How to Use a Thermal Add-On Adapter with Your Existing Rifle Scope

You've spent years finding the perfect daytime riflescope — the right magnification, the right reticle, zeroed exactly where you want it. Our add-on adapter lets you keep all of that and simply add thermal capability when the sun goes down. Here's how it works and what to expect.

What Is a Night Pearl Thermal Add-On Adapter?

Our adapter allows you to use any thermal add-on device that mounts in front of your existing riflescope's objective lens. It intercepts the image before it enters your scope, overlaying a thermal picture onto your standard view. Your zero stays intact. Your reticle stays in place. You've simply added thermal imaging to a scope you already trust.

Why Use a Night Pearl Add-On Instead of a Dedicated Thermal Scope?

Three reasons: cost, flexibility, and zero retention.

• Cost: A quality add-on device is significantly less expensive than buying a full dedicated thermal riflescope at the same performance level — particularly valuable if you own more than one rifle.
• Flexibility: One add-on device can move between multiple rifles and scopes. Buy once, use everywhere — you simply need to choose the correct adapter for each scope.
• Zero retention: Because you're not changing your scope, your zero never moves. Mount the add-on, hunt, remove it — your daylight zero is exactly where you left it.*

Compatibility: What Scopes Work?

Most other add-on adapters on the market are designed for scopes with objective lenses between 40mm and 56mm, and they come with a range of adaptor rings to fit the most common objective lens diameters.
NIGHT PEARL DOES IT DIFFERENTLY

In our experience, to maintain 100% accuracy and preserve your scope's zero, you should buy an adapter that fits your scope perfectly. Avoid universal solutions. Check your scope's objective size (usually printed on the scope — e.g., 3-12x50 indicates a 50mm objective lens) before ordering. Use a caliper to measure the outer diameter of your scope's objective bell. That measurement tells you which adapter size to order. For example, a 3-12x50 scope typically requires an adapter in the 56mm, 57mm or 58mm range, depending on the bell's outer diameter.

Key tip: set your daytime scope to its lowest magnification when using an add-on. This gives you the widest field of view and the cleanest thermal image transfer.

Step-by-Step: Mounting the Add-On

1. Select the correct adapter ring for your scope's outer objective diameter.
2. Thread the adapter ring onto the add-on unit.
3. Slide the add-on onto the objective end of your riflescope and tighten.
4. Power on the add-on and rotate the display to a position that suits your eye.
5. Set your scope magnification to its lowest level for the best performance.
6. You're ready to hunt.

Image Quality Tips

Thermal add-ons work best at lower scope magnifications — typically 1x–4x. Higher magnification can cause vignetting (dark edges) or reduce image quality. Sensor resolution also matters: Night Pearl add-ons use 384×288px and 640×512px sensors, giving you a sharp, detailed image even through your scope's eyepiece.

Is a Thermal Add-On Right for You?

A thermal add-on is the ideal solution if you already own a quality riflescope and want to add thermal capability without starting over. It's especially popular among deer stalkers who hunt with a rifle in daylight and want to extend their season into the legal shooting hours before dawn and after dusk.

See Night Pearl's add-on adapter lineup and find the right fit for your setup at https://nightpearluk.com/collections/add-on.

* The Night Pearl team guarantees this performance with Night Pearl products; we cannot guarantee the same performance with other brands.