Historical Electronics Museum to Host Reunion of Apollo 11 Lunar Camera Team on 36th Anniversary of Historic Moon Landing

Just realized that this is just a short drive from here - I might try to go myself.

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Everything I need to know I learned through Googling.

So, are they going to have a good laugh at how they fooled the world? I'd expect there'll be a lot of very expensive cars, bought with all of that hush money.

Well, they fooled a lot of people into thinking they were using an ordinary vidicon instead of a special, top-secret low-light pickup tube. No, seriously.

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"Facts are stubborn things." --John Adams
Clavius Moon Base

Sssshhhh... Don't mention the secret camera tube. We cannot let that technology fall into the wrong hands.

I think it's hilarious that David Percy gets it all backwards.

He says the TV camera was fitted with a "low-light" lens for shadow television photography. He then wonders why the still cameras and film cameras didn't also require those lenses. In fact, the lens used to show Armstrong on television in the shadow of the lunar module was the normal lens. The vidicon was a low-light device. The "special" lens was the one put on afterwards for photgraphy in sunlight. It has an aperture of something like f/60 to stop the light down to the point where the vidicon can see it.

And that's part of the reason behind the crapulence of Apollo 11 television images -- the vidicon was chosen for its low-light capability, which means you sacrifice picture quality overall.

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"Facts are stubborn things." --John Adams
Clavius Moon Base

Wasn't the same tube used for the Apollo 12 and 13 TV cameras?

Yes, at least the same general class of tube (SEC vidicon). The color filters reduced the amount of light hitting the image tube's faceplate.

F60 eh? Gotta think that lens got a bit diffraction limited....

When I think of a "low-light" lens, I think of a lens that is extemely efficient allowing maximum light to fall on the face plate. A low light camera operates so you can see in ... low light.

So I would think that NASA's camera was special in that it and the lens was designed to operate in high light. Doesn't that make it a high light device?

Are we talking semantics here or is there something I'm not getting?

RBG

The latter. The camera had to operate in low light because the "first step" images were taken in the shadow of the LM. This was, of course, known to mission planners beforehand.

The vidicon was therefore a low-light tube, and used a normal lens for the historic (but poorly illuminated) "one small step" scene. Then a stop-down lens was substituted for the later fully-sunlit scenes.

Well, Jay's explanation makes perfect sense now that I re-read it. A synapse must have shorted out in my brain. Perhaps I was thinking there were two cameras involved or something. Anyway, disregard my above.

RBG

An interesting tidbit for how sensitive those SEC vidicon tubes were is that typical room light is about 50 times brighter than the illumination that the tube could handle without being damaged. All the lenses built for the camera had to reduce the light hitting the tube's faceplate, and the techs on the ground had to be careful not to operate the camera without a lens (never mind pointing it into the Sun!)

In my library I have the checkout and test procedures for that camera. It's littered with warnings about the sensitivity of the image sensor.

__________________
"Facts are stubborn things." --John Adams
Clavius Moon Base

So how did Neil change lenses without destroying the sensor? He didn't exactly have a darkroom handy where he could do the job...

The 1-foot-candle maximum spec was for an indefinite period of time. I presume one could get away with a quick lens change.