The RGO archives collection is now deposited in the University Library and consists of all the surviving historical paper records of the Royal Observatory from 1675 until circa 1980, though many later records are held and the collection accrues as material is deposited. The records are public records under the 1958 Public Records Act and are subject to the provisions of the 1958 and 1967 Acts, including the 'thirty-year rule'; at present all records created before 1992 January 01 are open for inspection. The records are also covered by the 2000 Freedom of Information Act and the 2018 Data Protection Act. The Royal Observatory papers are read in the Manuscripts Reading Room in the University Library.

For more than two centuries the Royal Observatory functioned on an established staff of ten or fewer and the official record of the Observatory's work is contained in the papers of the Astronomers Royal. It is these papers which constitute the first classes of the collection:

RGO 1 Papers of John Flamsteed, Astronomer Royal 1675-1719
RGO 2 Papers of Edmond Halley, Astronomer Royal 1720-1742
RGO 3 Papers of James Bradley, Astronomer Royal 1742-1762 and Papers of Nathaniel Bliss, Astronomer Royal 1762-1764
RGO 4 Papers of Nevil Maskelyne, Astronomer Royal 1765-1811
RGO 5 Papers of John Pond, Astronomer Royal 1811-1835
RGO 6 Papers of George Airy, Astronomer Royal 1835-1881
RGO 7 Papers of William Christie, Astronomer Royal 1881-1910

It should be noted that there are classes of RGO Archives which contain significant amounts of eighteenth and nineteenth century papers that do not fall under the classes of Astronomers Royal papers. In the context of the Royal Observatory's work these importantly include:

RGO 14 Papers of the Board of Longitude 1737-1828
RGO 15 Papers of the Royal Observatory, Cape of Good Hope 1820-1978

Two influences expanded the role of the Royal Observatory towards the end of the nineteenth century. Historically the Observatory's founding warrants, and all those succeeding, directed that the work of the Observatory should be to perfect astronomical navigation and up until the end of Airy's tenure it was essentially observational work towards this end which was carried out at Greenwich. However during Christie's period in office much more powerful instruments were installed at Greenwich, reflecting the Astronomer Royal's interest in physical astronomy. The greater number of instruments of higher power required a larger staff.

At the same time the organisation of the Observatory became more structured, affected by the greater influence of wider civil service procedures, and this departmentalisation also led to a higher number of staff. In terms of the archival record, this has resulted in a greater fragmentation leading to a higher number of the classes, the papers of the Astronomers Royal no longer embodying the entire record of the work of the Observatory.

This should be borne in mind when reading the twentieth century papers of the Royal Observatory. The Astronomers Royal during this period were:

RGO 8 Frank Watson Dyson, Astronomer Royal 1910-1933
RGO 9 Harold Spencer Jones, Astronomer Royal 1933-1955
RGO 10 Richard van der Reit Woolley, Astronomer Royal 1956-1971

Before Woolley's retirement in 1971 it was announced that the title of Astronomer Royal would not in future necessarily be awarded to the current Director of the Royal Greenwich Observatory, and, in fact, no Astronomer Royal after 1971 was also concurrently Director. Nonetheless, the classes of the papers of the Directors of the Royal Greenwich Observatory (this title for the Observatory only came into use in 1948 after the move of the Observatory from Greenwich to Herstmonceux in Sussex had begun) are significant:

RGO 11 Papers of Eleanor Margaret Burbidge, Director 1972-1973
RGO 12 Papers of Alan Hunter, Director 1973-1975
RGO 13 Papers of Francis Graham Smith, Director 1976-1981
RGO 176 Papers of Alexander Boksenberg, Director 1981-1995
RGO 203 Papers of Jasper Vivian Wall, Director 1995-1998
Readers should note, however, that the thirty year rule currently applies to the last three of the above classes and that these papers are not available for inspection.

With the increase in the importance of the departmental structure already referred to, so the departments created their own records, the head of the department frequently imposing his personal stamp to such an extent that they also reflect the professional papers of that individual.

