Guide TU635S Thermal Scope

The Guide TU635S Thermal Scope gives you the same 640 × 512 imaging core and 1800 m detection range as the rangefinding model, at a lower price for shooters who already know their ground and their holds. It is a medium to long range scope built around a 35 mm lens, and it comes with a quick release scope mount so it can move between rifles. If you shoot the same paddocks week after week and range by landmark, this is the sensible buy.

Reach to 1800 metres on a 35 mm lens

Detection runs to 1800 m, so you pick up a heat signature well before you have any hope of identifying it, then close the gap with magnification. The zoom range is 2.8x to 22.4x, with a field of view of 11.8° × 7.1°, or 21 m × 12 m at 100 m. Scan at the base setting to catch movement across a fence line, then wind up the magnification once you have something worth looking at.

Fine temperature separation when the ground goes cold

The detector is 640 × 512 at a 12 µm pixel pitch with NETD of 15 mK. NETD describes how small a temperature difference the sensor can resolve, and a lower figure keeps an animal visible in the small hours when the ground has cooled and the contrast between hide and grass has narrowed to almost nothing. The 8 to 14 µm response waveband and 50 Hz frame rate keep the image steady while you track, and the 0.49 inch AMOLED display at 1920 × 1080 puts that detail in front of your eye. Seven palettes are selectable, and the shutterless design removes the recalibration pause.

Weather, batteries and mounting

Run time is 8 hours from two built-in 18650 cells plus one external 18650, and USB-C means you can top it up from the ute or a power bank between sits. The scope is rated IP68 and operates from -20°C to 50°C. At 745 g and 374 × 89 × 76 mm it is the lighter and shorter of the 35 mm pair, which is worth something on a rifle you carry all night. Diopter adjusts -5 to +5. Video and audio recording and a dual-band Wi-Fi hotspot are included for reviewing or sharing a session. Torque the quick release mount to no more than 2.5 N·m, or 22.13 in-lbs.

Ideal for

• Pig and deer hunters working familiar country where ranges are already known
• Property managers doing overnight fox and rabbit control
• Goat shooters who want reach without paying for a rangefinder module
• Anyone wanting a lighter 35 mm thermal scope for long walks in the scrub