Endurance.Net Ridecamp Archives

"Paul Bendzunas" wrote:

"While at the beach last summer we came across a turtle laying eggs and called the turtle patrol. They told us we could watch but we had to use red light because turtles are color blind and can't see red light, therefor the light would not disturb it.I have a headlamp that has red light and I use it around camp sometimes because it appears not to effect the horses.Maybe it's because such a soft light and it doesn't create harsh shadows.Also when you turn it off you're night vision comes back fast."

 

This pretty much explains why (from http://en.wikipedia.org/wiki/Night-vision):

"Biological night vision works on similar principles. Rhodopsin in the rods of the eye break as light hits it. The peak rhodopsin build up time for optimal night vision in humans is 30 minutes. Rhodopsin in the human rods isn't sensitive to the longer red wavelengths of light, so many people use red light to preserve night vision as it will not deplete the eye's rhodopsin stores in the rods and instead is viewed by the cones."

This explains why other riders get cranky when someone uses a headlamp - it messes up their and their horses' night vision for a long, long time......

Dana

 

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