Today I thought we could have a look at something that I suppose is often little considered when looking at these pic of the day posts; the very thing that gives us a lot of the images, so today I bring you the Hubble Space Telescope.
Why put observatories in space? Most telescopes are on the ground. On the ground, you can deploy a heavier telescope and fix it more easily. The trouble is that Earth-bound telescopes must look through the Earth's atmosphere. First, the Earth's atmosphere blocks out a broad range of the electromagnetic spectrum, allowing a narrow band of visible light to reach the surface. Telescopes which explore the Universe using light beyond the visible spectrum, such as those onboard the Chandra X-ray Observatory need to be carried above the absorbing atmosphere. Second, the Earth's atmosphere blurs the light it lets through. The blurring is caused by varying density and continual motion of air. By orbiting above the Earth's atmosphere, the Hubble Space Telescope, pictured above, can get clearer images. In fact, even though HST has a mirror 15 times smaller than large Earth-bound telescopes, it can still resolve finer details. A future large optical telescope in space is planned.
A higher resolution image is available here this image is a 299K Jpeg image.
Previous Pic Of The Day posts
22nd Dec 02
21st Dec 02
20th Dec 02
19th Dec 02
18th Dec 02
17th Dec 02
16th Dec 02
Why put observatories in space? Most telescopes are on the ground. On the ground, you can deploy a heavier telescope and fix it more easily. The trouble is that Earth-bound telescopes must look through the Earth's atmosphere. First, the Earth's atmosphere blocks out a broad range of the electromagnetic spectrum, allowing a narrow band of visible light to reach the surface. Telescopes which explore the Universe using light beyond the visible spectrum, such as those onboard the Chandra X-ray Observatory need to be carried above the absorbing atmosphere. Second, the Earth's atmosphere blurs the light it lets through. The blurring is caused by varying density and continual motion of air. By orbiting above the Earth's atmosphere, the Hubble Space Telescope, pictured above, can get clearer images. In fact, even though HST has a mirror 15 times smaller than large Earth-bound telescopes, it can still resolve finer details. A future large optical telescope in space is planned.
A higher resolution image is available here this image is a 299K Jpeg image.
Previous Pic Of The Day posts
22nd Dec 02
21st Dec 02
20th Dec 02
19th Dec 02
18th Dec 02
17th Dec 02
16th Dec 02