Watercolour painting signed and dated on the back by C. [Christabel] Airy. This painting shows the view from the south window of the Octagon Room, looking over the southern leads of the dwelling house to the South Dome (Altazimuth Dome). The mast of the electrometer, which stood 80 feet high and which was located in the Magnetic Ground, is just visible between the tree and the chimney.

When Flamsteed House was built in 1675-1676, the Octagon Room on the first floor served as the main observing area. Its tall windows allowed for the use of the long telescopes of the day. The dwelling rooms of the Astronomer Royal were on the ground and basement levels below. Between 1835 and 1836, the dwelling rooms were expanded to accommodate George Airy’s growing family. The Altazimuth Dome was built on the walls of the Advanced Building in 1844 to accommodate Airy’s Altazimuth Instrument; this was installed in 1847 and was used primarily for extra-meridian observations of the Moon.