The Kepler photometer is the main instrument on NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

's Kepler spacecraft.

It is a Schmidt telescope (95 cm clear aperture, 140 cm mirror) with an array of 42 2200x1024 CCDs

Charge-coupled device

A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...

 in the focal plane; each CCD is flat, but they are mounted on a curved structure to account for the curved focal plane. The CCDs are not abutting, so the focal plane is not entirely covered, but since the mission's goal is to observe a sample of stars, this doesn't matter.