Astrophotography

So tonight I was speaking to vivianteddybear about telescopes. I was having a very difficult time understanding why one would not want to have a variety of telescopes available—some narrow field, some wide field, and so on—and was horrified that, according to her, the way astronomers deal with "I want to look at Supernova X" is they throw the rest of the telescope's image away.

It literally did not occur to me at all that, because of atmospheric disturbances, it is not actually possible to image stellar objects to a resolution of better than about 0.4 arcseconds, which you can achieve with about a 12" telescope mirror. The reason why large mirror narrow field telescopes do not exist is because there is no point; you will not actually be able to get any better resolution than a similarly equipped wide-field telescope.

To restate, the problem is that the optics and the image recording medium are higher fidelity than the universe, or at least the part of the universe we can see through our atmosphere, and so it's perfectly okay to throw away some of the resolution.