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

[Wireless1]

Originally Posted by 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

THAT SETTLES IT BILL!!! Since my only helm is amidships I'm going to install both RED and GREEN LED's in my compass with a mercury switch. On port tack I'll have a red compass light and on starboard a green one. That should please EVERYONE!

[Bash]

Originally Posted by Wireless1

On port tack I'll have a red compass light and on starboard a green one. That should please EVERYONE!

Everyone? Maybe not those of us who are colorblind.

(Not that I need a light to know whether I'm on port tack. Bottom line: in a crossing situation, I'm always on port tack.)

[Wireless1]

Originally Posted by Badsanta

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

Ha! Yeah, I know at first UV sounds silly, but I'm curious why nobody uses it for a compass light. It would seem to me to be ideal. If the UV LED was dimmed down I would think it would look like there was NO light at all but your compass lines and numbers would be glowing very bright white. Seriously; anything wrong with that?

[noelex 77]

Originally Posted by IslandHopper

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.....

Using a green light will be much easier, but you need to realise that it will totally bleach out your rod system. Sometimes this sacrificing of your scotopic dark adaptation is worthwhile particularly in situations where a chart plotter or radar are more imortant than a visual lookout.
In other situations it is helpful to maximise your dark adaption often with minimal instrumentation. To use this mode you need to have basic instruments such as the compass, log and depth with dull red illumination.
Often the ideal situation is between these two extremes. Too many yachts always use a setup that it seriously compromises their dark adaption, often because they don't think about the alternatives, but sometimes because it is impossible to set the boat up any other way.

[IslandHopper]

Originally Posted by noelex 77

Using a green light will be much easier, but you need to realise that it will totally bleach out your rod system. Sometimes this sacrificing of your scotopic dark adaptation is worthwhile particularly in situations where a chart plotter or radar are more imortant than a visual lookout.
In other situations it is helpful to maximise your dark adaption often with minimal instrumentation. To use this mode you need to have basic instruments such as the compass, log and depth with dull red illumination.
Often the ideal situation is between these two extremes. Too many yachts always use a setup that it seriously compromises their dark adaption, often because they don't think about the alternatives, but sometimes because it is impossible to set the boat up any other way.

Just having the compass, log and depth would be viewed the height of irresponsibillity on my bridge, and i don't spend all my time staring into the radar but devote time to all the instuments at my disposal including keeping a visual lookout......

To try and say that all will suffer the same results is just incorrect, i know after a working lifetime in my profession what works for me and what doesn't. From looking into a red screen to looking out of the bridge windows my eyes take longer to adjust than if i was looking into the green. I’m not alone in this, and this is one of the reasons why radar and other instruments are manufactured with the choice.....

Also I did once ask an eye specialist for the reason why (we are required as others are to have regular eyesight checks) and he did give me a very thorough and scientific answer, for which most of it flew over my head, but the important part for me was that not everyone reacts the same way to colours and light and i was not abnormal.... although swmbo disbutes the abnormal bit...

[noelex 77]

[

Originally Posted by IslandHopper

Just having the compass, log and depth would be viewed the height of irresponsibillity on my bridge, and i don't spend all my time staring into the radar but devote time to all the instuments at my disposal including keeping a visual lookout......

To try and say that all will suffer the same results is just incorrect, i know after a working lifetime in my profession what works for me and what doesn't. From looking into a red screen to looking out of the bridge windows my eyes take longer to adjust than if i was looking into the green. I’m not alone in this, and this is one of the reasons why radar and other instruments are manufactured with the choice.....

Also I did once ask an eye specialist for the reason why (we are required as others are to have regular eyesight checks) and he did give me a very thorough and scientific answer, for which most of it flew over my head, but the important part for me was that not everyone reacts the same way to colours and light and i was not abnormal.... although swmbo disbutes the abnormal bit...

The best solution will vary with conditions and from vessel to vessel, but it's important to relise, under the conditions you have described, everyone will bleach out their rods and loose about half their dark adaption This is due to to the eyes physiology and is not subject to individual variation.(There are some eye conditions that make using red light more difficult and you may be suffering from one of these problems, but the loss of night vision is universal)
Knowing this is half the battle and should help you make better decisions. In a MOB situation for example it may be prudent to cover the radar or appoint another crew member to position themselves away from the light sources so they can gradually attain full night vision.

[Wireless1]

Originally Posted by Wireless1

Ha! Yeah, I know at first UV sounds silly, but I'm curious why nobody uses a UV "black-light" for a compass light. It would seem to me to be ideal. If the UV LED was dimmed down I would think it would look like there was NO light at all but your compass lines and numbers would be glowing very bright white. Seriously; anything wrong with that?

