[For example](https://www.nasa.gov/sites/default/files/styles/side_image/public/thumbnails/image/s84-27018.jpg?itok=iwWtIpvc)
In: Earth Science
Take a picture of a streetlight at night and check out the stars in the background.
To properly expose an image onto a CCD (digital) or film the amount of light has to be properly balanced. Too much and things are overexposed and blown out. Too little and it’s all dark. Right in between gets you a balance of both. Just right in between means you can’t expose the brightest things and the darkest things at the same time. There are compromises. Shadow detail and stars are the compromises.
Unrelated but what’s going on in the image above? I always thought they’re tethered to the ship not just floating around solo like that when out on space walks.
Spacewalks take place at daytime, and even at night they use powerful spotlights that make it as bright as day. You may be fooled because there is no blue sky above them but except for that the conditions are the same as a bright summer day here on the ground. So in order to be able to capture anything on camera they have to adjust them to daytime conditions. And with these settings the dim light from the stars is no longer visible. It is even hard to see the Moon with those settings, just like the Moon is very hard to see on daytime images taken on the ground.
That’s just to do with the camera settings. If you set the exposure to long enough that you’ll see the stars, then everything in the foreground (astronauts, space shuttles, etc) will be really bright and washed out.
In these photos, they don’t want you to see the stars, they want you to see the astronauts.
You’re probably comparing these photos to what stars you’d see at night time. But these photos aren’t taken at night, they’re in direct sunlight. The stars are visible but they’re much dimmer than you might expect because of the sunlight, and that’s why you’d need pretty long exposure times to have them show up on camera.
You can also try this yourself. Next time you’re out at night, take a photo with your phone and see if the stars that you can see are visible on the photo. They probably won’t be, except for maybe the brightest stars. Obviously, the cameras used for space photography are more powerful than your phone camera, but it’s the same principle.
I’m just guessing, but it’s probably because the camera is focused on a bright object or there’s too much ambient light. Similar to how you can’t see in the dark for a while after leaving a bright room or how you can see less stars in the city than in the country.
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