The History of HM Nautical Almanac Office
The Royal Greenwich Observatory was founded in 1675 by decree of Charles II for
the sole purpose of improving the level of astronomical knowledge required to
support navigation at sea.
The present-day work of HM Nautical Almanac Office continues a 323-year-old
tradition, bringing the latest techniques in astronomy and computation
to the publication of The Nautical Almanac and all of our
other books, software and data services.
1675: The Founding of the Royal Greenwich Observatory
The RGO was founded in 1675 by decree of Charles II. The first Astronomer
Royal, John Flamsteed, was charged
"to apply himself with the most exact care and diligence
to the rectifying of the tables of the motions of the heavens,
and the places of the fixed stars, so as to find out the so much
desired longitude of places for the perfecting the art of navigation."
1767: The Nautical Almanac
Almost a century was to elapse between the founding of the RGO and the first
edition of The Nautical Almanac under the fifth Astronomer Royal,
Nevil Maskelyne. This almanac contained tabulations of the distances of the
Moon's centre from the Sun and from the bright stars for every three hours,
so that the navigator could determine Greenwich time and hence his longitude
from observations of such lunar distances.
1832: The Nautical Almanac Office
The Nautical Almanac Office was established as a separate institution
in 1832 under the auspices of the Admiralty who took
over when the Board of Longitude was abolished. Considerable improvements
in the contents and presentation of the
Almanac were introduced in 1834 by WS Stratford following a survey of the
Astronomical Society who wanted more data
1911: International Cooperation
In 1911, the (then) five principal ephemeris-producing nations (France,
Germany, Great Britain, Spain and the United States) agreed to co-operate in
the production of almanac data, with the aims of avoiding duplication of
effort and of standardising the basis upon which the ephemerides were computed.
This cooperation was further strengthened with the creation, in 1919, of the
International Astronomical Union.
HMNAO and the Nautical Almanac Office of USNO now collaborate closely in every
aspect of the production of The Nautical Almanac, The
Astronomical Almanac and the other publications for which the two Offices
are responsible. The Almanacs are produced in accordance with resolutions of
the International Astronomical Union to meet the needs of astronomers, sailors
and aviators worldwide.
1914: The Nautical Almanac, Abridged for the Use of Seamen
It was recognised late in the 19th century that the Nautical Almanac
contained much information that was of little relevance to the practical
navigator. In 1896, Part I (which contained the navigational data) was
published separately for the first time. In 1914, the separation was made
formal with the introduction of Nautical Almanac, Abridged for the
Use of Seamen which was specially designed for navigation. This almanac
underwent further changes in 1929 and 1952, when it was renamed to the
Abridged Nautical Almanac, and again in 1958. It regained its
original title of Nautical Almanac in 1960.
1937: Re-united with the RGO
In 1937 HMNAO became part of the Royal Greenwich Observatory and the
Astronomer Royal was once again responsible for overseeing the work of the
Office. However, the Office remained separate from the Observatory until it
moved to Herstmonceux in 1949.
1959: Electronic Computing
The computation of the data for the almanacs involved a considerable amount
of effort. As late as the mid-20th century, HMNAO employed a small army of
human computers to carry out this work. They used the latest technology
available at the time: logarithm tables, mechanical calculating machines and
electro-mechanical calculating machines.
In 1959 the Office obtained its own electronic computer, making it the first
part of the RGO to use this emerging technology.
Today, computation of the contents of an edition of The Nautical
Almanac is carried out on a Unix workstation, and much of the layout
work is carried out using TeX on PCs.
1998: The closure of the RGO
With the closure of the RGO, HM Nautical Almanac Office moved to the
Rutherford Appleton Laboratory near Chilton, Didcot in Oxfordshire under the
auspices of the Council for the Central Laboratory of the Research Councils
under the supervision of P.T. Wallace.
2000: The future of HM Nautical Almanac Office
HM Nautical Almanac Office has always been ready to adopt new
technologies, the better to meet the needs of existing customers and to
seek out new users for our products. The rapid growth of the Internet and of
computers in home, schools and the workplace has spurred us to look at new
ways to present our products and services. These web pages are one example;
another is forthcoming The Astronomer's Diary, our first almanac on CD-ROM.
You may also like to see the
list of Superintendents & Heads
list of locations which HM Nautical
Almanac Office has occupied in its 170-year history.
[HMNAO HOME PAGE]
[SUPERINTENDENTS & HEADS]
HM Nautical Almanac Office, Rutherford Appleton Laboratory
Last revision was made on 2001 January 8