How does the ATN Mars 4 Smart HD Thermal riflescope compare with the current market leaders? Chris Parkin gets stuck into this detailed review to find out!


PROS: Absolute NO.1 issue is the familiar ergonomics and 30mm maintube; Hassle free zeroing; I like the zoom dial on the left side as its quick to apply; Clear menu structure on screen with minimal eyestrain from better `optics` in the eyepiece; Long battery life

CONS: Digital compass was intermittent but of no real use to me; Needs charging outside of your gun cabinet

VERDICT: I went into this test with my sceptical radar on high alert but came away wanting to use the Mars, not just having to review it. It cannot be stated how strongly the ergonomic similarities to daytime scopes make the unit easier to live with on a sporting rifle. Multiple colour pallettes, reticle options and overall rifle setups can be saved in the menu system and all will be covered in due time as the complexity and capability would be dishonoured by skimming over it.

RRP: £3,649

CONTACT: Highland Outdoors 01858 880 491

Thanks for copious amounts of test ammunition used...

Sako 55gr Gamehead Varmint GMK 01489 579999

Hornady Superformance 75gr Varmint V-Max and Superformance SST Edgar Brothers 01625 613177


The ATN brand has had a slightly tough time in the UK due to poor customer reviews and service received in the past, both here and across the globe. And in the era of social media, buyers can vent their frustrations far and wide. Customers paying high prices for high-tech equipment won't tolerate anything but top-quality sales support... and quite right too.

In January this year, the brand was picked up by Highland Outdoors. The cynic in me was keen to see what would change and either disappoint or impress me with this seismic shift. An X-Sight 4K with the latest updated firmware was sent to me, but it was slightly overshadowed (no pun intended) by its thermal big brother, the Mars 4. Discussions with Highland Outdoors informed me of their massive push on this brand and their desire to show it as what it is: an innovative manufacturer producing some of the latest technology available to the shooting market in night vision and thermal imaging.

I have an ungodly (pun intended) incapability of remembering names, especially across multicultural mythological realms, but the Mars 4 looks like an identical twin to the X-Sight, except for a glistening silvery sheen to the 47mm objective lens. Moving rearward, this is surrounded by a familiar adjustable objective type arrangement for image focus that's easy to reach, grip and rotate.

A slightly larger than normal cuboid saddle carries five buttons on top and twin data ports to the right side - one for the supplied USB-C charging cable, the other for a Micro-SD card.

The left side, where one would often expect a parallax dial, is home to the magnification adjustment, all done digitally from 4.4-18x beyond the baseline 4.5x objective lens. This is followed with a large collar on the ocular body that focuses the internal image screen, which is a noticeable crisp realm from edge to edge.

Right at the back is a threaded rim to the ocular lens, enabling the screw fitting of an 85mm-long concertinaed rubber eye shield to dismiss glare from external daylight or reflection onto your otherwise silhouetted image in darkness, away from the eyes of your quarry.

The critically so-far-unmentioned part is that, with a 30mm body tube either side of the saddle, it fits into normal scope rings and, with general overall proportions, as well as 90mm of eye relief, it closely matches the commonly found ergonomics of a conventional riflescope. After four weeks in use, I cannot stress how crucial this is to the product's ease of use!

Mounts for a Weaver/Picatinny rail are supplied, which are, in fairness, far too high for a conventional bolt-action sporting rifle but may well suit a flat-topped AR-15 with extended rail, so fair is fair (the home market for this sight is the good ol' US of A).

Aside from that, I used a set of Warne QD rings that were handy and retained a low shooting position, familiar to me on any of the rifles I tested it with. It first went on a Howa .243, then a Mauser M18 .243 and finally onto my own Rem 700 .223 - all shod with Picatinny rails, I admit, but return to zero was reliable when swapped on and off rifles using quick-release mechanisms.

The Rem 700 is a short action and, when viewed laterally, the rings are spaced equivalent to the action bridges of the bare rifle, so there shouldn't be any issues when mounting to other actions where locating the scope rings is more limited.

The next step is to zero. For thermal scopes, I use a disposable handwarmer to aim at on a clean target to spot bullet splash, or taped to the back of a steel plate. I had casually used the Mars as a thermal spotter straight after arrival so knew the approximate image quality and thermal sensitivity in daylight was pretty good, spying crows up in the tree 300m from my armoury with no problem at all.

