How do Satellites Take Detailed Close-Up Photographs of the Earth?
Perhaps you’ve wondered how reconnaissance satellites take detailed close-up photographs of our home, the Earth. The answer is that they use high-resolution CCD cameras coupled large lenses to take pictures of the ground right below them as they pass over. Pictures taken during poor weather are likely to be filtered out. Even as late as the mid-80s, reconnaissance satellites delivered their pictures back to the Earth using fragile film canisters mounted on parachutes and picked up by planes in mid-air. Today they send back the pictures using encrypted radio transmissions. Most information about modern-day spy satellites is highly classified. So much f our information about how these devices might work is based on guesses and may be speculative. One speculative calculation on the performance of spy satellites uses the Rayleigh criterion, a way of calculating the resolution of an optical image. The equation involves sinθ = 1.22 λ/D, where λ is the wavelength of light, θ is the angula
Perhaps you’ve wondered how reconnaissance satellites take detailed close-up photographs of our home, the Earth. The answer is that they use high-resolution CCD cameras coupled large lenses to take pictures of the ground right below them as they pass over. Pictures taken during poor weather are likely to be filtered out. Even as late as the mid-80s, reconnaissance satellites delivered their pictures back to the Earth using fragile film canisters mounted on parachutes and picked up by planes in mid-air. Today they send back the pictures using encrypted radio transmissions. Most information about modern-day spy satellites is highly classified. So much f our information about how these devices might work is based on guesses and may be speculative. One speculative calculation on the performance of spy satellites uses the Rayleigh criterion, a way of calculating the resolution of an optical image. The equation involves sinθ = 1.22 λ/D, where λ is the wavelength of light, θ is the angular re
