangefinder
    • Wifi to link with iOS or Android Obsidian App
    • Bluetooth
    • 3D Gyroscope
    • 3D accelerometer
    • E-Barometer
    • Smart Range Finder
    • Recoil Activated Video
    • Electronic Compass
    • Multiple Color Patterns, Reticle Options, and Reticle Colors
    • Microphone
    • Micro USB-C Charger
    • 30mm rings included
    • 18 Hour Battery Life
    • “Weather Resistant”
    • Dimensions: 13.8″x3″x3″
    • 2.2 lb weight
    • 3-year Warranty
    • MSRP:  $3199.00

    Scanning for Lifeforms

    Getting further into the specs, the ATN ThOR 4 4.5-18x has a 384×288 Sensor, which has some impressive detection ranges.  The “Human Detection Range” is 1800 yards.  ATN claims “Target Recognition” at 720 yards and “Identification” at 430.  This author is unsure of the exact methodology they are using to differentiate between the three detection classes, however.

    Initial Setup

    The scope comes with quite a few accessories. The included rings were quite appreciated.

    The ATN ThOR 4 as it comes in the box

    The ATN ThOR 4 came in a box with a lot of custom foam inserts for various pieces and accessories of this thermal sighting system.  Included were the 30mm rings (with an option to use the L-shaped ring if one has limited rail space), as well as a charging cable, zippered case, and rubber eyecup.  I charged the optic overnight and promptly mounted it on a LaRue Predatar.  This particular rifle had a 51T muzzle brake for use with my AAC Blackout suppressor.  Being that I was planning on doing a lot of night shooting with the optic, a suppressor was the neighborly thing to equip on the rifle.

    Test rig with scope mounted

    My test rig for the ATN ThOR 4: a LaRue Predatar 5.56

    The THOR also comes with an extended mount if one only has a short section of rail.  Testing of the second unit was done with a PRI upper chambered in 6.8×43 (SPC).

    The 30mm mounts went on ok.  All the supplied hardware was easy to properly torque on the first unit.  Upon testing of a second unit, the base screw failed at a very low level of torque. I did not detect any degree of reticle cant when leveling the optic with the rifle.  Eye relief was very forgiving and allowed for some flexibility in how I wanted it mounted on the receiver rails.  Initial tests of the thermal detection capabilities went well indoors and out.  Unfortunately for my lungs, but fortunately for the test, I was able to test the optic in heavy smoke due to a local wildfire.  The smoke did not matter a bit.  I was able to see thermal outlines of cars, houses, etc, as well as wildlife, moving around in the night on a hillside 700 yards away.

    Pushing all the right buttons

    The ATN ThOR 4 has both a nice and easily understandable GUI as well as tactical and easy to use controls.  A 4 button layout on top works well, as well as the zoom knob/scroll wheel on the side.  The front focal ring needs firm pressure to adjust,but stays put under recoil.  The menus, sub-menus, and shortcut icons are easy enough to grasp on the display as well.

    Day at the range

    I initially zeroed and tested the ATN ThOR 4 during the daytime.  The biggest advantage of a thermal optic over IR image intensifying “Night Vision” is that you can use them day or night without a pinhole cover or risk of damaging the sensor array.  ATN recommends using different materials on one’s targets for better visibility due to temperature differences.  I found that white paper targets with black “Shoot-N-See” adhesive dots made for a good combo.  The dots would be hot enough in comparison to the paper in order to stand out as a pretty visible aiming point at 100 yards.

    Don’t try and zero this optic on a regular sheet of paper- the aiming points don’t show up well.

    A proper daytime target for the ThOR

    The perfect optic for searching for Dutch in Central America-Note how the black adhesive dots show up as “hot” and provide nice aiming points for zeroing

    ATN has touted a “One Shot Zero” for the ThOR 4 scope.  The way it is supposed to work is the shooter fires one shot with the reticle in the center of the target. I chose to use 5 shot groups in order to check that there was consistency shot-shot.  After firing my first group, I selected the “zero” function on the sub-menu.  I then moved the reticle up to where the group was.  A useful tool is that a ghost image of one’s original reticle position remains on the screen until you are done entering corrections.  This is an easier process than visually correcting traditional riflescopes in the same manner.  After zeroing, I fired another group and was on target.  In theory, the “one shot zero” works as advertised.

