Please explain

[T3]

I used to live on a lake just south of Orlando International Airport(just
outside the departure zone) on almost a straight line between Jax NAS and
the Avon Park bombing range, about 20 miles from our house. We were privy to
all kinds of aircraft,form 'Bones' to F-15's, F-14's FA/18's, A-6's, A-10's
and some we couldn't recognize. The A-10's were our favorites, though the
B-1B's were awesome. One evening about 7 years ago (around twilight) as I
was docking my boat, a single F/A18 was dropping to attack altitude at what
appeared to be mil speed and as he came by(approx200ft on the left) I
noticed what appeared to be an iridescent green box just forward and under
of the canopy on the left side. As a 30 year aircraft mechanic for Pan Am it
has always bothered me that I had no valid explanation for it. Was it an
anomaly or was I just hallucinating after catching no fish, if there are any
F/A18 drivers out there who can tell me without betraying any secrets, and
solve this mystery of mine, I'd appreciate it. Thanks in advance

George

[BUFDRVR]

>I
>noticed what appeared to be an iridescent green box just forward and under
>of the canopy on the left side.

Sounds like formation lighting. There should have been a stripe on his
vertical stab as well.


BUFDRVR

"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"

[user]

I think you're right BUFDRVR. Additionally with the continuing push
and installs of NVS, they won't be used very much at all in tactical
situations.

On 11 Nov 2003 13:53:28 GMT, (BUFDRVR) wrote:

>>I
>>noticed what appeared to be an iridescent green box just forward and under
>>of the canopy on the left side.
>
>Sounds like formation lighting. There should have been a stripe on his
>vertical stab as well.
>
>
>BUFDRVR
>
>"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
>everyone on Bear Creek"

[Chad Irby]

In article >,
"T3" > wrote:

> One evening about 7 years ago (around twilight) as I was docking my
> boat, a single F/A18 was dropping to attack altitude at what appeared
> to be mil speed and as he came by(approx200ft on the left) I noticed
> what appeared to be an iridescent green box just forward and under of
> the canopy on the left side. As a 30 year aircraft mechanic for Pan
> Am it has always bothered me that I had no valid explanation for it.

Look at this photo:

<http://www.fas.org/man/dod-101/sys/ac/f-18-bnd980501219.jpg>

See the three rectangles just under the number "731" on the nose?

Those are electroluminescent lights, used for formation flying at night.
They put out a mild greenish-yellow glow.

They're related to the EL backlights seen on watches.

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.

[user]

Great picture Chad,
I'm thinkin that with NVS, the lights are blue? Not sure, but it would
make sense. I know before NVS came out the formation lights were all
green, but this would overdrive and blind NVG's. Wouldn't changing the
lights to blue be part of the NVS mod, or do they just keep em turned
off?

On Tue, 11 Nov 2003 17:53:26 GMT, Chad Irby > wrote:

>In article >,
> "T3" > wrote:
>
>> One evening about 7 years ago (around twilight) as I was docking my
>> boat, a single F/A18 was dropping to attack altitude at what appeared
>> to be mil speed and as he came by(approx200ft on the left) I noticed
>> what appeared to be an iridescent green box just forward and under of
>> the canopy on the left side. As a 30 year aircraft mechanic for Pan
>> Am it has always bothered me that I had no valid explanation for it.
>
>Look at this photo:
>
><http://www.fas.org/man/dod-101/sys/ac/f-18-bnd980501219.jpg>
>
>See the three rectangles just under the number "731" on the nose?
>
>Those are electroluminescent lights, used for formation flying at night.
>They put out a mild greenish-yellow glow.
>
>They're related to the EL backlights seen on watches.

[BUFDRVR]

>I'm thinkin that with NVS, the lights are blue? Not sure, but it would
>make sense. I know before NVS came out the formation lights were all
>green, but this would overdrive and blind NVG's.

