How to zero a thermal scope at night or during the day

Zeroing a thermal scope follows the same idea as any riflescope: make the point of aim match where the bullet lands at a known distance. Two things are different. The scope sees heat, not ink, so a normal paper target shows up as a blank square. And there are no turrets; you move the reticle digitally, in a menu. Every step below comes from a maker's manual or support article, linked where it's used. Your own scope's manual wins where it differs.

Safety first: backstop and range rules

How digital zeroing works

On a thermal scope, the reticle is drawn on the screen. Zeroing moves that drawn reticle to where the bullet actually hit, and saves its position in a profile. ATN's ThOR 6 manual describes it as adjusting "the position of the reticle along the X (horizontal) and Y (vertical) axes to align the point of aim with the actual point of impact" ( ATN ThOR 6 manual). Pulsar's zeroing article puts it the same way: X is windage and Y is elevation (Pulsar).

Two features make it easier than it sounds. Freeze frame holds the image after the shot, so you don't have to keep the rifle perfectly still while you move the reticle. And zoom makes each adjustment step finer. Pulsar publishes the click value for the Thermion 2 XQ50 Pro as 13 mm at 100 m at 3x, 6.5 mm at 6x and 3.25 mm at 12x (Pulsar), and ATN's manual says to change magnification during zeroing "for greater precision when aligning the reticle with the impact point." So zoom in before you move the reticle.

What you need

• The scope, mounted properly. Use the mount the maker specifies. ATN's guide says quality thermal scopes "when mounted properly to a torqued Picatinny rail, will hold zero just as reliably as high-end traditional daytime glass."
• A rest that holds the rifle still. ATN lists "a highly stable shooting rest, lead sled, or sandbags (stability is critical for digital zeroing)," and warns that if you're "wobbling off-hand or using a flimsy bipod, this process will not work." Pulsar's manual says "shooting from a benchrest is recommended" ( Pulsar manual).
• The ammunition you hunt with. ATN's guide says to bring "your chosen hunting ammunition (do not zero with cheap plinking ammo)."
• A target at a known distance. Pulsar's manual: "Set a target at a known distance." For hogs, ATN says "a 50-yard or 100-yard zero is ideal."
• A target your thermal can see. Covered in the next section.

The rest is the piece most people underbuy. A clamping tripod that holds the rifle hands-free keeps the aim point steady through the shot and the freeze, and it's the same rest you'd use over a feeder. Our best shooting sticks and tripods covers the options, and our Primos Trigger Stick vs BOG DeathGrip comparison weighs the two most common.

Thermal targets that work

A thermal scope can't see printing. Pulsar explains that because a thermal scope works through infrared, "they can't read the ink printed on paper," so standard targets show up as plain squares (Pulsar). You need something hotter or colder than its background. Options the makers themselves suggest:

• A maker's heated target. ATN lists a "heated target for zeroing" in the box with the ThOR 6 and ThOR 6 Mini (ATN ThOR 6 Mini manual), and Pulsar says it sells dedicated heated targets.
• Hand warmers in a box. AGM suggests cutting "a one-inch square hole on the front face of a cardboard box," taping disposable hand warmers to the inside back panel and aiming through the square, which gives "a crisp aiming point without excess bloom." AGM says it works best at night or in cooler weather (AGM). Pulsar notes that hand warmers taped to a board "will leak once shot."
• Foil or reflective tape. ATN suggests "squares of aluminum foil angled slightly upward to reflect the cold sky." AGM suggests HVAC reflective tape on cardboard: "tilt it toward the sun, and it lights up brilliantly through thermal optics," with bullet holes showing as cold spots. AGM rates it best for daytime sun and less effective in shade or clouds.
• Cold targets. ATN suggests "an ice pack wrapped in duct tape as a 'cold' target" for hot days. Pulsar describes filling bullet holes with screws chilled in a cooler so they show as cold marks; only walk downrange during a cease-fire with the rifle unloaded.
• Duct tape on a light board. Pulsar's budget option: a white backing with target zones of black duct tape, because black absorbs heat.

How to zero a thermal scope, step by step

These steps follow ATN's ThOR 6 manual and zeroing guide and Pulsar's Thermion 2 manual and article. Menu names differ by maker, so match them to your own manual.

