The Altazimuth Pavilion was completed in 1896, having been designed by William Christie and William Crisp. It's design was in keeping with that of the New Physical Observatory, which was in the process of being built. It is named after the altazimuth telescope that it was built to house, an instrument designed to measure both altitude (position above the horizon) and the azimuth (position east along the horizon) of celestial objects. It was also known as the Universal Transit Circle and replaced the earlier altazimuth designed by George Biddell Airy. Christie's instrument no longer survives and the dome now contains a photoheliograph, a telescope used to photograph the sun.