Actually Green lighting is better than Blue lighting for NVGs. Anything with
shades of Red light (Green + Red = Blue) will wash out the NVGs.


BUFDRVR

"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"

[Chad Irby]

In article >,
user > wrote:

> I'm thinkin that with NVS, the lights are blue? Not sure, but it would
> make sense. I know before NVS came out the formation lights were all
> green, but this would overdrive and blind NVG's. Wouldn't changing the
> lights to blue be part of the NVS mod, or do they just keep em turned
> off?

I haven't seen them on recent planes, but it's not a hard modification
to make - just a different formula in the EL panels.

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.

[James Hart]

BUFDRVR wrote:
>> I'm thinkin that with NVS, the lights are blue? Not sure, but it
>> would make sense. I know before NVS came out the formation lights
>> were all green, but this would overdrive and blind NVG's.
>
> Actually Green lighting is better than Blue lighting for NVGs.
> Anything with shades of Red light (Green + Red = Blue) will wash out
> the NVGs.

Green + Red = Blue???
Mind boggles.

--
James...
http://www.jameshart.co.uk/

[T3]

"Chad Irby" > wrote in message
...
> In article >,
> "T3" > wrote:
>
> > One evening about 7 years ago (around twilight) as I was docking my
> > boat, a single F/A18 was dropping to attack altitude at what appeared
> > to be mil speed and as he came by(approx200ft on the left) I noticed
> > what appeared to be an iridescent green box just forward and under of
> > the canopy on the left side. As a 30 year aircraft mechanic for Pan
> > Am it has always bothered me that I had no valid explanation for it.
>
> Look at this photo:
>
> <http://www.fas.org/man/dod-101/sys/ac/f-18-bnd980501219.jpg>
>
> See the three rectangles just under the number "731" on the nose?
>
> Those are electroluminescent lights, used for formation flying at night.
> They put out a mild greenish-yellow glow.
>
> They're related to the EL backlights seen on watches.
>
> --
> cirby at cfl.rr.com
>
> Remember: Objects in rearview mirror may be hallucinations.
> Slam on brakes accordingly.



That's it! One mystery solved, Thanks.
T3

[BUFDRVR]

>Green + Red = Blue???
>Mind boggles.

hmm, doesn't it? I have an idiglo Timex that has a blue light, I was told by
the NVG instructor in my squadron that it would work well enough, but would
have been better if it were green. He then gave me that exact line I gave you
above, anything with shades of red in it will tend to wash out NVGs. Anyone out
there have a clue better than mine? Any color spectrum experts?


BUFDRVR

"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"

[Kevin Brooks]

(BUFDRVR) wrote in message >...
> >Green + Red = Blue???
> >Mind boggles.
>
> hmm, doesn't it? I have an idiglo Timex that has a blue light, I was told by
> the NVG instructor in my squadron that it would work well enough, but would
> have been better if it were green. He then gave me that exact line I gave you
> above, anything with shades of red in it will tend to wash out NVGs. Anyone out
> there have a clue better than mine? Any color spectrum experts?

I believe what he was referring to is the fact that red, green, and
blue are *the* primary colors. As blue is one of those primary colors,
it is not a product of the other two. Red plus green actually yields
yellow.

Brooks

>
>
> BUFDRVR
>
> "Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
> everyone on Bear Creek"

[Ralph Savelsberg]

BUFDRVR wrote:

>>Green + Red = Blue???
>>Mind boggles.
>>
>
> hmm, doesn't it? I have an idiglo Timex that has a blue light, I was told by
> the NVG instructor in my squadron that it would work well enough, but would
> have been better if it were green. He then gave me that exact line I gave you
> above, anything with shades of red in it will tend to wash out NVGs. Anyone out
> there have a clue better than mine? Any color spectrum experts?
>
>
> BUFDRVR
>
> "Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
> everyone on Bear Creek"
>

The green plus red is blue boggles my mind.

