Space based
A Schmidt telescope was at the heart of the Hipparcos satellite from the European Space Agency (1989–1993). This was used in the Hipparcos Survey which mapped the distances of more than a million stars with unprecedented accuracy - this included 99% of all stars up to magnitude 11. The spherical mirror used in this telescope was extremely accurate; if scaled up to the size of the Atlantic Ocean, bumps on its surface would be about 10 cm high.
The Kepler photometer, mounted on the Kepler probe, and orbiting since March 2009, is the largest Schmidt camera launched into space.