mattie_shoes
stacking
Astrophotography is generally harder than regular photography... You've got light-pollution from cities, and miles and miles and miles of air between you and your subject, the subjects are usually incredibly dim, and they move across the sky. This means that for an astrophotographer, the most expensive piece of equipment may not be the telescope or camera... It may be the mount. The mount has to track smoothly and accurately across the sky for minutes or hours as the object moves across the sky.
Astrophotographers do have one very large advantage over regular photographers though... Anything outside our solar system really doesn't change much. You could take pictures of the ring nebula, wait a year, and take some more, and barring a nearby supernova, you'd never be able to tell which was which.
One common technique used by real astrophotographers is called stacking. They take a bunch of pictures of the same object, and stack them together to pull out details that are not clearly visible in any one picture. This means their mount doesn't have to be quite as accurate, since each picture is of a shorter duration. It also helps to get rid of problems inherent to digital cameras like hot pixels and cold pixels.
To play around with this idea, I took about 100 pictures of the moon (no telescope, just holding the camera). Then I fed them all into a program called registax and these were the results for 1, 2, 4, etc. images. This was just a very low-tech experiment but I think it shows the advantage, and also the diminishing returns on a per-image basis.
stacking
Astrophotography is generally harder than regular photography... You've got light-pollution from cities, and miles and miles and miles of air between you and your subject, the subjects are usually incredibly dim, and they move across the sky. This means that for an astrophotographer, the most expensive piece of equipment may not be the telescope or camera... It may be the mount. The mount has to track smoothly and accurately across the sky for minutes or hours as the object moves across the sky.
Astrophotographers do have one very large advantage over regular photographers though... Anything outside our solar system really doesn't change much. You could take pictures of the ring nebula, wait a year, and take some more, and barring a nearby supernova, you'd never be able to tell which was which.
One common technique used by real astrophotographers is called stacking. They take a bunch of pictures of the same object, and stack them together to pull out details that are not clearly visible in any one picture. This means their mount doesn't have to be quite as accurate, since each picture is of a shorter duration. It also helps to get rid of problems inherent to digital cameras like hot pixels and cold pixels.
To play around with this idea, I took about 100 pictures of the moon (no telescope, just holding the camera). Then I fed them all into a program called registax and these were the results for 1, 2, 4, etc. images. This was just a very low-tech experiment but I think it shows the advantage, and also the diminishing returns on a per-image basis.