Still,

I wouldn't call myself a colour spectrum expert, but I'll give it a try:
The NVGs are most sensitive to light at the low frequency/ long
wavelength end of the visual spectrum, i.e. the red end of the spectrum
(and unlike the human eye even is sensitive to somewhat lower
frequencies in the IR range).
Green is associated with higher frequencies/smaller wavelengths than
red. A red light of a certain intensity produces a far stronger response
in the NVG than a green light of similar intensity would, since green
lies further away from the wavelength range to which the NVGs are most
susceptible. Pretty straightforward.
As for the blue, this is associated with even higher frequencies/smaller
wavelengths than the green, so it should be even less visible, which
gives no explanation whatsoever for why green would work better than
blue, unless with blue the worry would be that you wouldn't bee able to
see that at all, while wearing your NVGs.

Regards,
Ralph Savelsberg

[KeithK]

In article >,
(Kevin Brooks) wrote:


>
> I believe what he was referring to is the fact that red, green, and
> blue are *the* primary colors.
Er, isn't that red, green, and yellow?

[Ralph Savelsberg]

KeithK wrote:

> In article >,
> (Kevin Brooks) wrote:
>
>
>
>>I believe what he was referring to is the fact that red, green, and
>>blue are *the* primary colors.
>>
> Er, isn't that red, green, and yellow?
>
There is no such thing as "the primary" colours.


Colour is a very subjective thing.

If you're dealing with paint it would be red, blue and yellow (or Cyan,
Magenta and Yellow)
If dealing with light the most commonly used one would be red, blue and
green (RGB)

The human eye contains two different types of light receptive cells:
so-called cones and rods. Cones are used in light with relatively high
intensities and are responsible for colour vision. Visible light is only
a very small part of the electromagnetic spectrum, between 380 and 700
nm. Light of a certain spectral wavelength appears to us as a colour,
but light from a single wavelength is not the only way to create the
sensation of that particular colour. Different spectral distributions
can produce an indistinguishable colour sensation. The commonly accepted
theory for how colour vision works is that the cones in the human eye
contain three different pigments, with three different absorption
spectra: a pigment most sensitive to light around 450 nm (blue), one
most sensitive to light with a wavelength of 550 nm (green/yellow) and
one most sensitive near 570 nm (yellow/orange). That is why combinations
of three primaries, for instance red, green and blue can be used to
create pretty much every colour sensation.

A fine explanation of colour vision can be found in `The Feynman
Lectures on Physics', by Richard Feynman, of which every self-respecting
library should have at least one copy.

Regards,
Ralph Savelsberg

[Peter Stickney]

In article >,
(KeithK) writes:
> In article >,
> (Kevin Brooks) wrote:
>
>
>>
>> I believe what he was referring to is the fact that red, green, and
>> blue are *the* primary colors.
> Er, isn't that red, green, and yellow?

Well, that would be inks, instead of light. And it would be Red,
Blue, and Yellow. (Actually, it would be Magenta, Cyan, and Yellow,
as in the CMYK notation used by printers to define colors.

Light is Red, Green, Blue, as in an RGB computer monitor.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

[Kevin Brooks]

Ralph Savelsberg > wrote in message >...
> KeithK wrote:
>
> > In article >,
> > (Kevin Brooks) wrote:
> >
> >
> >
> >>I believe what he was referring to is the fact that red, green, and
> >>blue are *the* primary colors.
> >>
> > Er, isn't that red, green, and yellow?
> >
> There is no such thing as "the primary" colours.

Well, most generally consider RGB to be the primary colors of light,
and that is the subject under discussion here.

>
>
> Colour is a very subjective thing.
>
> If you're dealing with paint it would be red, blue and yellow (or Cyan,
> Magenta and Yellow)

But we are not dealing with paint (for which the proper selection is
the latter, IIRC).

> If dealing with light the most commonly used one would be red, blue and
> green (RGB)

Exactly.

