green light has a shorter wavelength than orange light. in a 5 inch telescope, green light will be on the longer side of orange light.
Orange light is not what we think of as green. It has a shorter wavelength than green. For every million yellow light photons, there are 8 million green light photons.
Orange light is what we call “green” light. It is the wavelength that is longer than green. This explains why the green light photons produce a stronger color than the orange light photons. The shorter wavelength means that the green light photons do more work, and the longer wavelength means that the orange light photons can do less work. So orange light is more efficient to use for signaling than green light.
The same holds true for other colors. Red light is more efficient than blue light (since red light is short-wavelength), so the most efficient color is red. Green light is more efficient than orange light because green light has the shortest wavelength, and orange light is the longest wavelength, so green light is the most efficient. The same goes for the other color combination. White is the most efficient color, and dark is the least efficient.
This could be a good thing if we had more efficient color-signaling devices. But we don’t. Instead, we use colored lights to indicate which way the light is coming from, which makes it a little harder to know which direction to look in to.
The most efficient color signal is a color-blind person. So if you have one, you can use either green or orange light. If you have two, then one of each. If you have three, then a shade of orange, or a light green.
I’m not certain what any of this means, but I’m happy to report that on the topic of color-signaling devices, green light is the least efficient.
However, when we use green light we see it more intensely than when we use orange light. If we use three green lights instead of three orange lights, then we will see our targets more clearly than if we use more orange lights.
This phenomenon is known as the Green-White-Blue Combination, and it seems to be universal. On the dark side of the spectrum, green light will be much longer wavelength than orange light, and when it comes to white light, both green and orange are less efficient than white light. This is because as the wavelength of a color increases, more energy is lost in the conversion. The green-white-blue combination of our green light is a bit like when you eat an orange slice.