Most people are interested in a glamorized depiction of space - the movies,
the launches, the astronauts. But there are still a lot of misconceptions, and people
often don't understand what they're seeing in real videos from space. One of
the most frequent questions is: "Where are the stars?"
It's true - watch almost any video from space that isn't a time-lapse. You won't
see any stars. From America's first spacewalk in 1965 by astronaut Ed White
to footage from the surface of the Moon during the Apollo missions
to helmet cam videos from numerous astronaut EVA's
and NASA's High Definition Earth Viewing livestream from the International Space
Station. The Moon is visible, if a bit dim, but the stars are not.
Even the $20,000 Red Epic Dragon 6K digital cinema camera - while producing
brilliant images of Earth - still shows only pitch blackness beyond.
So, where are the stars? We know they're up there. We can see them with our own
eyes at night. Some conspiracy-minded people like to claim that the lack of
stars proves that all space videos are fake. This is nonsense of course. The real
answer is simple: cameras can't properly expose both bright and dim objects at
the same time. Okay, so here we are outside on this beautiful sunny North
American day in a backyard that may or may not be mine, and we're going to
conduct a test. Right now it's daytime, and here we have a subject: a little taco
eating unicorn that we're going to take a picture of. Then we're going to take
another picture at night using the same camera settings, and see if we can see
any stars. When the camera is properly exposed for daytime it's going to be
too dark for nighttime. All right, so here I've got my Nikon D90 trusty old digital
SLR camera. I have it in program mode, meaning the camera is going to decide
the exposure. It has the stock 18-105 mm lens on it. Okay, so let's take
our photo. And the auto metering in the camera set the exposure value to 1/640th
of a second at f/13. So just for kicks I'm going to manually change the
exposure settings on the camera. Let's say 2 seconds at f/4. Now I'm going to
take the same picture using the 2-second exposure.
Yeah, it's just a pure white screen. It's completely overexposed, because there's
way way too much light out here for a 2-second exposure. Next we're going to
take some photos using the same settings at night, and see what happens.
And here we are again. It's a nice clear night, a slightly brisk 42 degrees
Fahrenheit, and we're back outside with our taco munching unicorn. Except it is
now dark, as you can see. I'm illuminated by the light on the back of my house.
Let's use the same settings that we used earlier today when we took this picture.
So I have set my camera for 1/640th of a second f/13, and we're going to take a
photo. Okay, and as I suspected you see absolutely nothing. Nothing at all.
I'm going to do what I did before, and let the camera decide what exposure
settings to use. I'm going to set it to program mode. Auto metering is suggesting
settings of 1/25th of a second at f/3.5.
Okay now if we look at that,
you can see the background is pitch black, but the foreground looks fine.
I'm now going to use the same settings to take a picture of the clear night sky,
where there's a Moon. I do see some of the brighter stars. I cannot see anything
through my viewfinder. But I'm gonna go ahead and take the picture.
Not surprisingly, it is pitch black. The other photo that I took earlier where it was
completely overexposed... 2 seconds at f/4... set those. What we get is, the unicorn
is horribly overexposed. Some of the background is okay, but the subject
itself - the unicorn - is completely blown out. Just for comparison's sake let's
shoot the Moon again, because I can see Mars off to its right. We see the moon is
overexposed, and if we zoom out a little bit: Mars. And it looks like a smudge
because again it was a 2-second exposure, handheld, not on a tripod.
But the point is, in order to see stars and planets you need very high light
sensitivity, or a long exposure. In other words, in order to get a proper exposure
- even on an illuminated subject - at night, you need camera settings that will show
you absolutely nothing if you're looking at the night sky. And there you have it.
That's a practical demonstration, easy to do with just a camera, that demonstrates
why you cannot see stars in videos from space.
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