Kestrel Meter Backlights (Understanding NV)
Kestrel Meters come with a couple of different backlight options:
Aviation Green Electroluminescent Backlight & Visible Red Electroluminescent Backlight (NV)
All offer automatic or manual activation. The Red display (NV) is not available in all models and costs a little more.
Military personnel and pilots flying in darkness are often concerned with preserving their night vision. Due to overwhelming demand from our military customers, the Kestrel NV line was added in 2005.
The 'NV' is not about night goggles... It's about avoiding night blindness from looking at the standard green backlight, and then off into the horizon. It has a night-vision preserving backlight which helps users to sustain natural night vision. The NV's backlight incorporates an optical filter to reduce overall brightness and minimize blue and green spectrum light to preserve night vision. Additionally, NV backlights are also much dimmer than a standard backlight, making it more difficult to detect with the naked eye in night operations. This backlight appears soft greyish pink, not red, and is still in the visible spectrum, so is not compatible with night-vision equipment.
It takes 30 to 45 minutes for the average eye to adapt to darkness and maximize night vision. Even a short burst of white, yellow, green or blue light “bleaches out” the rod cell photoreceptors in the eye and causes night blindness until the entire adaptation process can take place again. Light in the red spectrum does not cause this “bleaching out”, preventing night blindness and night vision fatigue.
|My iphone photo really does not give it justice, this is more green in person, much like the color you would see of an "electroluminescent" back lit watch. It definitely gives off some light.||My iphone photo really does not give it justice, this is more red in person, very easy to read, but gives off just enough back light to read the display, almost no light leakage.|
|Why I'd want Green: Cheaper, brighter, gives off a little light, trouble reading small LCD displays||Why I'd want Red: Harder to spot by others, prevents being susceptible to night blindness when using at night. Easy to read.|