Describes how nebulae or clouds of dust particles and gases in space form from the residue of dying stars and how some nebulae contain matter from which stars are born.
Discusses the basic principles of relativity and uses "thought experiments" to explain concepts such as the relationship between space and time, gravitation and acceleration, and the curvature of space.
Gives instructions for building or making theodolites, sundials, telescopes, spectroscopes, planetariums, and models of stars, and describes methods and times for observing the sun, moon, planets, stars, comets, and meteors.
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