Red Mode / Night Mode on iPad

[noelex 77]

There is a different opsin in rods and cones (in fact there are also three different types of cones). This is, in part, why the rods and cones have a different spectral sensitivity.

A lot of modern military planes cannot be made dark enough to develop full dark adaption. The instrument information is extremely important and takes priority. This is the likely reason why red illumination was not used. If the aircraft's crew is operating at a high mesopic level, red light is not helpful.

Dull red illumination is very difficult to use. It diminishes the information from the instruments There is no colour coding possible for example. It also makes focusing more difficult. This loss of instrument performance is why it was not used on milatary planes such as you describe.

Yachts are unusual modern vehicles where occasionally it helpful to be steering them in full scotopic mode (in the sort situation I described in my previous post). Only very dull red illumination can preserve this level of dark adaptaion. This is because of the way the physiology of the eye works and not even the USA military can change that .

[guyrj33]

" I could just figure out how to keep my Aqua Signal LED's I have in the cockpit from flickering "
A series resistor might solve the problem by keeping the system at a power consumption level where the controller has to fire more often.

[a64pilot]

AH-64A had regular instrumentation for the most part, so what we did was turn all the cockpit illumination off and put one blue green LED mounted on our microphone with a micro switch, called them "lip lights" that way cockpit was completely dark until you needed to see something inside, then look at what you needed to see and poke your lip out to turn the light on. Worked really, really well.
Of course they are fancy now and manufactured where ours were home made, you can put on on your finger too, just point at what you want to see.
http://www.helicoptersonly.com/contents/en-us/d178.html

AH-64D or Longbow is all glass cockpit, and you can't turn an MPD off and shine a light on it, a step backwards to some extent. Same problem with modern boats, you can't get an MPD dark enough to not ruin some night vision.
Then on a good moon night there is enough illumination to see photopically anyway, as a young guy I could discern colors when others could not, I had phenomenal vision.

[noelex 77]

The planes are very different but our eyes are the same.

A little history may help.

The superiority of red illumination was established well before WW2. Thus, all night illumination was red. This was followed for far too long as instrument displays became far more sophisticated and pilots needed to process complex information quickly. Red illumination is very poor for this. Having no colour information is particularly restrictive. Its much better to colour code information, so say the good guys stand out from the bad guys.

So it was gradually realised that it worth sacrificing some night vision so complex instrument information could be presented and be processed rapidly by pilots etc. The final reason was that red illumination does not work well with night vision equipment. For all these reasons instrument illumination gradually changed to (most commonly) white.

A yacht's requirements are sometimes similar. AIS, radar and chart plotters provide great information. It often does not need to be processed rapidly, things happen slower on a boat than on a plane, but is often worth sacrificing some night vision so the instrument information can be assimilated quickly and giving up some night vision is often a worthwhile tradeoff. Dull white illumination is best here. However, there are other times on a yacht where visual information is king, and the option of preserving this and still receiving some instrument information is the best option. This is not dissimilar to how a simpler WW2 aircraft was typically operated at night. Red light is much better for this.

On a yacht there is also the requirement to do quite simple visual tasks (such as making a cup of coffee or getting dressed). This can be done with minimal visual acuity and for this a dull red light is ideal.

[a64pilot]

This is the dimmer I'm using, it had very little improvement over the cheapo one I was using, I thought the high frequency would stop the flickering?
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[BURMABOB]

Thank You Mr. Dave Walters...I really appreciate and I printed out your instructions...Tell your Wife..You are AWESOME...regardless of what the In-Laws think...

Burma

[Huskybeer]

I as ophthalmic surgeon fully agree.
There are interesting trials by changing the nutritional balance to influence the dark adaptation capabilities

[noelex 77]

Originally Posted by a64pilot

Then on a good moon night there is enough illumination to see photopically anyway, as a young guy I could discern colors when others could not, I had phenomenal vision.

Seeing colour is a good guide to the level of illumination. If you can see colour your eyes are working at the photopic or at least a reasonable mesopic level.

Scotopic vision (which is vision preseved by red illumination) is at much duller level. If you are seeing colour in the sea, sky or ships (ignoring their lights) there is no point using red illumination. On the other hand if you go down to make a cup a coffee and can see some colour you are also opperating at photopic or resonable mesopic level and if it dark enough outside it will be 10 mins or so before you regain your full scotopic dark adaptation. There is nothing that speed this up and a few things that can slow it down. If exposed to even moderatly bright photopic illumination levels it can 30mins or more before you have maximium dark adaptation.

This is why it is important to guard your night vision. Sometimes it worth giving up some night vision ability for example to examine a chart with colour information, but give some thought if the loss is worthwhile.

It is very difficult to make a cup a coffee with white light and still preserve your full scotopic vision. It has to be so dull that you will not be able to see if there is coffee on the spoon. With red light it still has to be dull, but as the rods in your retina cannot see red light they will not become bleached.

[ArmyDaveNY]

Originally Posted by a64pilot

Same problem with modern boats, you can't get an MPD dark enough to not ruin some night vision.
Then on a good moon night there is enough illumination to see photopically anyway, as a young guy I could discern colors when others could not, I had phenomenal vision.

Very true! I often turn off the electrical navigation devices, with the occasional exception of radar, if I have it. This is true even when along a coast on a clear night. Very often I find the stars alone provide more than enough light to see and often even read. This is even more true on a well lit night.

Someone else pointed out how important light discipline is, and they are correct. One technique that sometimes works is to close one eye when you need to look at some light. This, in theory, saves the night vision in the closed eye. When done properly, it does help.

[a64pilot]

Deleted, already posted

[tstano]

Originally Posted by DaveWaltersAus

Maybe I'm a "gumbie" and this is old news to old salts but I've been trying to do this for two years.

My wife is laughing at me because I think it's so cool - I had to tell someone who might appreciate it so I finally signed up on this forum! I hope it helps!!

You're the second coolest guy in this post. Careful using the red light, it turns bananas black, then you have to throw them away.

All U Get

[Brendan]

Dave,
Thanks very much, this is great - I've tried it and it works a charm. Will use it in the Fastnet in a few weeks!
Ciao, Brendan

[tomdidit]

Originally Posted by BURMABOB

Thank You Mr. Dave Walters...I really appreciate and I printed out your instructions...Tell your Wife..You are AWESOME...regardless of what the In-Laws think...

Burma

I agree heartily. Your I-Pad lesson makes you the man. The quick thread drift was a little more scientific than I would have preferred and must come from those that are not using I-Pads. Thanks, and let your wife know there are a few of us that really appreciate it.

[StuM]

Originally Posted by noelex 77

On a yacht there is also the requirement to do quite simple visual tasks (such as making a cup of coffee or getting dressed). This can be done with minimal visual acuity and for this a dull red light is ideal.

Or an eye patch over one eye.

Back in the day, I always closed one eye when I needed to use a torch to look at a map or whatever at night, I still do it at times when I go below at night for some reason.

[ArmyDaveNY]

Originally Posted by StuM

Or an eye patch over one eye.

Back in the day, I always closed one eye when I needed to use a torch to look at a map or whatever at night, I still do it at times when I go below at night for some reason.

Plus the eye patch gives you cred with the actual pirates! Does it work with the digital pirates?