Tag Archives: calibration targets

The abandoned calibration targets used by surveillance satellites of the 1960s.

The abandoned calibration targets used by surveillance satellites of the 1960s.

“There are dozens of aerial photo calibration targets across the USA,” the Center for Land Use Interpretation reports, “curious land-based two-dimensional optical artifacts used for the development of aerial photography and aircraft. They were made mostly in the 1950s and 1960s, though some apparently later than that, and many are still in use, though their history is obscure.”