If you’re a hunter or shooter who operates in low light, you might be wondering, can you use a thermal monocular with a scope? The short answer is yes, but it’s not as simple as just holding one in front of the other. This setup is a powerful tool for target identification and observation, but understanding how and when to use it correctly is key to its effectiveness.
Thermal monoculars detect heat signatures, making them perfect for spotting game or people in total darkness, through light fog, or in dense brush. They are handheld devices. Your rifle scope, on the other hand, is a magnified optical sight designed for precise aiming. Using them together bridges the gap between finding a target and accurately engaging it.
Can You Use a Thermal Monocular With a Scope
This method, often called “piggybacking” or “clip-on” use, involves placing the thermal monocular in front of your day scope’s objective lens. The thermal device acts as an external sensor, converting the heat image into a visible one that your regular scope can then magnify. You look through your standard rifle scope and see a thermal picture instead of a normal daytime view.
How the Setup Actually Works
Think of your thermal monocular as a specialized camera. It captures infrared light (heat) and processes it into a video image on its display screen. When you align it perfectly in front of your scope, that video image is projected through the scope’s lenses. Your eye, looking through the scope’s eyepiece, sees that thermal video image, now with the benefit of your scope’s magnification and reticle.
- The thermal does the detecting.
- Your scope does the magnifying and provides the aiming point.
- Your job is to ensure they are lined up correctly.
Step-by-Step Guide to Aligning Your Thermal and Scope
For this to work, you need a stable mounting solution. Here’s how to get started:
- Choose a Mount: You’ll need a specific picatinny or weaver mount that attaches to your rifle’s rail and holds the thermal monocular securely in front of your scope. Don’t rely on hand-holding; it’s not stable enough.
- Mount the Thermal: Attach the monocular to the mount and secure the entire assembly onto your rifle’s forward rail section. Ensure it’s positioned so the monocular’s lens is centered with the scope’s objective lens.
- Bore Sight for Coarse Alignment: Turn on the thermal. With your rifle securely on a rest, look through your scope. You should see the thermal image. Adjust the mount’s windage and elevation knobs to roughly center the thermal picture in your scope’s field of view.
- Zero the System (Critical Step): This is the most important part. You must zero your rifle with the thermal attached. The thermal’s display and the mount’s position will introduce a point of impact shift.
- Set up a target with a distinct heat signature (a small hand warmer works).
- Aim at the target’s center using your scope’s reticle on the thermal image.
- Fire a shot.
- Without moving the rifle, use your scope’s turrets to move the reticle onto the bullet hole you see in the thermal image (the hot impact point may be visible).
- Fire again to confirm zero. Repeat until your point of aim matches point of impact.
Major Advantages of This Method
- Cost-Effective: It’s often cheaper than buying a dedicated thermal riflescope.
- Dual-Use Gear: You can detach the thermal monocular and use it as a handheld scanner, then quickly remount it for shooting.
- Utilizes Existing Optics: You don’t have to change your familiar daytime scope setup or re-zero your primary optic.
Significant Limitations and Challenges
It’s not a perfect system. Being aware of the drawbacks will help you decide if it’s right for you.
- Added Weight and Bulk: It makes your rifle heavier and more front-heavy, which can effect balance and handling.
- Eye Relief Change: The extra device can sometimes alter the eye relief of your scope, forcing you to adjust your cheek weld.
- Image Quality: You are viewing a screen through lenses. The image might not be as crisp as a direct-view thermal scope, and resolution can vary.
- Parallax Issues: If the thermal isn’t perfectly aligned, parallax error can cause aiming inaccuracies, especially at different ranges.
- Battery Dependence: You now have two electronic devices to manage (scope illumination and thermal).
When This Combo Shines
This setup is excellent for specific situations. It’s ideal for hunters who need to scan large areas from a stationary position, like a blind or a truck, then take a shot without switching devices. It’s also great for pest control where long observation periods are followed by a quick shot. The ability to scan without shouldering the rifle reduces fatigue.
When a Dedicated Thermal Scope is Better
For dynamic shooting, moving through terrain, or quick reaction shots, a dedicated thermal riflescope is superior. It’s one integrated unit, lighter, faster to use, and generally offers better image clarity and a more natural shooting experience. If your budget allows and thermal is your primary hunting method, a dedicated scope is the way to go.
Essential Tips for Success
- Practice mounting and dismounting the thermal quickly and consistently.
- Always check your zero before a hunt, as mounting and unmounting can sometimes shift it.
- Understand your thermal’s display settings (like color palettes and brightness) to get the best picture through your scope.
- Start with larger targets at closer ranges to get comfortable with the system before taking longer shots.
So, can you use a thermal monocular with a scope? Absolutely. It’s a versatile and practical approach for many shooters. It requires an investment in a good mount and patience during the zeroing process, but it unlocks a powerful nighttime capability without completely replacing your trusted daytime optic. Just be aware of its limitations and practice regularly to make the most of this hybrid system.
FAQ: Thermal Monoculars and Scopes
Can I use any thermal monocular with my rifle scope?
Most modern thermal monoculars can be used this way, but you must have the correct mounting system. Check the manufacturer’s website for specific rifle mount accessories for your monocular model. Not all have them available.
Does using a thermal monocular affect my daytime scope zero?
If you remove the thermal monocular and its mount, your daytime scope should return to it’s original zero, assuming it was securely mounted and not disturbed. However, it’s always a good practice to confirm your zero after changing any setup on your rifle.
What’s the difference between a clip-on thermal and a handheld monocular used this way?
A dedicated “clip-on” thermal is designed specifically for this purpose, often with features to minimize parallax and optimize the image for use with magnified scopes. Using a standard handheld monocular can work, but it may have more compromises in image alignment and eye relief.
How far can I shoot accurately with a thermal monocular and scope combo?
Effective range depends heavily on the resolution and sensor quality of your thermal, the magnification of your scope, and your ability to maintain a good zero. For most mid-range thermal units, ethical shot distances on medium-sized game are often limited to 200 yards or less, but higher-end models can extend that significantly.