Photographing long exposure stars from the ISS?
Astronaut Scott Kelly is known for uploading photos of his stay at the ISS to social networks (Twitter, Instagram), among them he has several photographs in which the stars are observed
http://www.pcmag.com/...ear-in-s/1" class='ext_link'>http://www.pcmag.com/...ear-in-s/1
https://twitter.com/...0549659648" class='ext_link'>https://twitter.com/...0549659648
It is known that he uses a Nikon D4 camera with the following details:
Lens - 70-200mm
Aperture - f / 22.0
Focal length - 200mm
Exposure time - 1/640 seconds
ISO-800
So how can you photograph stars like this, if the ISS is at a high speed orbiting Earth and without using a motor drive / electronic support that is normally used on Earth to track the stars?
Added (1). I did wrong the question, I know that the exposure time is adjustable. I put those data as reference. My question was, if the ISS moved so fast, how could they take high exposure photos without an electronic support for tracking stars.
Astronaut Scott Kelly is known for uploading photos of his stay at the ISS to social networks (Twitter, Instagram), among them he has several photographs in which the stars are observed
http://www.pcmag.com/slideshow/story/335661/57-magnificent-photos-from-astronaut-scott-kelly-s-year-in-s/1
https://twitter.com/StationCDRKelly/status/771038590549659648
It is known that he uses a Nikon D4 camera with the following details:
Lens - 70-200mm
Aperture - f / 22.0
Focal length - 200mm
Exposure time - 1/640 seconds
ISO-800
So how can you photograph stars like this, if the ISS is at a high speed orbiting Earth and without using a motor drive / electronic support that is normally used on Earth to track the stars? Because 1/640 seconds is a very short exposure. To capture a deep space object from earths surface takes a much longer F/D a much larger aperture, and exposure into minutes.
Much of Cmndr Kelly's images are terrestrial. Using the same camera and settings, one can photo the ISS and show enough detail to identify it.
If you search the web, there area number of photos that capture the ISS silhouetted against objects like the moon and the sun.
Keep in mind, aboard ISS there's no atmosphere that causes distortion in images, and even modern photography can correct terrestrial images taken of deep space objects coming close to matching HST. In other words, he didn't use long exposures, unless you count 1/640 th of a second as long. The settings you list would not show stars. I would guess that sunset photo was taken at large aperture for a second or more. If the camera was mounted, the motion of the ISS wouldn't cause enough motion to show star trails at that image size. Note that his pictures of Earth in daylight don't show stars, indicating that a variety of exposures were used. You can't photograph stars with those settings. But I don't think they're stars - they're clustered in front of the sun, and the ones seen through \Earth's atmosphere aren't dimmed. I think they might be ice crystal or droplets dumped from the ISS. 1/640 is not a long exposure, even at ISO 800. A quick look at the Twitter and PC images reveals no information about camera settings, so where did you get them from and why do you imagine he used them for all the photos?
In other words, he didn't use long exposures, unless you count 1/640 th of a second as long.
The settings you list would not show stars. I would guess that sunset photo was taken at large aperture for a second or more. If the camera was mounted, the motion of the ISS wouldn't cause enough motion to show star trails at that image size. Note that his pictures of Earth in daylight don't show stars, indicating that a variety of exposures were used.
You can't photograph stars with those settings. But I don't think they're stars - they're clustered in front of the sun, and the ones seen through \Earth's atmosphere aren't dimmed. I think they might be ice crystal or droplets dumped from the ISS.
1/640 is not a long exposure, even at ISO 800. A quick look at the Twitter and PC images reveals no information about camera settings, so where did you get them from and why do you imagine he used them for all the photos?