1. Set the target at a known distance against a safe backstop. 50 or 100 yards for hogs, per ATN. If your first shot isn't on the target at all, ATN says to "move the target up to 25 yards to get on paper, zero it there, and then move back to 100 yards."
2. Zero in conditions close to how you'll hunt, then focus. Pulsar's manual recommends "zeroing at a temperature close to the riflescope's operating temperature." Pulsar's article has you adjust the eyepiece (diopter) for a sharp display, then the lens focus for a sharp target.
3. Pick the profile and distance. In the zeroing menu, select or create a profile and enter the distance you're zeroing at. ATN: "Select the target distance at which you are performing zeroing." Pulsar lets you set a zeroing distance from 1 to 910 m.
4. Lock the rifle in the rest. Center the reticle on the target. The rifle should hold that aim without you.
5. Fire one careful shot at the center. ATN: "Fire one single, highly controlled shot." (Pulsar's article uses a group instead; see below.)
6. Freeze the image. ATN's manual: "After firing, activate Freeze Frame to lock the display image, then adjust the reticle without worrying about target movement or heat dissipation." On the Thermion 2, Pulsar's article points to the freeze-frame button marked with a snowflake icon.
7. Zoom in. Higher magnification means finer reticle steps, as the click values above show.
8. Move the reticle onto the bullet hole. Use the control wheel or buttons to move the reticle from the aim point to the impact: X for windage, Y for elevation. ATN notes the hole often shows as a warm spot from the bullet's strike.
9. Save. On the Thermion 2, a long press saves and the scope shows "Zeroing coordinates saved." On the ThOR 6, press and hold the control wheel to confirm.
10. Confirm with more shots. Pulsar's manual: "Fire a second shot, now the point of impact and the aiming point must be matched." ATN's guide goes further: fire a 3-shot group at the center, and "all three shots should now cluster directly where you are aiming."
11. Write the numbers down. Note the X/Y coordinates of each saved zero. oneleaf warns that on its Mars scope, "firmware updates will erase all the saved zero profiles and the ballistic profiles" (oneleaf).

One shot or a group?

ATN's method is one shot, freeze, move the reticle to that hole. Pulsar's Thermion 2 article describes a five-shot group at 50 yards, then aiming back at the center of the target, freezing, and moving the reticle over the group, not the target center. Both end the same way: a confirmation group that lands where you aim.

The trade-off is simple. One shot is fast and uses the least ammunition, but it trusts that one shot was a good one. A group averages out the normal spread between shots, so the zero reflects where the rifle really prints. If your first confirmation group doesn't center on the aim point, repeat the process from the group's center.

How to zero a thermal scope during the day

You can. ATN's guide answers the question directly ("Yes, absolutely") but notes the catch: "If you are shooting in the heat of the day, the sun will warm up the backstop, making targets harder to see." Its fixes:

• Use a cold target, such as an ice pack wrapped in duct tape.
• Use foil, which "reflects the ambient temperature of the sky, creating a stark contrast against a warm dirt berm."
• Switch between Black Hot and White Hot to see which gives the best contrast.

AGM's reflective-tape target is built for sunny days, tilted toward the sun, and Pulsar suggests hand warmers or foil "on a hot day." If you have the choice, ATN says zeroing is often easier at night, "because the cooler ambient temperatures provide a starker contrast against heated targets and glowing bullet impacts."

Bore-sighting a new scope first

If the scope is brand new on the rifle, the first shot may miss the target entirely. ATN's guide describes bore-sighting as "optional but helpful": remove the bolt (ATN's guide also covers AR-style rifles), set the rifle in a stable rest, look down the barrel from the chamber end and center it on the target at 25 or 50 yards. Then, without moving the rifle, look through the thermal scope, open the zeroing menu and move the reticle onto the same target. That gets you close enough for the live-fire steps above.

Profiles, remounting and firmware

Most thermal scopes save several zeros. ATN's ThOR 6 manual says profiles let you store "different setups for various rifles, ammunition types, or shooting distances." Pulsar's Thermion 2 XQ50 Pro stores up to 5 zeroing profiles with 10 distances each, and Sightmark says the Wraith Mini thermal's five weapon profiles hold zeros for different weapons (Sightmark). Give each rifle and load its own profile, named so you can't mix them up in the dark.

A few habits keep a zero honest. Confirm it with a shot or two after the scope has been off the rifle, after a change of ammunition, and before the first hunt of a season. Record your X/Y numbers before any firmware update. And confirm at the distance you actually shoot: if your feeder sits at 70 yards, check your 50- or 100-yard zero there.

Still choosing a scope? Our best thermal scopes under $1,000 and best thermal scopes for hog hunting note which ones publish zero profiles and freeze-frame zeroing, and our 256 vs 384 vs 640 guide explains how far each sensor size can identify a hog. Before you shoot at night, read whether you can hunt hogs at night in Texas. More on the category is on the thermal and night vision hub.