Brooks

<snip>

[James Hart]

Clark wrote:
> "James Hart" > wrote in
> news:born99$1hucui$2@ID- 76251.news.uni-berlin.de:
>
>> BUFDRVR wrote:
>>>> I'm thinkin that with NVS, the lights are blue? Not sure, but it
>>>> would make sense. I know before NVS came out the formation lights
>>>> were all green, but this would overdrive and blind NVG's.
>>>
>>> Actually Green lighting is better than Blue lighting for NVGs.
>>> Anything with shades of Red light (Green + Red = Blue) will wash out
>>> the NVGs.
>>
>> Green + Red = Blue???
>> Mind boggles.
>>
> No boggle, just an alternate color reality.
> :-)

Makes for some purdy camo schemes I'd guess .

--
James...
http://www.jameshart.co.uk/

[BUFDRVR]

>The green plus red is blue boggles my mind.
>
>Still,
>
>I wouldn't call myself a colour spectrum expert, but I'll give it a try:
>The NVGs are most sensitive to light at the low frequency/ long
>wavelength end of the visual spectrum, i.e. the red end of the spectrum
>(and unlike the human eye even is sensitive to somewhat lower
>frequencies in the IR range).
>Green is associated with higher frequencies/smaller wavelengths than
>red. A red light of a certain intensity produces a far stronger response
>in the NVG than a green light of similar intensity would, since green
>lies further away from the wavelength range to which the NVGs are most
>susceptible. Pretty straightforward.
>As for the blue, this is associated with even higher frequencies/smaller
>wavelengths than the green, so it should be even less visible, which
>gives no explanation whatsoever for why green would work better than
>blue, unless with blue the worry would be that you wouldn't bee able to
>see that at all, while wearing your NVGs.

Wow, this thread has gotten good, imagine that I'm actually learning here.
Unfortunately, I obviously misunderstood the NVG experts words, I thought he
said blue light was closer to the red spectrum than green, but if you're
correct (as well as another poster who posted the exact frequencies for each
color...impressive), I must have misunderstood. Anyway, he was correct, my blue
indiglo watch washed out my NVG's, if only slightly, while the green light of
similar intensity did not.


BUFDRVR

"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"

[Regnirps]

(Kevin Brooks) wrote:

>> If you're dealing with paint it would be red, blue and yellow (or Cyan,
>> Magenta and Yellow)

RGB corresponds to the color detectors in the retina.

With paint, as in having it mixed at the hardware store, one uses a bunch of
colors, like 10 or 12 to form a polygon in the color space and give a much
larger pallet of colors. Just RGB or CMY gives a triangle and leaves out a lot
of the perceivable colors. See any chromaticity diagram (which is three
dimmensional and usually shown as two with shading for the third).

It is possible to "see" colors that do not exist in the electromagnetic
spectrum, like brown. Likewise, the orange from red+yellow is a product of the
brain and retina as opposed to an orange spectral line from a sodium lamp. They
look the same to us but a simple filter will show the difference.

So, what and NVG will react to can be auite different from what the eye alone
will react to.

Most of modern color/brain theory comes from work by Land who found ways to
"fool" the brain into seeing full color with just two colors in the projection.

Photographers talk about addititive and subtractive colors depending on whether
a process uses primary dyes or filtering gels.

>But we are not dealing with paint (for which the proper selection is
>the latter, IIRC). >><BR><BR>

-- Charlie Springer

The Feynmann is of course a very good reference.

[Steve Hix]

In article >,
(KeithK) wrote:

> In article >,
> (Kevin Brooks) wrote:
>
>
> >
> > I believe what he was referring to is the fact that red, green, and
> > blue are *the* primary colors.
> Er, isn't that red, green, and yellow?

Red, green, and blue are the additive primary colors. You can get
anything from combining those. (See your color monitor.)

The subtractive primary colors are cyan, magenta, and yellow; the three
(with black to help improve contrast) get you all the colors that you'll
find in, say, National Geographic magazine.

