Although the Institute was given its present name only in 1972, astronomical research has been carried out on the site since the early nineteenth century. It is among the oldest of the scientific research departments of the University.
The University Observatory is the imposing building at the top of the drive on the East side of the site, nearest to Cambridge. It was completed in 1823 and is now a Listed Building, `especially worthy of preservation', and described by the Historical Monuments Commission as "an example of the use of the revived Greek style [of architecture] for a structure intended for scientific purposes". Extensive work on the external fabric was carried out by the University during 1991-93, largely restoring the building to its original appearance.
Originally it contained telescopes. One was in the central dome, and in the West front were meridian instruments used for the accurate determination of the positions of stars and planets. The slits through which the telescopes were directed can be traced in the external masonry. Their purpose required the main front of the building to run exactly East - West, so the portico faces true South. A small projecting room on the West front housed a collimating telescope for adjusting the main meridian circle; this part of the fabric is exactly to the North of the spire of Grantchester village church, on which originally an oil lamp defined the local meridian.
The Library, at first in the large room to the right of the entrance, is now one of the country's major special collections and has expanded to fill most of the South front of the building, and mobile book stacks in the Michael Penston Rooms, a part of Greenwich House, in which the Royal Greenwich Observatory was located, 1990 - 1998. The Director's house, and the staff house, in the East and West wings, were converted to offices during the 1960s and 70s but still retain many attractive features showing their domestic origin.
To the South-West along the footpath the white dome contains the historic telescope donated by the Duke of Northumberland in the 1830s, which in its time was one of the world's largest refracting telescopes. Situated close by is the smaller Thorrowgood telescope. The grounds about the Observatory still contain many fine trees, including a Wellingtonia in the Director's garden to the East of the main Observatory building. The former Gardener's Cottage (1864) now provides accommodation for visiting astronomers.
The Solar Physics Observatory came to Cambridge in 1912 and was housed in an attractive brick building closer to the Madingley Road. It was originally a Government Observatory and brought to Cambridge a long tradition of observations of the Sun, extended by the operation of an outstation in Malta during 1965-72. Observational studies of the Sun were then discontinued, and the building now contains laboratories and offices. A former staff house provides further office accommodation.
The dome nearest the drive previously contained a 17-inch f/3.7 Schmidt camera . At the West end are the Workshops, and the isolated dome to the South contains the very successful 36-inch reflecting telescope. All these date from the major expansion of the two Observatories in the 1950s. A more recent addition is the Three Mirror Telescope in a small hut to the South of the Schmidt camera.
The Institute of Theoretical Astronomy was created by Fred Hoyle in 1967. It was originally funded by the then Science Research Council, and the single-storey portion of the long building on the West side of the site, approached by a second drive from Madingley Road, was donated by the Wolfson Foundation. The Raymond and Beverly Sackler Lecture Theatre was opened in 1999, and the two-storey Corfield Wing in 2002 to accommodate additional offices and computing facilities. The separate square block nearer the main road at first contained the Institute's own computer, but now provides an admirable housing for the Cambridge Astronomical Survey Unit (CASU).
The present Institute of Astronomy arose from the amalgamation of the above three institutions in 1972.
Radio Astronomy in the University is prosecuted by the Mullard Radio Astronomy Observatory, of the Cavendish Laboratory, and groups in the Department of Applied Mathematics and Theoretical Physics work in areas including relativity, fluid dynamics, and cosmology. With these the Institute works in close cooperation.
Further details of the current research programmes of the Institute of Astronomy are available.