Practical Astronomy July – Equatorial Mounts: Why We Use Them and How They Work

Why does a telescope need an equatorial mount, and what makes it different from simpler fixed or altitude–azimuth designs? This beginner-friendly talk starts with the basic problem of following objects across the night sky, then uses practical examples and simulations to explain tracking, field rotation and the deceptively simple idea behind an equatorial mount.

Curator of Instruments, Steve Hennerley, follows the development of telescope mounts from early transit instruments and seventeenth-century helioscopes through to modern computer-controlled equipment. He then moves into the practicalities of setting up an equatorial mount in the Southern Hemisphere, including finding true south, levelling the mount, polar scopes, drift alignment and electronic polar-alignment tools.

No previous knowledge is assumed, making this an accessible introduction for visual observers and anyone beginning to explore astrophotography.