640 Thermal Scopes
Short version: 640 refers to the thermal sensor, usually 640x512 and sometimes 640x480. It carries about three times the pixels of a 384 core, which you notice the moment you zoom in on something warm at the far edge of a field and need to know whether it is a coyote or a calf. Every scope and clip-on below runs a 640 core, from AGM, ATN, Pulsar, Nocpix, SIG Sauer, Pard, RIX and Athlon.
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1280 thermal scopes · 384 thermal scopes · 256 thermal scopes · all thermal scopes · thermal monoculars · RIX thermal scopes
What a 640 core gets you
Resolution is the pixel count of the thermal sensor, and it sets the ceiling on detail. A 640x512 core has 327,680 pixels. A 384x288 core has 110,592. The gap shows up in two places. Digital zoom holds together on a 640 at magnifications that turn a 384 picture into blocks, and more pixels on the animal means fewer guesses before you decide to shoot.
| Core | Pixels | Compared with 384 | Where it fits |
|---|---|---|---|
| 256x192 | 49,152 | Less than half | Close work and budget builds |
| 384x288 | 110,592 | Baseline | Most coyote and hog setups |
| 640x512 | 327,680 | About 3x | Identification at distance, heavy zoom |
| 1280x1024 | 1,310,720 | About 12x | Maximum detail, big open country |
640x512 or 640x480
Both get sold as 640. The 640x512 sensor has 32 more rows of pixels, roughly 7% more image, and gives a slightly taller view. In the field the difference is small. Compare the lens and the price before you let 32 rows make the decision.
Read the lens number too
The millimeter figure is the objective lens. A bigger lens on the same core gives more base magnification and a narrower field of view, so a 50mm 640 reaches farther and a 35mm 640 sees wider. Many model names spell it out: an AGM Rattler 35-640 is a 35mm lens on a 640 core. Open fields and long calling setups favor 50mm and up. Hogs in timber and along fencerows are easier to follow with a 35mm.
Sensor resolution vs display resolution
Spec sheets list two resolutions. The sensor captures the heat. The display, often 1024x768 or higher, is the screen behind the eyepiece. A sharp screen makes the image pleasant to look at, and it still cannot add detail the sensor never recorded. When you compare scopes, compare the sensor line.
Dedicated scope or clip-on
A dedicated thermal scope replaces your day optic and carries its own reticle, with a built-in rangefinder and recording on many models. A clip-on mounts in front of the day scope you already shoot, so you keep your own reticle and pull the thermal off when the sun comes up.
Check the law before the first hunt
Whether you can hunt with thermal depends on your state, the species and the season. Your state wildlife agency's current regulations are the final word, so read them before you take a thermal scope to the field.
640 thermal scope FAQs
Is a 640 thermal scope worth it over a 384?
If most of your shots are close and your fields are small, a good 384 thermal scope does the job and saves real money. If you hunt open ground, lean on digital zoom or need to identify at distance, 640 is the upgrade you will notice every night.
What is the difference between 640x512 and 640x480?
32 rows of pixels. The 640x512 core gives a slightly taller image with about 7% more pixels. Both are full 640-class sensors.
Can you use a 640 thermal scope during the day?
Yes. Thermal reads heat, so it works in daylight. Contrast can drop around sunrise and sunset, when the ground and the animal sit at similar temperatures.
Should I skip straight to 1280?
Only if the budget is there and you regularly identify at long range. A 1280 core carries four times the pixels of a 640 and is priced accordingly. Compare them on our 1280 thermal scopes page.
Is it legal to hunt with a thermal scope?
It depends on your state, the species and the season. Check your state wildlife agency's regulations before you hunt.