    During my daytime testing, I also found it easy to detect steel targets out to 200 yards. The 3-400 yard targets in deep foliage were difficult to make out, and the 5-800 yard targets were impossible to detect on the sunny, rocky hillside.  Animal body heat stood out, however, with small mammals and birds easy to see moving around out to 300 yards.

    The built in rangefinder is of marginal efficacy.  Given a pre-selected target height, one is supposed to hold an arrow above and then below the target.  Using a custom entry of 18 inches, I measured an 18″ target 3 times at a range of 100 yards, and got results ranging from 101-127 yards.  Results were even more erratic at 300 yards.  It is no replacement for a true rangefinder.

    Shadows Fall

    Suppressor on-gotta be quiet!

    Set for a night shoot

    Returning at night, I brought some of ATN’s suggested targets for range use:  Frozen water bottles.  I had also loaded their Obsidian 4 App onto my phone to test its functionality.  Beginning by setting some water bottles on the 100 yard berm, I taped the rest to targets at various ranges from 50-250y. I was all set for a night shoot.  The water bottles glowed on the display like balls of fire.  Shooting them was a delight, as the ice flying off on impact was visible on screen.  I wish I could upload video of this phenomenon, but the “recoil activated video” function did not work properly (more on this later).

    Frozen water bottle

    A frozen water bottle as viewed through the “Black Hot” scheme at night. Air temps were in the 60’s.

    steel at night

    100 yard steel targets at night

    I had a few other shooters eager to try their hand at the use of the ATN ThOR 4.  We were all successfully detecting and hitting 2″ diameter “zipper” targets within a steel silhouette at 150 yards.  While other shooters were on the gun, I was looking at the Obsidian 4 app on my phone, which allows one to see what the scope is looking at amongst other features.  I noticed that it had the annoying tendency to not display the reticle location properly.  The reticle was always off by a bit when viewed on the app, though on target when viewed through the scope.  The scope also froze twice during testing, requiring a restart.

    Zipper target

    Steel zipper target at night

    Overall, the night shoot went well.  I ended the evening by putting shots on a 500 yard steel silhouette target.  The target was much easier to see at night than during the day, being that the steel was now a significantly different temperature than the rocks or sagebrush surrounding it.  This was a fun and unique thing to do at night in total darkness.  Being sure of one’s target and what lies beyond it was easy as well.  If there were anything living, we would have detected the heat signature.

    500 yard target

    500 yard steel target is the black square to the right of the center of the reticle(Black Hot scheme).-Note how pixellated the image is at high zoom.

    Animal Detection

    I took the ATN ThOR 4 out to an area where I knew I’d see some animal activity.  Right at dusk, I observed a small herd of whitetail deer moving through a meadow at 300 yards.  Viewed through the ThOR 4, they showed up well up to 6x magnification.  Any more than that and they became pixelated blobs.  A cow and calf moose were very visible at 300, but again there was much better imagery at lower magnification.  Moving to within 100 yards of the moose, I got some better imagery but nothing as detailed ATN shows on their website.


    Later that evening, I detected deer feeding up a meadow that was 1200 yards away, as well as multiple nighthawks and bats flying though the air.  The scope was very capable of long range heat detection when it worked, but it froze three times during a night-time walk around my ranch to check on my trail cameras.  The freeze was on a blank screen, and required a hard restart.  This error persisted even after firmware updates.

    Freeze screen

    The freeze screen I would often get-This would be an unpleasant surprise either while hunting game or monitoring a suspect.

    Shortcomings and issues

    Prospective buyers should know that the Achilles heel of most thermal optics is any reflective surface.  Being that the optic works by detecting differentiations in IR signatures, window glass will work like a mirror.  The ATN ThOR 4 also had a very difficult time imaging caves properly from as close as 100 yards, they looked like a blur with no depth.  These issues are shortcoming to many thermal optics, not just the ATN ThOR 4.

    Issues specific to the ThOR 4.

    The display froze multiple times during testing, while using various functions of the scope.  The micro SD card slot has a small gap underneath, where one can lose a card into the scope body if one isn’t careful (I found out the hard way and had to remove the card slot in order to retrieve my card).  Most disappointingly, the recoil activated video feature never recorded anything onto the SD card with the initial firmware.

