given the success of the HST, why do astronomers continue to build bigger and bigger Earth-based telescopes?

Question

jamesj · Answer

There's still a lot to discover and even with an optical telescopes that don't have the angular resolution of the Hubble, we can discover things. In any case, there is a successor to Hubble in the works: http://www.jwst.nasa.gov/comparison.html ..and the major earth-bound telescopes that are being developed now are not optical. For example: http://www.ska.gov.au/Pages/default.aspx

anonymous · Answer

Thanks James seems like a good enough reason to continue building them, can u tell me what the celestial equator is?

jamesj · Answer

Sure: http://en.wikipedia.org/wiki/Celestial_equator

anonymous · Answer

Three reasons come to mind:

(1) Because it costs of order $5,000 per pound to put things in orbit, and it's slow and incredibly expensive to service them there.

(2) Because they have to be much more robust to survive the harsh environment of space.

(3) Because the atmosphere doesn't interfere at all with radio astronomy, and for optical and IR the main problems can often be addressed these days by adaptive optics.  (For UV and X-rays, you still need to be in orbit.)