14 Plate Set with Key These photographs from the Harvard College Observatory plate stacks, the Lick Observatory Sky Survey, and the Palomar Sky Survey (1950) are high-quality reproductions of regions of the sky with stars, nebulae, and galaxies. A complete key is included for identification. Activities include the effect of the focal length of a telescope on image size, and estimating the distances to two galaxies by comparing images taken by the same telescope and the identification of deep sky objects.

One set could be ordered for each student to accompany the activity book, Where We Are in Space and Time, or a few sets could be ordered by the teacher for use in the classroom.