Altazimuth Pavilion At The Royal Observatory

The Altazimuth Pavilion at the Royal Observatory is a Grade II listed building, constructed around 1899. It is located in the grounds of the New Physical Laboratory, which was built between 1890 and 1899, in a similar architectural style and likely by the same architect, William Crisp, in close collaboration with W H M Christie, the Astronomer Royal.

This pavilion is a one-storey polygonal structure made of red brick in Flemish bond, featuring terracotta decoration and a roof covered with 20th-century synthetic material. The building is open on one side and includes elaborate porches on each side, as well as a central dome topped with a decorative cast iron finial shaped like a sun emblem. The dome also has a coved cornice with oculi for observing stars and planets.

On the northwest side, there are five sash windows with horns, with only the upper parts glazed. The porches are adorned with terracotta moulding that includes triglyphs and paterae, along with elaborate console brackets. Above the terracotta doorcase, there are engaged fluted and rusticated Tuscan columns, an entablature featuring triglyphs, and an eared architrave inscribed with the word "ALTAZIMUTH." The interior features panels and double doors with eight sections, where the top two panels are glazed, and there are three concrete steps leading up to the entrance.

On either side of the porches, there are elaborate octagonal cast iron lamps topped with star finials. The southeast side serves as a garden shelter, featuring five open cambered arches, a ribbed ceiling, and wooden seating, with three steps leading down to the ground. The interior has not been seen. An altazimuth is a structure used for measuring the altitude and azimuth of celestial bodies.