The TMT. It's dynomite.
Near the center of Pasadena, California, a team of scientists, engineers, and project specialists is busily planning and designing what eventually will become the most advanced and powerful optical telescope on Earth. When completed later this decade, the Thirty Meter Telescope (TMT) will enable astronomers to study objects in our own solar system and stars throughout our Milky Way and its neighboring galaxies, and forming galaxies at the very edge of the observable Universe, near the beginning of time.
http://www.tmt.org/science-case
The 30-meter aperture permits the telescope to focus more sharply than smaller telescopes by using the power of diffraction of light. The large aperture also collects more light than smaller scopes, allowing images of fainter objects. TMT will therefore reach further and see more clearly than previous telescopes by a factor of 10 to 100 depending on the observation.
In addition to providing nine times the collecting area of the current largest optical/infrared telescopes (the 10-meter Keck Telescopes), TMT will be used with adaptive optics systems to allow diffraction-limited performance, i.e., the best that the optics of the system can theoretically provide. This will provide unparalleled high-sensitivity spatial resolution more than 12 times sharper than what is achieved by the Hubble Space Telescope. For many applications, diffraction-limited observations give gains in sensitivity that scale like the diameter of the mirror to the fourth power, so this increase in size has major implications.