RGO 16 HM Nautical Almanac Office papers (including Donald Sadler papers)
RGO 43 Time Department papers (including Humphry Smith papers)
RGO 53 RGO Meridian Department papers
RGO 64 RGO Solar Department papers
RGO 71 Chronometer Department papers
RGO 91 RGO Engineering Department papers
RGO 92 RGO Instrumentation Science Department papers
As the above are twentieth century records, please note that the thirty-year rule will apply to all or parts of these classes, and that modern records of this sort will not be available for inspection.

Other important classes are those containing the official sets of Royal Observatory and HM Nautical Almanac Office publications and some publications of the Cape Observatory, the most important amongst which are:

RGO 17 Royal Observatory reports of the Astronomers Royal, etc.1836-1998
RGO 20 Royal Observatory Annals
RGO 21 Royal Observatory Bulletins
RGO 28 Nautical Almanac 1767-1959
RGO 29 Astronomical Ephemeris 1960-1980
RGO 30 Star Almanac for Land Surveyors 1951-present
RGO 31 Air Almanac 1937-present
RGO 52 Astronomical Almanac 1981-present
RGO 104 Nautical Almanac part 1 and Abridged Nautical Almanac 1896-1959
RGO 180 Nautical Almanac 1960-present
RGO 182 Astronomical Phenomena 1981-present
Published material is not, of course, subject to the thirty-year rule. Over the years significant deposits of the private papers of astronomers, some of whom have never been members of staff of the RGO, have been received, notably:

RGO 37 Papers of Roderick Oliver Redman (1905-1975)
RGO 45 Papers of John Guy Porter (1900-1981)
RGO 46 Papers of Leslie John Comrie (1893-1950)
RGO 54 Papers of William Ellis (1828-1916)
RGO 59 Papers of George Lyon Tupman (1838-1922)
RGO 60 Papers of Francis Baily (1774-1844)
RGO 69 Papers of Richard Sheepshanks (1794-1855)
RGO 73 Papers of Warren de la Rue (1815-1889)
RGO 74 Papers of Philbert Jacques Melotte (1880-1961)
RGO 75 Papers of John Franklin Adams (1843-1912)
RGO 77 Papers of Robert d'Escourt Atkinson (1898-1992)
RGO 206 David Kinnebrook correspondence (ca. 1773-1802)

Readers should note that due to the personal nature of such papers parts or all of the material within the individual classes above may not be open to inspection. Where the person is still living, the class may be accruing and cataloguing will not be complete. It should not be inferred that the assignment of a class number and title necessarily indicates that there is a comprehensive collection of personal papers in the class.

Important papers from other observatories (in addition to the RGO 15 Cape papers, above) have accrued to the RGO collection over time, as have both internal and external telescope construction, management and observational papers:

RGO 44 Isaac Newton Telescope papers
RGO 47 Anglo-Australian Telescope papers
RGO 48 Radcliffe Observatory papers
RGO 49 Northern Hemisphere Observatory papers
RGO 66 Kew Observatory papers
RGO 87 RGO Danjon Astrolabe papers
RGO 93 Satellite Laser Ranger project papers
RGO 100 RGO Roque de Los Muchachos Observatory papers
RGO 103 RGO Photographic Zenith Tube records
RGO 106 William Herschel Telescope records
Prospective readers should note that several of the above classes are accruing papers and are as yet not catalogued.

The Royal Greenwich Observatory archives collection is rich in all manner of related papers. As the Archive is still in the process of being catalogued a full listing of the holdings is not as yet available on the site. However, a full list of RGO classes is available from staff in the Department of Manuscripts Reading Room. Please note that all the observational records of the RGO not created on paper, such as those in the form of glass photographic plates and those created on machine readable media are not held in the University Library.

On its closure in 1998, large series of modern records were taken into the collection in the University Library as potential public records for retention, and further accruals of modern records will continue for some years. The collection will, as it has historically, continue to receive deposits of relevant personal papers.