Blinking Light pattern for maximum attention distance at night

[jpanhalt]

Colour.  Which color is best recognize by huamn eye at low intensity level (far away long working range)?

Haven't the first three already been answered.  Flashing with a regular pattern, but probably not simply on/off.

As for color at night?  Have you heard about our rods and cones?  Look up night vision. 

[coppercone2]

i heard conflicting information on colors. best to try it yourself

[5U4GB]

Note that you wont find the huge high power Xenons which used to be used for spy plane photography.  Those were designed to light up a small city from a few miles above during the night before the days of digital spy satellite technology.

Wouldn't flying a US military aircraft over a Soviet city and then lighting it up with a bright flash have risked, you know, misinterpretation by the other side?

[5U4GB]

No, led does not flash bright enough to replace a camera xenon flash.  What has happened is that your phone's camera can now operate with 1/100th the light output without delivering a picture full of grain/noise.

Outside of specifically phone-camera use they are bright enough, to the extent that they're used in lighthouses and are visible for tens of km (you can run an LED lighthouse off solar-charged batteries, which is great for remote and automated lighthouses).

[LaserSteve]

Day peak eye sensitivity is around 570 nm yellow. Night peak is around nm green.

Flashing is a must against urban background lighting.  Daylight Warning strobes for radiotowers  are 30-60 short [ xenon strobe ] flashes per minute, switching to short bursts of flashes at night at reduced power and reduced rate, often with a change of color to red. The night adapted brain is confused by a single flash but very much adapted to locating bursts of short flashes.

Aeronautical warning lights have always had a secondary use for navigation back to the 1930s, so they have far higher intensities then they actually need.


Alternating green and yellow or green and white single flashes makes for a strong means to locate a position, which is why that particular sequence is legally reserved for locating airports in the US.

200 to 1000 microsecond flashes l Xenon) [actually out to 100s of milliseconds] win, period.  Running them in burst-pause-burst makes them distinctive

IALAs quick flashing and occulting patterns come in second.

Alternating the location of flashes aka wig-wag aircraft lighting comes in third.

Alternating color in short bursts comes in fourth.

The US FAA has this well spelled out for Anticollision, Tower,  and Airport Beacon lighting in various regulations.

Recently in the US,  alternating yellow green, of a pattern distinctive from the Aviation Beacon pattern has been adapted for construction vehicles on highways. in my State,  Ohio, it was so effective on winter snowplows that a petition circulated to the governor's office to tame it by reducing intensity. It uses alternating colors and motion, and it is Highly effective.


https://youtu.be/X5G2Ya0ZaJ0?si=eN9nHL5FAubGEswb


https://youtu.be/ZAGZVblbS3U?si=S0ro6vgBL_ynvYyI

Ohio State trucks now use alternating yellow and white  in the upper left and lower right and alternating green yellow in two other locations on the rear.  Colors "flip" about twice per second. Using four spaced  beacons with a quadrature phased [90 degree] color wig-wag sequence is amazingly effective.

State Law had to be amended to have green lighting on a vehicle, and requires it to be distinctive from traffic lights at intersections.

Do the pilots a favor and make your sequence different from Morse Code H, white yellow green, white green, white yellow,  white white green, beacons.

Steve