Burris BTS 50, thermal riflescope. A contemporary example of just how far technology has come to aid hunters in the eradication of feral animals.

Feral Game Hunters perform an invaluable service to our community, economy, native animals, farmers and agriculturists. The eradication of feral pests by hunters does not draw on the public purse. In fact, hunters directly contribute to the economy through their discretionary spending on travel, vehicles, hunting equipment and accessories, and most importantly; by making a positive contribution to the reduction of feral animal numbers.

As the human population of Australia steadily increases, the maintenance of food production by farmers and agriculturalists is perhaps more important than it ever was. Feral animals are a constant threat to crops and livestock, and traditional day and night-time hunting techniques are in some cases not sufficient to effectively reduce their numbers. Can technology help ethical hunters in their quest to even the odds? I think so.

Night Vision and Thermal Imaging, are they the same thing?

We often hear the terms Night Vision and Thermal Vision used interchangeably however, there are distinct differences between them. To understand this, let’s briefly review the evolution of night vision.

Technology for seeing in the dark was invented in 1935 by German company Allgemeine Elektricitäts-Gesellschaft AG, better known as AEG. At the time, they specialised in the design and manufacture of electrical equipment for industry. AEG night vision devices first went into service with the German military shortly before the start of World War Two in 1939.

The US military had also developed their own “see in the dark” technology. It is important to note that both sides developed their systems using intensifier tubes that processed infrared light. The devices relied upon an active IR generator to “light up” the area under observation. Infrared light is invisible to the human eye unless you are looking through an IR scope, monocular or binocular. The technology was called Night Vision and that name has become synonymous with active IR “see in the dark” devices such as monoculars and binoculars, as well as thermal imaging devices. However, there is a clear distinction between the two.

Thermal imaging does not rely on ambient light, active IR generation, or delicate intensifier tubes. Thermal imaging devices such as riflescopes, binoculars and monoculars, incorporate internal IR scanners that when looked through, measure the heat signatures of objects seen in the viewfinder.

Night Vision devices enable us to see in the dark to a degree, but they don’t “see through” foliage and therefore, don’t overcome nature’s ability to hide feral game in the bush. Thermal imaging on the other hand, helps us to distinguish game even when it is looking away from us and behind foliage in deep scrub. What the naked eye in daylight can’t see, so to at night the same handicap is there with night vision. Not so with thermal imaging, which translates even the tiniest temperature variations into objects that we can see on displays in thermal imaging devices.

Steiner Nighthunter H35, thermal imaging monocular, draws upon Steiner’s heritage of Military and Law Enforcement thermal imaging research and development. The monocular provides hunters with a robust, lightweight and technologically advanced thermal monocular that compliments rifle mounted thermal sights. The ability to scan pitch black forest, bush, clearings, crops and open pasture, and visually locate and distinguish feral game from livestock, makes the unit an asset to any night-time hunter wishing to increase his or her tally of invasive feral game.

How does a thermal imaging riflescope work?

Thermal imaging devices such as riflescopes, binoculars and monoculars, operate on the principle of detecting and measuring differences in infrared radiation (IR). They display recognisable and varying heat signatures in an integrated viewfinder.

The fundamental source of IR is energy, and in this context, we mean thermal radiation. Anything which has a temperature radiates energy in the infrared spectrum. This fundamental applies not only to warm objects but also to cold ones. Everything has a temperature, even the surface of a frozen lake because all objects emit infrared radiation. As an object increases in warmth, so too does its emission of IR.

Thermal imaging devices convert IR thermal energy into something we can see when otherwise we would see nothing. Heat signatures of objects being viewed are compared to other objects around them and are translated into an image on the viewfinder. Higher temperatures (heat signatures) appear brighter and are interpreted by our eyes as recognisable objects. Add to this the features and benefits provided by embedded microchips, and very quickly the advantages of thermal riflescopes overnight vision riflescopes are readily apparent. Thermal imaging riflescopes can also be used very effectively in daylight, not so for night vision devices.

Your first thermal imaging riflescope.

Generally speaking, when there is hunting pressure, feral animals make greater use of the cover of darkness for foraging and feeding. By enabling the hunter to operate more effectively in feral animals’ preferred domain, we can increase the likelihood of greater tallies.

So where do you start if you want to embrace thermal imaging to assist your ethical culling of feral game animals? Do you start with a thermal riflescope or some type of thermal attachment that connects to the objective lens of your daylight scope? And what about binoculars? You already know that your daylight binoculars, no matter how good they are, don’t enable glassing for game in the dark?

Why not combine a thermal imaging monocular with your daylight scope?

Burris ClipOn Thermal

Burris BTC 30 & BTC 50 thermal imaging monocular offer the best of both worlds by combining a hand-held thermal monocular with an optional clip-on adapter that lets you turn your daylight scope into a night-time thermal riflescope.

Burris recognise that some hunters, wanting to embrace thermal imaging technology for the first time, may not want to dedicate a rifle to night-time hunting only. After all, if your favourite deer rifle and daytime scope package could also double as a night-time feral pig-culling rig, then why not?

Burris offer two such thermal imaging monocular’s that address this requirement. Their BTC35 and BTC50 thermal monocular’s can serve double duty as both a hand-held device for thermal scanning for feral animals in the dark, and with the addition of their optional “clip-on” attachment, can be easily fastened over the end of the objective bell on a daylight scope enabling you to add thermal imaging capability to your rifle without changing your scope. The cost-benefit is obvious.