[John Keeney]

"KeithK" > wrote in message
...
> In article >,
> (Kevin Brooks) wrote:
>
>
> >
> > I believe what he was referring to is the fact that red, green, and
> > blue are *the* primary colors.
> Er, isn't that red, green, and yellow?

Actually, red, green blue are "the primary colors of light" but
red, yellow and blue serve the same purpose for pigments.

The red, green blue thing originates in the human eye. In a "normal,
healthy eye" there are four types of receptors: one type is most
sensitive in the red region of the spectrum, one in the green, one
in the blue and one (that provides night vision) is sensitive across
a the great swath of the visible spectrum up into the ultra violet.
None of the types have exactly sharp cut offs in sensitivity and in
fact the color cells have a good deal of over lap in their sensitivities.
It's because of this over lap that mixing the "primary colors" fools
the eye into seeing the infinite colors and shades that lie between.

[Kevin Brooks]

(Regnirps) wrote in message >...
> (Kevin Brooks) wrote:
>
> >> If you're dealing with paint it would be red, blue and yellow (or Cyan,
> >> Magenta and Yellow)

You are responding to the wrong poster--I did not say the above.

Brooks

>
> RGB corresponds to the color detectors in the retina.
>
> With paint, as in having it mixed at the hardware store, one uses a bunch of
> colors, like 10 or 12 to form a polygon in the color space and give a much
> larger pallet of colors. Just RGB or CMY gives a triangle and leaves out a lot
> of the perceivable colors. See any chromaticity diagram (which is three
> dimmensional and usually shown as two with shading for the third).
>
> It is possible to "see" colors that do not exist in the electromagnetic
> spectrum, like brown. Likewise, the orange from red+yellow is a product of the
> brain and retina as opposed to an orange spectral line from a sodium lamp. They
> look the same to us but a simple filter will show the difference.
>
> So, what and NVG will react to can be auite different from what the eye alone
> will react to.
>
> Most of modern color/brain theory comes from work by Land who found ways to
> "fool" the brain into seeing full color with just two colors in the projection.
>
> Photographers talk about addititive and subtractive colors depending on whether
> a process uses primary dyes or filtering gels.
>
> >But we are not dealing with paint (for which the proper selection is
> >the latter, IIRC). >><BR><BR>
>
> -- Charlie Springer
>
> The Feynmann is of course a very good reference.

[Tarver Engineering]

"BUFDRVR" > wrote in message
...
> >Green + Red = Blue???
> >Mind boggles.
>
> hmm, doesn't it?

Green is yellow + blue

[John Mullen]

"Tarver Engineering" > wrote in message
...
>
> "BUFDRVR" > wrote in message
> ...
> > >Green + Red = Blue???
> > >Mind boggles.
> >
> > hmm, doesn't it?
>
> Green is yellow + blue
>
>

Go back to sleep, John

:)

John

[Tarver Engineering]

"John Mullen" > wrote in message
...
> "Tarver Engineering" > wrote in message
> ...
> >
> > "BUFDRVR" > wrote in message
> > ...
> > > >Green + Red = Blue???
> > > >Mind boggles.
> > >
> > > hmm, doesn't it?
> >
> > Green is yellow + blue

> Go back to sleep, John

Actually, we make NVG repeaters for Aussie rotary wings. There is quite a
bit of extra effort required for the timing of the lighting circuit and
filtering; even with HP NVG green LED arrays.

Red is bad, green is good, but not just any green.

