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Thermal scopes / FLIRDiscontinued

FLIR ThermoSight RS64 35mm

640×512 · 35 mm · 4 h · Discontinued

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Ground across the screen at 100 yd

Field width

How many feet of ground fill the screen at 100 yards. Wider makes scanning faster; narrower usually means more detail on the animal.

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95 ft

Wider than 98% of the 208 current thermal scopes we track (#5).

Specs

Sensor
Resolution

Sensor resolution

How many heat-reading pixels the sensor has, such as 384 × 288 or 640 × 512. More pixels show more detail, but the lens matters just as much.

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640 × 512
Pixel pitch

Pixel pitch

The size of each sensor pixel, in microns. Smaller pixels mean more magnification from the same lens. Most current thermals use 12 microns.

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Not published
NETD (maker’s claim)

NETD (thermal sensitivity)

How small a temperature difference the sensor can show. Lower is better, but brands measure it differently, so numbers from two makers are not a fair comparison.

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Refresh rate

Refresh rate

How many times per second the picture updates. 50 or 60 times a second looks smooth; lower rates stutter when you pan or a coyote runs.

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30 Hz
Optics
Lens

Focal length

The lens number in millimeters, like 35 mm or 50 mm. A longer lens puts more pixels on a distant animal but shows a narrower slice of ground.

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35 mm
Base magnification

Base magnification

How much bigger things look before any digital zoom, like 2× or 4×. Higher is not automatically better: it narrows your view.

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1.1×
Max digital zoom

Digital zoom

Electronic enlarging of the picture. It makes the animal look bigger but adds no detail; past about 2× to 4× the image gets blocky.

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9×
Field of view

Field of view

How wide a view you get, in degrees. A wide view makes scanning for animals faster; a narrow one usually means more magnification.

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18° wide
Detection range (maker’s claim)

Detection range

The maker's figure for how far away a warm object shows up as a dot or two. It is far longer than the distance you can tell what the animal is.

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Display
Display

Display resolution

How many pixels the small screen inside the eyepiece has. A sharp screen looks cleaner but cannot add detail the sensor did not capture.

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Active Matrix LCD 640 × 480
Power
BatteryInternal Li-ion
Runtime

Battery life (runtime)

How many hours the device runs on a charge, by the maker's test. Real runtime is shorter in the cold and with Wi-Fi, recording or the rangefinder on.

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4 h
Features
Rangefinder

Laser rangefinder

A built-in laser that measures how far away the animal is. The rated range is for big, reflective targets; expect much less on a coyote.

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No
Storage

Onboard recording (storage)

Built-in memory that records photos and video of what you see. Useful for reviewing shots and sharing hunts; listed in gigabytes.

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Wi-Fi / app

Wi-Fi and app

A wireless link to a phone app for live viewing, downloading videos, changing settings and updating the device's software.

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Riflescope
Eye relief

Eye relief

How far your eye sits behind the eyepiece and still sees the full picture. On a rifle scope, more distance keeps the scope off your face under recoil.

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76.2 mm
Recoil rating

Recoil rating

How much rifle recoil the maker says the scope can take and still work and hold zero. Makers state it in different units, so compare carefully.

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MSR semi-automatic up to .308 caliber
Mount

Mount

How the scope attaches to the rifle: standard rings or a rail clamp, fixed or quick-detach. A good mount does more to hold zero than anything else.

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MIL-STD-1913 Picatinny rail
Ballistic calculator

Ballistic calculator

Software in the scope that moves the aiming point for distance, using your bullet's data and the range to the animal.

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Zero profiles

Zero profiles

Saved sight settings for different rifles or loads. Switch profiles instead of re-zeroing when you move the scope or change ammunition.

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Build
Weight

Weight

How heavy the device is. Check whether the maker weighed it with or without the battery, because brands do it differently.

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Not published
Water rating

IP rating (water rating)

A two-part code for how well the device keeps out dust and water. IP67 means dust-tight and survives a short dunk; an X means not tested.

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IPX7
Operating temp

Operating temperature

The temperature range the maker says the device will work in. Batteries lose much of their runtime well before the low end of that range.

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-4°F to 122°F
Buying
Warranty

Warranty

How long the maker promises to repair or replace a faulty unit. Check whether it needs registration and whether it passes to a second owner.

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2 years standard, 3 years with registration, 10 years on the thermal sensor
US price

US price

The price we found for the unit in the US, with where it came from and when. Prices change often, so treat it as a snapshot.

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Discontinued
MSRP

MSRP

The maker's suggested retail price in the US: the list price, before any sale. Useful for seeing how good a deal really is.

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Not published for USNo list price found on flir.com; Wayback captures of the product page were not checked for a price in this pass

Source: FLIR RS64 product page with both lens variations (Wayback Machine capture of July 26, 2018), FLIR ThermoSight RS64 product page (Legacy Riflescopes, marked Discontinued), FLIR Outdoor and Tactical Systems 2-3-10 limited warranty (PDF).

Added October 11, 2026 · Specs last checked October 11, 2026