    Even with a firmware update while testing a second unit, I still got no usable video even though the optic displayed that it was recording!  The zoom was somewhat useless beyond 8x, as anything over that (one can activate up to a 40x zoom using a sub-menu on the scope) becomes extremely pixelated like an 8-bit video game.  The app also needs a lot of work in order to have better functionality.  I also never got the “smart ranging” function to work properly day or night under any conditions.

    The ATN Obsidian App that is supposed to let one view the scope through one’s phone also had a lot of bugs.  It crashes immediately when one tries to view the photo/video gallery.  The viewfinder is also consistently off of where the scope is actually aimed (see photos).  The scope is supposed to connect to one’s phone through either wifi or bluetooth, but the bluetooth function did not work.

    I also conducted a “box drill” at 100y with the ThOR 4 to see how well the corrections tracked.  A “box drill” is conducted by leveling the optic and the target prior to testing.  After firing an initial group, one puts in a sequence of equal corrections down, left, up and right, firing a group each time while aiming at the same point.  If one achieves a perfect square or “box”, the scope is tracking corrections properly.  Unfortunately, the ThOR 4 failed two box drills.  While the elevation corrections tracked properly, the windage corrections did not.  The R-L corrections were off by an inch over 10 clicks, while the L-R were off by 1/2″.

    Failure on the box drill

    Not exactly a perfect box.

    Overall IMpressions

    The ATN ThOR 4 boasts an impressive list of features for an optic.  I can say I’ve never before used an optic that can connect to my phone, and can supposedly auto-post recoil-activated photos and video to social media (should one choose to let it).  The thermal detection was very good, and it makes for a fun experience shooting at night or detecting wildlife in the dark.  That being said, there are unresolved issues with this optic, including freezing, display issues, poorly designed hardware, poor mounting hardware, and some features not working properly.  The corrections not tracking properly are another major shortcoming.

    One example of a bug as of the latest firmware-the reticle wouldn’t center in the screen

    I could see this being a somewhat useful optic in a stationary hunting situation from a ground or tree blind, or from a vehicle.  It would be useful (when operating properly) for nocturnal control of species that are causing damage and depredations such as wild pigs, coyotes or nutria.  I am not convinced of its efficacy or reliability for use in a law enforcement, military or self defense role.

    The bottom line is that for the price, the quality of this unit is wholly unacceptable.  There are other thermal optics out there at similar price points that have a far more proven track record.  One could also get an excellent low-light scope from a top-tier manufacturer for this kind of money.  I would liken the experience to hiring a reluctant teenager for a summer job-It may be “smart”, but though it can post pics and video to social media, it doesn’t work much.  Things may change: The optic is capable of firmware updates, and ATN may someday resolve these issues.  I personally have an older ATN PVS14 night vision unit that has worked just fine for many years, and some of their products can be good.  As things stand right now, the ATN ThOR 4 tries to do a lot of things, yet does few of those things very well.


    • Extremely feature rich
    • Great thermal detection range, even small animals show up well.
    • Offers a color scheme or reticle to satisfy most anyone
    • Holds Zero well
    • Zero function is easy to use
    • Generous eye relief
    • Comes with mounting hardware
    • Fans of the “Predator” series will enjoy the color scheme options.
    • Good physical controls and GUI navigation


    • Freezes
    • Still plagued by bugs
    • Corrections don’t track consistently
    • Rangefinding doesn’t work well
    • Higher levels of zoom are too pixellated
    • Provided mounting hardware is weak
    • SD card functionality needs fixing
    • Doesn’t come with a 3-dot visible laser (Joking)

    For more information, please visit ATN.  (Their page for this scope is very well done and shows a lot of the features quite nicely)

    Thanks to Hughston Shooting School for Rangetime

    Rusty S.

    Having always had a passion for firearms, Rusty S. has had experience in gunsmithing, firearms retail, hunting, competitive shooting, range construction, as an IDPA certified range safety officer and a certified instructor. He has received military, law enforcement, and private training in the use of firearms. He is fortunate enough to have access to class 3 weaponry as well.