What's it Going to Be ? Red or Green LED Compass Light ?

[Wireless1]

I guess I've been away from sailing too long. What's up with green compass lights? I've only used red. My older Richie SP-5 Globe-master needs new lighting, so of course I'm thinking LED. Then I see there are two color options; red or green.
I'd like some opinions on what are the pluses and minuses of green vs. red.
Or maybe I should get a SPDT center off switch and get both to entertain myself! Thanks for any opinions....

[Paul Elliott]

My binnacle compass has a green LED and I like it. I think it is probably easier to read than it would be with a red light. Here it is on a moonlit night (time-exposure, it's not really this bright):


The red lights in the cabin are so we don't bump into stuff. For reading tiny numbers I prefer green or dim white.

[noelex 77]

Red will preserve your night vision much better, but will be less comfortable to use. If you can vary the illumination, dimming it as you dark adapt, when good night vision is important it will be better again.

[Bash]

Green is easier to read.

[James S]

Originally Posted by Paul Elliott

My binnacle compass has a green LED and I like it. I think it is probably easier to read than it would be with a red light. Here it is on a moonlit night (time-exposure, it's not really this bright):


The red lights in the cabin are so we don't bump into stuff. For reading tiny numbers I prefer green or dim white.

Cool picture ...thanks!

[denverd0n]

Red has always been the traditional color for night lighting, because of the belief that it did not affect your night vision. In fact, more recent study has shown that the main thing is to keep the light as dim as possible. In other words, a bright red light will affect your night vision just as much as any other color light of the same brightness. The only real difference is that your night vision will recover marginally more quickly from exposure to bright red lights (the difference, however, is so small as to hardly matter).

As such, the current wisdom is to use whatever color of light is best for whatever it is that your looking at, but to keep the light as dim as possible. So, for instance, if your compass has red markings on it (which will be very difficult to see under red light) you will be better off with a green light. And, of course, vice versa.

[thinwater]

Search and you will find that there have been more resent studies refuting the red-at-night conventional wisdom. Green or blue are probably the better choices, but what is most important is that it is dim.

The aviation industry has studied this to death.

Cockpit Lighting: Part II: The effect of lighting color on night vision

"The American Optical Association said that red lighting on the flight deck requires more focusing power than white light or blue-green light for near objects to be observed clearly. This may cause difficulty, especially for pilots in their 40s and older with presbyopia—the most common age-related change in vision—in which the eyes become less able to focus on nearby objects."

[senormechanico]

I installed a white LED and experimented with a series resistor value until I got the brightness I wanted. It's been years since I installed it, but I believe it was 1k ohms.

[rebel heart]

I know I'm going to piss people off but the whole "red will preserve your night vision" thing is bunk. Night Vision - The Red Myth

[Wireless1]

Thanks everyone. After reading the links and opinions I'm going to give green a try. I had never thought about it before but I can personally attest to the trouble I have focusing on a small red LED bedside clock. That thing is ALWAYS fuzzy looking to me at night.

Here's another idea that popped up. I wonder if anybody has tried a UV (black-light) LED? I the light from it would not be visible at all, but the compass markings, being white, should glow quite nicely. On further inspection and searching I ran across the following statement on Wikipedia which I had never heard before.

>> "One of the innovations for night and all-weather flying used by the US, UK, Japan and Germany during World War II was the use of UV interior lighting to illuminate the instrument panel, giving a safer alternative to the radium-painted instrument faces and pointers, and an intensity that could be varied easily and without visible illumination that would give away an aircraft's position. This went so far as to include the printing of charts that were marked in UV-fluorescent inks, and the provision of UV-visible pencils and slide rules such as the E6B.

So, that ponders the question; Has anyone tried a UV LED compass light before?

[noelex 77]

Originally Posted by rebel heart

I know I'm going to piss people off but the whole "red will preserve your night vision" thing is bunk. Night Vision - The Red Myth

This artical keeps getting quoted, but it has been written by someone with a very poor knowledge of the visual system.

[senormechanico]

Some interesting links:

Eye's Response to Light
Luminosity function - Wikipedia, the free encyclopedia
PHOTOPIC LUMINOUS EFFICIENCY FUNCTION OF THE HUMAN RETINA

[btrayfors]

Red compass lights are for the port helm station.

Green compass lights are for the starboard helm station.

Blue lights are for the joystick buttons (used to walk your boat sideways into the dock).

White lights are totally useless, except for showering and fixing grub.

:-)

Bill

[IslandHopper]

Originally Posted by thinwater

Search and you will find that there have been more resent studies refuting the red-at-night conventional wisdom. Green or blue are probably the better choices, but what is most important is that it is dim.

The aviation industry has studied this to death.

Cockpit Lighting: Part II: The effect of lighting color on night vision

"The American Optical Association said that red lighting on the flight deck requires more focusing power than white light or blue-green light for near objects to be observed clearly. This may cause difficulty, especially for pilots in their 40s and older with presbyopia—the most common age-related change in vision—in which the eyes become less able to focus on nearby objects."

Truthfully i could have told them that 20+ years ago, when i go up to the bridge for my watch i always switch the colour of the radars from red to green....

I also find once i have set the radar to my liking i can read it perfectly from a greater distance than i ever could when it's set to red....

A resounding vote for green from me.....

[Badsanta]

ooooh, black lights, a green glow in the cockpit with black lights on the sail,
way cool. Another project!