Placing a CCD array at the prime focus of a telescope or observatory is a surefire way to get an outstanding image; a technique that’s been in use for well over 100 years. But is it possible to use CCDs in place of a mirror or lens entirely? Image credit: Large Area Imager for Calar Alto (LAICA) / J.W. Fried.

Ask Ethan: Why don’t we build a telescope without mirrors or lenses?

Why not just put your detectors in place of a giant mirror?

Ethan Siegel
Oct 7, 2017 · 7 min read

“Look and think before opening the shutter. The heart and mind are the true lens of the camera.” -Yousuf Karsh

For hundreds of years, the principle behind the telescope has been as simple as it gets: build a lens or mirror…