Both the BTC35 and BTC50 monocular have 4 power digital zoom and 4 colour palettes to cater for various scanning situations from forest to open pasture. Burris thermal monocular includes WI-FI to mobile recording capability.

Dedicated Thermal Riflescopes

Burris Thermal riflescope

Burris BTS 35 Thermal riflescope. Just like its big brother the BTS 50, the riflescope mounts to a 1913 Picatinny rail and can store up to 6 separate zero calibrations, making it, once zero calibrated for each rifle, usable on up to 6 separate rifles just by removing from one rifle, fastening to the pic rail of the next rifle, and selecting the corresponding zero calibration from the intuitive menu. All menu options and settings are displayed in the viewfinder and navigation through the menus is controlled by simple, finger-operated controls on the outside of the riflescope body.

Burris currently offer two dedicated thermal riflescopes, and thankfully, they both mount on a 1913 Picatinny rail and can save up to 6 separate zero coordinates. I say thankfully because there is a hidden advantage with better thermal riflescopes and Burris have it. The hidden advantage is the ability to set multiple zero points that enable a hunter to run the unit on up to six different rifles by simply remounting and selecting the appropriate zero setting for that rifle. Or, run up to 6 different loads and select the corresponding zero, or mix and match loads and corresponding zero marks between rifles.

Calibrating Burris thermal riflescopes couldn’t be easier. You don’t need any technical expertise because the whole setup is menu-driven and intuitive. By default, the zero distance is set at 100 metres, but you can override that to match your own preference. I won’t go into all the features and settings here, suffice to say there are 10 different reticle selections, 4 colour palettes, automatic and manual thermal sensor calibration options, brightness adjustment, picture in picture and more.

How easy is it to sight in a thermal riflescope?

Another advantage of thermal riflescopes is the ability to zero your rifle with only one shot. Yes, that’s right, just one shot to zero. After mounting your thermal riflescope, head to the range and place your target at 100 metres.

For thermal riflescopes, I like to use my homemade “thermal target board” which consists of a 1200mm-by-1200mm section of non-structural plywood that is 6 mm thick. I tape large squares of aluminium kitchen foil to the board and over the foil I stick 300mm by 10mm crosses of adhesive PVC electrical tape. The vertical and horizontal lines stand out clearly in daylight when seen through the viewfinder of a thermal riflescope. I use the intersecting PVC tape lines on the target board as my point of aim. It really helps to angle the board back about 25 degrees to increase the heat signature and contrast between the aluminium foil and PVC aiming point.

From the bench, make ready and aim by positioning your thermal riflescope crosshair over the white PVC crosshair on the target board. Fire a shot and note in the viewfinder where it prints on the target. For example, if the shot prints 30mm left and 50mm low, simply adjust the digital reticle in the viewfinder and move it to where the shot landed and save the setting. Fire another shot to confirm. If you made your adjustments correctly, you should be right on the money.

Thermal Monoculars

Burris Hanheld Thermal

Burris currently offer three, dedicated, hand-held, thermal monocular’s, the BTH 25, BTH 35 and BTH 50. All units operate the same, with the only differences being their different focal lengths, zoom rates, visual angle and weight. All three pack a powerhouse of features, including Wi-Fi to remote operation from your smartphone, video and photo recording to an onboard micro-SD card, hot tracking, external HDMI display and more.

Back in the day as a young boy, I accompanied my dad on many unforgettable bunny hunts. I would always want to carry his binoculars, at least until he saw that I was buckling under the weight. When that happened, he would most graciously ask if he could borrow them back for five while he glassed around the paddocks looking for the main ingredient of that evening’s rabbit stew. Those beautiful memories are from a time long ago, but they illustrate an important point, whether we are looking for game animals in the day or the night, the ability to see into the distance and distinguish our quarry, can often make the difference between success and failure. And this is where a thermal monocular or binocular makes all the difference, especially at night.

Thermal monoculars weigh less than thermal binoculars and weight is important on a hunt when you are the one that carries it. There will most likely be many campfire discussions about thermal “binos” versus thermal “monos” for a long time to come, but for me, weight and bulk are critical factors, especially when I’m carrying the load.

Burris Thermal Handheld App for iOS and Android

I want to make mention again the benefits provided by embedded microchips in thermal imaging devices. They shouldn’t be overlooked when considering thermal imaging hunting accessories. Burris certainly have not overlooked them; they have a smartphone app for their handheld thermal imagers. The app greatly enhances your user experience.

After downloading the app from either the Apple App Store or Google Play Store, simply connect your Burris handheld thermal imager to your smartphone or tablet for remote control. Remote features include taking pictures, recording videos, and, controlling image settings such as colour palettes in real-time. Photo and video galleries are easily viewed and transferred to social media networks for sharing.


Thermal imaging technology provides a significant advantage to the ethical hunter in his or her pursuit of feral game. They most definitely do not replace the need to be stealthy, quiet and mindful of the wind. Nor do they negate the need to be observant of the terrain, and dedication to the practice of bona fide hunting craft. Thermal imaging riflescopes, monoculars and binoculars do not make hunting at night easier, but they absolutely do improve the odds.

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