How do astronomers take a picture of the galaxy?

Question

How do they take CLEAR and VIVID pics of other celestial bodies if even Pluto, they can only take a blurred or unclear pictures? How did they get the picture of andromeda galaxy, supernovas, nebulas, etcs? I really don't get it

Answer 1

long exposure, the more you expose the film to a faint light the more shows up, also Pluto doesn't emit light, only reflects.

Answer 2

There are two issues here. First is that many deep space objects, especially galaxies generate their own light. They are dim, to be sure, but they are light emitters. Pluto shines by reflected light. There are, of course, many nebula that are reflection nebula, so they, too, shine by reflected light. That brings us to the second point.

Despite their dimness, most deeps space objects have large angular size. Consider Andromeda, for example. It goes largely unnoticed by most people because it is so dim, and yet it covers more than twice the sky than does the full moon! On the other hand, Pluto is tiny in comparison. Andromeda is about 190' x 60' arc minutes, and Pluto is about .015" arc seconds (remember, there are 60 arc seconds in an arc minute). The moon by comparison is about 30' arc minutes, say, half a degree in size.

HTH

Charles

Answer 3

From the earth, to get a good picture of a galaxy you need to take a long exposure to reveal the faint detail. For this you generally need a telescope, a equatorial mount and a camera of some kind. The equatorial mount is used to track the object as it moves across the night sky. Generally exposure times vary from a few minutes to several hours(!). You can see example of equipment used for taking celestial pictures listed here: http://astroads.com

Answer 4

The Andromeda galaxy is three degrees across---more than 40 times the area of the Moon. It's just faint, and a deep exposure with a large telescope brings out lots of detail.

Pluto is less than one second of arc across---less than one-millionth the area of the Moon. It's also really faint.

Answer 5

They are using x-ray telescopes like Chandra which orbits the earth.

Instead of staring at one relatively small part of the sky for a long time, as with the Chandra Deep Fields -- two of the longest exposures obtained with the observatory -- and other concentrated surveys, this strategy employed a technique that scanned a much bigger portion with shorter exposures. Since the biggest black holes power the brightest AGN, they can be spotted at vast distances, even with short exposures.

Answer 6

long exposure photography allows faint light to collect on the film or digital camera. pluto is so small and telescopes cant "resolve" it. andromeda as viewed from earth is about the same size as the full moon. so it all has to do with apparent size as viewed from earth!!!! hope this helps. look up how telescopes work and you might get a better understanding of "angular resoloution"!!! good luck!!!!!

Answer 7

Galaxies are really big. There are billions of stars compressed into those photos you see. You cannot even make out the detail of a star in the galaxy. Pluto is incredibly small (that is why the demoted its planet status).

Answer 8

with CCD imaging you will probable take a thousand images, and the software will through away 1/4 of the images, and stack the rest. If you looked at just one image , it wouldn't be that impressive. But the more images you have , the better.With film, you need long exposure. with ccd imaging, you need many short exposures.

Answer 9

http://www.answers.com/topic/astrophotography

Answer 10

"Demonus" gave you the most correct answer.