How do telescopes work? How far can they see? Why do people keep putting them on mountains? Why do they cost hundreds of millions of dollars to make? What exactly are they seeing? In this very readable book, physicist Geoff Andersen answers these questions and many more. He describes every aspect of the optical telescope, reveals the exciting developments in space observation today, gives a brief history of the instrument since it was first discovered 400 years ago, and offers useful advice on choosing a telescope for home use.

Everything we know about the universe beyond our Solar System comes entirely from observations made using a telescope of one type or another. We have learnt that while we currently represent a singular example of life, we hold no special place in the universe at large. In fact, it even appears that what we see represents a mere four percent of everything that is ‘out there’. Clearly we have much to learn - and that is where the new generation of telescopes comes in.

But these magnificent instruments do more than simply peer out into space, and Geoff Andersen describes many other applications. Telescopes are being used to project and receive laser beams for communications, lidar and even as weapons. The same instrument can also be used to look down at us from space. These spy satellites have historically been used by secretive government organisations, but are becoming increasingly available to the rest of us. What can they really see?

Eye on the Sky is a superb introduction to a device that is playing an increasingly important part in our lives. It will both inform and surprise you.

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Australian and New Zealand readers can purchase the same text under the title Eye on the Sky, published by Exisle Publishing.