I say again... Any reason for NOT using a UV compass light?

[dacust]

Originally Posted by Wireless1

I say again... Any reason for NOT using a UV compass light?

I think it would be fine if your particular compass has numbers and registration lines that respond to UV and nothing distracting that does as well.

-dan

[dandrews]

Originally Posted by Wireless1

I say again... Any reason for NOT using a UV compass light?

Since my compass is in my workshop right now. I may play around with UV and see how it works out.

[thinwater]

a. with white or green light you can use much less light than with red. The falicy, in my understanding, is that we are comparing equal levels. The truth is that we see red very poorly and thus need more of it for it to be useful. Rather, whatever the studies say, this is the truth many of us have observed.

b. When I really need night vision I through a towel over everything. If I need it, I can move it, but often zero instrument light is the best answer.

[noelex 77]

Originally Posted by thinwater

a. with white or green light you can use much less light than with red. The falicy, in my understanding, is that we are comparing equal levels. The truth is that we see red very poorly and thus need more of it for it to be useful. Rather, whatever the studies say, this is the truth many of us have observed.

.

The level is not important only how bright the light appears to an observer. A very high level UV or IR source will have no impact on dark adaptation, for example.
A high level far blue or red light will appear dull to an observer, because the eye the not sensitive to these wavelengths and will have less impact on dark adaption.

The trick with red is that we have two different types of receptors and the rods are not sensitive to red. So we can use red to see with our cones without bleaching out our rods.

Originally Posted by thinwater

b. When I really need night vision I through a towel over everything. If I need it, I can move it, but often zero instrument light is the best answer.

That's a good solution. Rember though it will take about 15 mins before you get full dark adaption if you have been using a chart plotter or instruments with white light.

[Wireless1]

Well, I see one disadvantage to UV LED's for compass lights. They are between $49 and $99 EACH! (Depending on what lens you select). WOW! I had no idea they would be that expensive. If anyone has a cheap source let us know... The first of the week I'm going to call the tech rep at Sensor Electronic Tech, Inc. and see what they say about use as experimental compass lighting and also what lens type they would recommend. They also come in a wide range of frequencies (240nm to 360nm) and I have no idea how that would translate to making the compass markings (white) in my Richie Globe Master stand out. Also, I've discerned from their literature that one should NOT look directly into the LED lens. This should not be a problem with the compass as it has a hood over the light. Still, I wonder about reflections...

[noelex 77]

UV may work, by illuminating only the markings it will help reduce the overall amount of light produced, but the makings will glow white, which is not ideal.

The biggest problem is that many of the compass housings are polycarbonate with does not transmit UV so the LED will probably need to be inside the dome which is going to be difficult to do.

If you want to experiment I would think a LED with a long UV wavelength, but no output above 400nm which is limit for vision, will work best.

[deckofficer]

All I know is the red illumination finally forced my hand to get reading glasses at the age of 44. I was reading a chart with a hand held magnifying glass and the old man told me I should get some reading glasses. Next port I did, and have used them ever since. Found out that for computer work I need less magnifying power than for reading print or charts with the red illumination.

[Wireless1]

Originally Posted by noelex 77

UV may work, by illuminating only the markings it will help reduce the overall amount of light produced, but the makings will glow white, which is not ideal.

The biggest problem is that many of the compass housings are polycarbonate with does not transmit UV so the LED will probably need to be inside the dome which is going to be difficult to do.

If you want to experiment I would think a LED with a long UV wavelength, but no output above 400nm which is limit for vision, will work best.

Well...if the dome won't let UV penetrate then the deal is off. I can't see trying to engineer a UV LED inside the globe in the fluid! Ha! Maybe the best test is just to get a UV LED flashlight first and see how much UV can be forced through the polycarbonate. It may be that the polycarbonate has a high resistance to UV....but not a total resistance. Do you have any numbers on the percentage of filtration?

The company I mentioned doesn't have anything above 360nm so their UV LED's won't be visible light to the human eye. I was thinking of experimenting with a series resistor to "dim" the LED down so the white markings on the compass card wouldn't JUMP out so much. This shouldn't be a problem with a resistor substitution box. However, all that being said, I'm not sure I'm ready to dump 50 to 100 bucks on ONE LED that is extremely temperamental on how you handle it. Their specs say you can solder to the leads but no more than 5 seconds heat application, and no nearer that 3mm to the TO-18 case and you can NOT surface mount to a PC board. Even though I was a bench tech in the electronic repair business as a young man, this is a test of one's soldering skills. Their list of No No's on handling seem a bit intimidating. Still, how cool would it be to see NOTHING but the lettering/lubber-lines and divisions on your compass card with no perceivable lighting ruining your night vision. It may be worth a shot.