30 METER telescope being built now:

http://phys.org/news/2013-08-mission-world-advanced-telescope-major.html

It will take a while to finish, 2022, on Mauna Kea near the present Keck. It will have three times the resolution as the Keck! A lot more resolution than the Hubble scope.

I can't wait!

I bet there is already a 5+ year waiting list to get time on it.