The Sun is the primary source of variations in the space environment through which the Earth moves. In a sense, the Earth is immersed in the Sun's outer atmosphere which consists of the solar wind that is constantly flowing from the Sun. It not only emits large quantities of light and heat, but other electromagnetic radiation such as radio waves, ultraviolet light and X-rays. Huge eruptions occurring on the Sun (Coronal Mass Ejections) can eject large clouds of plasma into space. These, preceded by shock waves may impinge on the Earth's magnetic field and inject plasma particles, creating a geomagnetic storm.

The Learmonth optical telescope monitors solar surface features. These include susnpots, plage, filaments, fibrils, prominences and magnetic fields. These features change constantly and may appear and disappear on time scales from minutes to months. One of the most spectacular events to be viewed on the Sun is a flare, an explosive release of incredible amounts of constrained magnetic energy. The optical telescope, includes many subsystems to monitor all the above phenomena for any potential impact that they might have on, or around, the Earth.