What Is The Difference Between Night Vision and Thermal Scopes?
Some animals are naturally born with the ability to see in the dark. Unfortunately, humans are not one of them. We were left to stumble around until someone finally figured out a way to see in the night around the year 1800.
As time went on, the methods were refined. As of today, there two main ways used: thermal or night vision. This article explains how each scope works, the pros and cons of each type, and finally, a guide to help choose which one is the right fit for you.
Thermal Scopes
To understand Infrared Scopes, you first need to understand the electromagnetic spectrum. This spectrum includes everything from radio waves to visible light and beyond. The human eye can only see a small fraction of these wavelengths. This is known as the visible light spectrum, and it makes up everything you can see right now.
Just beyond the range of human vision lies the infrared spectrum. For this article, heat and infrared will be equivalent. The infrared spectrum was first discovered in 1800, and the first infrared sight was invented in 1901, and it could see a cow in complete darkness at 400meters or about 450yards.
Thermal scopes take heat energy and translate it into colors that humans can see. A lens in the content collects the infrared light in the “view” of the content. This infrared light is then scanned by sensors that send a signal to a microprocessor.
The microprocessor translates different amounts of heat into different colors the human eye can see. A thermal scope is a camera that takes pictures of infrared light and then translates it into visible light. This whole process takes only a few fractions of a second.
A thermal scope completes this process about 30 times a second, giving the user a live look at what is in front of him. As thermal optics developed over time, they split into two main categories; cooled and uncooled.
Thermal scopes are un-cooled, meaning they operate at room temperature. These scopes allow users to see a raw image within a temperature range of -4f to 4,000f with a sensitivity of about .5f, more than enough for the average person.
A cooled thermal imager is usually cooled with a system of liquid nitrogen. This makes them bulky and fragile and not very practical to put on top of a hunting rifle. Cooled thermal imagers are often used on military observation planes or even satellites.
A thermal imager cooled by liquid nitrogen is much more sensitive to heat than an uncooled one. A cooled thermal imager is sensitive to changes in temperature up to .02f. This allows the user to see an unbelievably clear image from exceptionally far away. However, with the way technology progresses, it may be possible to one day produce a handheld cooled thermal optic.
Night Vision Scopes
Unlike thermal scopes, which produce images from heat, night vision scopes enhance the already existing light making it visible to the humane eye. Dim light enters the lens of content that strikes a photocathode.
The photocathode converts the light to electrons. The electrons then pass through an amplifier that adds electrons, which strengthens the signal. These electrons collide with a photo screen and create tiny flashes of light. These little flashes of light are what a user sees when looking through a night vision scope.
A night vision scope works like a speaker. It takes an electrical signal and then amplifies the movement to make it recognizable to humans. Unfortunately, this method doesn’t produce colors but rather intensifies the difference between the light levels.
The light-enhancing night vision is usually imagined and portrayed in Hollywood when people think of night vision. Different shades of green with brighter green representing more intense light and darker green or black were no light found by the sensor.