[Ralph Savelsberg]

Regnirps wrote:

> (Kevin Brooks) wrote:
>
>
>>>If you're dealing with paint it would be red, blue and yellow (or Cyan,
>>>Magenta and Yellow)
>
>
> RGB corresponds to the color detectors in the retina.
>
> With paint, as in having it mixed at the hardware store, one uses a bunch of
> colors, like 10 or 12 to form a polygon in the color space and give a much
> larger pallet of colors. Just RGB or CMY gives a triangle and leaves out a lot
> of the perceivable colors. See any chromaticity diagram (which is three
> dimmensional and usually shown as two with shading for the third).
>
Which is why painting is an art. However, pretty much every ink-jet
printer uses CMY + black. Higher quality ink-jet printers use about six
different colours.
> It is possible to "see" colors that do not exist in the electromagnetic
> spectrum, like brown.
Yes, brown isn't spectral colour.
Likewise, the orange from red+yellow is a product of the
> brain and retina as opposed to an orange spectral line from a sodium lamp. They
> look the same to us but a simple filter will show the difference.
>
Sure, a combination of two primaries can lead to the same sensation as a
specific spectral colour.

> So, what and NVG will react to can be auite different from what the eye alone
> will react to.
>
> Most of modern color/brain theory comes from work by Land who found ways to
> "fool" the brain into seeing full color with just two colors in the projection.
>
> Photographers talk about addititive and subtractive colors depending on whether
> a process uses primary dyes or filtering gels.
>
>
>>But we are not dealing with paint (for which the proper selection is
>>the latter, IIRC). >><BR><BR>
>
>
> -- Charlie Springer
>
> The Feynmann is of course a very good reference.
>
We're making the same point here. Different primaries can be used in
different combinations to produce the same colour sensation on your retina.

Regards,
Ralph Savelsberg

[Tarver Engineering]

"BUFDRVR" > wrote in message
...
> >The green plus red is blue boggles my mind.
> >
> >Still,
> >
> >I wouldn't call myself a colour spectrum expert, but I'll give it a try:
> >The NVGs are most sensitive to light at the low frequency/ long
> >wavelength end of the visual spectrum, i.e. the red end of the spectrum
> >(and unlike the human eye even is sensitive to somewhat lower
> >frequencies in the IR range).
> >Green is associated with higher frequencies/smaller wavelengths than
> >red. A red light of a certain intensity produces a far stronger response
> >in the NVG than a green light of similar intensity would, since green
> >lies further away from the wavelength range to which the NVGs are most
> >susceptible. Pretty straightforward.
> >As for the blue, this is associated with even higher frequencies/smaller
> >wavelengths than the green, so it should be even less visible, which
> >gives no explanation whatsoever for why green would work better than
> >blue, unless with blue the worry would be that you wouldn't bee able to
> >see that at all, while wearing your NVGs.
>
> Wow, this thread has gotten good, imagine that I'm actually learning here.
> Unfortunately, I obviously misunderstood the NVG experts words, I thought
he
> said blue light was closer to the red spectrum than green, but if you're
> correct (as well as another poster who posted the exact frequencies for
each
> color...impressive), I must have misunderstood. Anyway, he was correct, my
blue
> indiglo watch washed out my NVG's, if only slightly, while the green light
of
> similar intensity did not.

Green light is the best way to blind NVGs, as that is the light they are
most sensitive to. Quite a bit of care is required to produce the correct
frequency of green light, for an NVG display to be readily readable.

[BUFDRVR]

>Green light is the best way to blind NVGs

I hope you mean red. With NVGs on, I can see a glow from a red light turned on
*behind me*. No matter how bright a green light is, it will not wash out NVGs
anymore than red light.


BUFDRVR

"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"

[redc1c4]

BUFDRVR wrote:
>
> >Green light is the best way to blind NVGs
>
> I hope you mean red. With NVGs on, I can see a glow from a red light turned on
> *behind me*. No matter how bright a green light is, it will not wash out NVGs
> anymore than red light.

nope, that's Tarver for ya.... forged in the "D-U-M-B" position.

redc1c4,
ask him about the "strakes" on the F/A 22. %-)
--
"Enlisted men are stupid, but extremely cunning and sly, and bear
considerable watching."

Army Officer's Guide