Pat Martin, a marketing genius, was on point when he created the tag line, “We’ve come a long way, baby!” for Virginia Slims in 1968. Of course, a cigarette is simply a cigarette, so his tagline did little more than blow smoke. It would have been better served representing a present-day technology category where product development and applications have been significant and many. Even better for consumers, there has never been a better time to buy than right now. Of course, selling thermal optics successfully means arming yourselves as retailers on the whats, whys and hows of such technology and using the acquired knowledge to educate your customers.
Thermal is not night vision. The two systems employ distinctly different technologies and were spawned from completely different histories — the only similarity being optic systems (most often riflescopes and handheld) capable of productive nighttime imaging. Even so, thermal imagers are true 24-hour optics. They work day or night, and given contrasting temperatures, the field of view should be crisp and richly contrasted around the clock.
Thermal Imaging Simplified
Thermal imaging’s history began in 1800 while Sir William Herschel was busily assessing the sun’s varying degrees of brightness effects on tinted glass. Using a prism, heat transfers from the tinted glass revealed infrared radiation. With Sir William’s technology as a foundation, his son, Sir John Herschel, developed the first thermal image in 1840 by subjecting oil to varying temperatures; he called his invention a thermograph. Development continued through the 19th Century, adding an IR (heat) measuring bolometer in 1880, an infrared camera in the 1920s and, 20 years later, Texas Instruments’ thermographic camera — all of which led to microbolometer sensor development in the ’90s, foundational to today’s thermal optics.
Current thermal technology allows infrared radiation (heat) to be funneled through a germanium-glass objective lens, where it is processed by a phased array into a thermal map that is converted into an electric signal and, finally, processed into the field of view represented on a device’s display. The process occurs without casting infrared illumination and, contrary to night vision, works as well in daylight as it does in zero light.
Night Vision Basics
Newer technology than thermal, night vision kicked off during WWII with Germany’s use of NIR (near infrared) optic systems, featuring a large NIR illuminator. Generational night vision as used today originated in the early ’50s and employed more advanced image intensifying tubes. The result was generational night vision beginning with Gen 0 active-infrared (IR always on), moving into Generation 1 through 3 with passive IR illumination (ability to turn IR on and off). Gen 3 is the latest iteration, with a nighttime detection range pushing 400 yards and beyond.
Unfortunately, generational night vision components are quickly damaged if used in daylight. Digital night vision, with the use of CCD or CMOS sensors, is not damaged via use in daylight hours; however, all night vision requires light in the environment or IR illumination to process light particles into exponentially more light particles. Generational night vision passes light particles (photons) into an image intensifier tube to be processed through the photocathode (photons converted to electrons), multichannel plate (electrons converted to exponentially more electrons) and the phosphor screen where they are converted back to photons to create the image. Digital night vision works similarly; however, instead of converting photons to electrons and back to photons, light particles are converted to an electric signal via a CCD or CMOS sensor and sent to be represented on a display.
A straightforward way to remember fundamental infrared differences in thermal and night vision technologies is simply that thermal detects and processes infrared radiation onto a display while night vision uses available light, including cast IR illumination from the device, to process the light into an image on the display. As a result, the most extreme temperature (heat) glows on a thermal display where a field of view on night vision (generational and digital) is quite muted, and why thermal detection ranges also are much longer. This is why, when users can afford the technology, they generally opt for thermal optics over night vision.
Affordable Performance: Sightmark’s Wraith Mini Thermal Riflescope
The good news here is that while thermal imagers cost anywhere from $15,000 to $30,000 just 15 years ago, today, premium thermal optics average $6,000 to $8,000. Fortunately, performance thermal imagers also can be found at much more affordable price points, some costing even less than premium traditional day optics. As a notable example, the Sightmark Wraith 2-16x35 Thermal Riflescope costs about $1,700, about half the price of one of my precision long-range daytime scopes.
The Wraith really shines in value here as a true feature-rich thermal optic, boasting a Lynred 384x288 microbolometer sensor, 17-micron pixel pitch and sub-40mK NETD sensitivity. The Wraith also features a 1,400-yard detection range, five-color display palette, 10 reticles styles in nine colors, 1024x768 OLED display, 35mm objective lens and onboard video, all packed into a Picatinny-rail mountable compact design, roughly the size of an ACOG scope. The Wraith Mini Thermal runs up to 4.5 hours on two CR123A batteries and is compatible with Sightmark’s Mini QD Battery Pack, a Picatinny-rail mountable power source delivering over eight hours of operation. Learn more at www.Sightmark.com.