The large 10-12" Birchwood Casey Shoot-n-C targets on a white backer were warming enough in sunlight to give me an assured aim point on their own, so the handwarmer wasn't needed. I had slipped an SD card into the Mars and left it on charge overnight. The battery is rated to last 16 hours from a six-hour full charge and I found this to be an honest figure in the 0-10°C day/night temperatures out shooting or in storage.

The battery is internal, so charging can be an issue, but the video, data and photographic storage is on the removable SD card, which is handy when downloading footage to your computer. The onboard screen has an adjustable, automatic timed shut-off with immediate return to use and, in honesty, became what I would term a 'boring' product - but in a good way! It simply worked without much conscious thought needed.

On a new product with multiple features, I intend on living with the Mars and reporting back on the plethora of on-board functions like Stadiametric rangefinder, ballistic computer, recoil-activated video, etc as time goes by. I think the critical matters to cover are immediate capability and ease of set-up to use the basic functions.

Pressing the power button leads to a 10-second warm up before the image stabilises and reticle pops into view. This might sound slower, but the flip side of that 'sturdy' battery life is that you don't need to turn it off or power the screen down, so I never minded with all running automatically in the background. A typical four-hour trip out with auto shutdown, yet immediate screen refresh, never saw the internal indicator dip below a half measure. Any kind of USB charge bank you may have for a phone or tablet is compatible with the Mars so you are unlikely to ever be short of power; ATN offer one in their range as well.

You can choose how complex you want the image screen to be with regularly used functions first to hand, so a single press on the central 'OK' button reveals bright red icons on a laterally sliding menu that are clear to the eye.

Two clicks on the left button takes you into the zeroing menu with X and Y axis values displayed for your records. It's a moving reticle system for zeroing so when you have fired your first round, move the reticle up/down/left/right to the impact point and press OK to either save the new figures or go back. The magnification dial is still enabled through this process, and makes the click values effectively change sizes as the magnification is changed for more speed or more zeroing precision.

Visibility is good and, thanks to the conventional shooting position with five buttons and the rotating magnification dial, I found it fast and intuitive to make changes to my primary zero. It should be noted that residual heat was seen at 100m from the bullet's passage through 6mm plywood target board for 10-15 seconds. I will be using inch-thick ply in the future as it makes the mark last longer with a higher generated energy transfer. I had a spotting scope on hand, but the thicker board would make life still easier with a direct hotspot to place the moving reticle onto.

At this point, I will pause as the gun is now on target at 100m, zeroed 5cm high to give me a decent point-blank zero on my likely quarry out to 200m. As with any thermal, quarry has no indication it is being watched or spooked so time is on your hands when considering shots. It is a totally different visual world to enter, but with familiar ergonomics and feel, even with the concertinaed rubber eye shield on or off, you are immediately shooting, in essence, the same rifle and optics as you do in daylight. I have listed do's and don'ts with thermal many times before and all of these apply.

The Mars has Bluetooth and wifi to pair up and transfer data to the Obsidian app, but all images seen here are from on-board video. In daylight, the Mars shows a good picture with a decent level of topography and foliage as well as fence lines etc.

Field of view is generous on low magnification, but will obviously retreat inward as the magnification is dialled upward on the left-side dial. I found 4.5-10x magnification more than capable and only tended to wind the zoom up if tackling smaller, distant targets where aim needed greater precision.

Movement of the reticle in your field of view when zooming is clear, but a point to note for the cautious is that it remains locked in relation to the image picture; you are NOT losing zero and will get used to the fact it looks like it's having a jumping spell as you wind the mag on and off. The image is obviously grainy and pixelated compared to a daylight optic, growing more so as the zoom is built up, but this is par for the course with thermal electronics.

Remaining in the lower half of the magnification range relies on the optical magnification from the lens more than just zoomed digitisation of the internal screen, which showed a decent eye box without critical pinpoint focal areas as some devices show.

A compass spans the top half with an inclinometer on the right side for up and downhill on display. There are also cant/roll sensors to display any unwanted lean you may have applied to the rifle.

This Mars has the 1280x720 HD internal display projecting from the 384x388 sensor, and a 640 sensor option will soon be available in slightly different magnification specifications for cleaner image quality, but at a £2,000 price increase.

The Mars 4 has definitely got me hooked - I want to learn more about it, push its limits and pass this on to you. And for all those who have read the comments made online about the ATN X-Sight, the Mars I am using has categorically never crashed or lost zero on rabbits under 250m and foxes out to 350m.

Confidently engaged with a .223 rifle, I can casually lift this from the cabinet, knowing that, more than likely, the battery will still be half charged or better after the last time it was dumped back in at 2:30am from the previous week's trip out.