Athlon Optics Cronus ATS Pro 35L-400 Thermal Scope with LRF

The Athlon Cronus ATS Pro 35L-400 is a thermal riflescope that Athlon says "retains the appearance of a traditional daylight scope": a 30 mm tube, a focus ring that acts like a parallax adjustment and first focal plane reticles, built around a 400 × 300, 12 μm sensor, a laser rangefinder rated to 1,600 yards and a ballistic calculator that can put the holdover point on the reticle. Guide's TU435L 3.0 pairs the same sensor size and a 35 mm F1.0 lens with a laser rated to 1,500 m (1,630 yd), and it is rated more sensitive (≤20 mK against ≤25 mK), weighs 27.5 oz against 41.3 and costs less. The 35L-400 answers with a lower 3.3x starting magnification, a wider and taller field of view (7.8° × 5.9° against 7.4° × 4.4°) and Athlon's rating of 10 hours or more on its three batteries, against Guide's rating of over 7 hours.

Key Features

• Range, then hold. In single ranging mode, a short press of the zoom knob measures the distance and, with the ballistic calculator switched on, puts the bullet drop holdover point for that distance on the reticle. Continuous ranging (5, 10 or 20 seconds) shows the holdover in MOA or MIL instead, and Shooting via PIP moves the reticle into the picture-in-picture window. A stadiametric rangefinder is built in as well.

• Ballistics from the app. You build rifle and bullet profiles in the Athlon Ballistics app, which Athlon says covers common calibers and cartridges as well as custom loads, and send them to the scope over its Wi-Fi.

• First focal plane reticles. Athlon's reticle manual lists ten interchangeable reticles for the 35L-400, five MOA and five MIL, on the first focal plane, so their subtensions hold at every zoom step. Each comes in six colors with ten brightness levels.
• Ten zeroing profiles and One Shot Zero. Profiles A to J each save a zero distance (50, 100, 200, 300 or 500 yards or meters), the zero point and the reticle settings, which Athlon says makes it convenient to switch between rifles of different calibers. One Shot Zero freezes the image after a shot and moves the reticle onto the point of impact, one pixel per step of the menu knob.
• Zoom and image tools. Digital zoom takes the 3.3x base magnification to 13.2x in 0.1x steps. Hot track marks the warmest point in view, picture-in-picture sits at the top left, middle or right, and three scene modes (Natural, Enhanced, Highlight) work with seven color palettes.

• A ≤25 mK sensor. Athlon says its lower NETD ratings let the sensor "differentiate smaller temperature fluctuations", and its chart sets a 25 mK image beside an 80 mK one.

• Auto-Shot recording with sound. Switched on, Auto-Shot records a video from 3 seconds before a shot to 7 seconds after, plus five images, with trigger sensitivity in five settings. With the microphone on, videos record sound. 128 GB of built-in storage holds the files, and the USB-C port transfers them to a computer.
• Three batteries. One built-in battery and two external packs. The scope draws on the external pack first, and the USB-C port can run it from a power bank and charges both batteries. Keep the internal battery charged: if it is completely flat, the scope will not start on the external battery alone.
• Wi-Fi and video out. 2.4 GHz Wi-Fi streams live video to the Athlon Thermal app with the phone within about 15 yards, and the micro HDMI port, its cable in the box, feeds an external monitor.

• Sealed for weather. IP67 and fog proof, rated to work from -22°F to 122°F, on external power below -4°F.

Who It's For

• Predator and varmint hunters, the uses Athlon names for it, who want detection, ranging, holdover and recording in one riflescope. Athlon rates its detection range at 2,620 yards and its recognition range at 1,090 yards.
• Choosing within the Cronus ATS Pro line. The Cronus ATS Pro 35-400 has this scope's sensor, lens, display and zoom range without the laser (Athlon lists stadiametric ranging), weighs 37.4 oz and costs less. The 35P-400 is a different design: no tube, a Picatinny mount of its own, a 1024 × 768 display, five zeroing profiles, no laser and 19.7 oz. The 50L-640 shares this scope's manual, controls and 1,600-yard rangefinder and moves to a 640 × 480 sensor behind a 50 mm lens, zooming to 23.6x, at 42.3 oz.
• Cross-shopping 35 mm rangefinder scopes. Besides the Guide TU435L 3.0, Alpen's Apex 640 LRF 35mm has a 640 × 512 sensor rated ≤20 mK and a wider 12.4° × 10° field, weighs 608 g, runs up to 15 hours on two batteries and costs less. The 35L-400 gives you 128 GB of storage to its 32 GB and ten zeroing profiles to its five.

Accessories & Compatibility

• Mounting. Two Picatinny-compatible 30 mm rings come in the box; Athlon does not publish their height. The spec sheet's drawing gives the tube 1.3 inches of length ahead of the turret housing and 1.9 inches behind it.