From Wikipedia, the free encyclopedia The Nautical Almanac
The Nautical Almanac
The Nautical Almanac has been the familiar name for a 1907-1919, examples of how to calculate them were given
series of official British almanacs published under vari- instead.[9]
ous titles since the first issue of The Nautical Almanac and Time: The issues for 1767 to 1833 gave their
Astronomical Ephemeris, for 1767: this was the first nauti- ephemeris tabulations in terms of Greenwich apparent
cal almanac ever to contain data dedicated to the con- (not mean) time. This was on the grounds that an impor-
venient determination of longitude at sea. It was origi- tant class of user was the ’Mariner’, and that ’apparent
nally published from the Royal Greenwich Observatory in Time’ was ’the same which he will obtain by the Altitudes
England.[1][2][3] A detailed account of how the publication of the Sun or Stars in the Manner hereafter prescribed’.
was produced in its earliest years has been published by Mean time at Greenwich (i.e. mean solar time) was adopt-
the National Maritime Museum.[4] ed as from the issue for 1834 and continued to 1959.[10]
Since 1958 (with the issue for the year 1960), Her Until the issue for 1924, the time argument for Green-
Majesty’s Nautical Almanac Office and the US Naval Ob- wich Mean Time was counted from 0h starting at Green-
servatory have jointly published a unified Nautical Al- wich mean noon (on the civil day with the same number),
manac, for use by the navies of both countries.[5] and starting with the issue for 1925 the commencement
point of the time argument was changed so that 0h be-
Publication history came midnight at the beginning of the civil day with the
relevant number), to coincide for the future with the civ-
The changing names and contents of related titles in the il reckoning.
series are summarised as follows. (The issue years men- During parts of the period 1767-1959, separate sub-
tioned below are those for which the data in the relevant sidiary titles dedicated to navigation were also published:
issue were calculated—and the issues were in practice • For 1896-1913: Part 1 of the "Nautical Almanac and
published in advance of the year for which they were cal- Astronomical Ephemeris" (containing the astro-
culated, at different periods of history, anything from 1 navigational data) was also published separately as
to 5 years in advance). "The Nautical Almanac & Astronomical Ephemeris,
(For many years, official nautical almanacs and astro- Part 1".
nomical ephemerides in the UK and the USA had a linked • For 1914-1951: the former Part 1 (after redesign) was
history, and they became merged in both titles and con- renamed "The Nautical Almanac Abridged for the
tents in 1981.)[3] Use of Seamen".
In the UK, the official publications have been:[2][6] • For 1952-1959: after further redesign, it was again
renamed, as "The Abridged Nautical Almanac" (and
1767-1959 renamed yet again for 1960 onwards as simply "The
Nautical Almanac").
• For 1767-1959, "The Nautical Almanac and
Astronomical Ephemeris" contained both astro-
navigational and general astronomical data (this 1960-1980
complete publication was often referred to, for • From the issues for 1960, the official titles were
short, especially in the earlier years, as just "The redesigned and unified (as to content) between the
Nautical Almanac"). From 1832, responsibility for UK and USA, under the titles (in UK) "The
publication was transferred to Her Majesty’s Nautical Astronomical Ephemeris" and (separately) "The
Almanac Office. Nautical Almanac".
The main distinctive feature of the inaugural issue for Time: A major change introduced with the 1960 issue of
1767 was the tabulation of lunar distances as a tool to fa- "The Astronomical Ephemeris" was the use of ephemeris
cilitate the determination of longitude at sea from obser- time in place of mean solar time for the major ephemeris
vations of the Moon.[7] Within a few years, the publishers tabulations.[11] But the Nautical Almanac, now continu-
of almanacs of other countries began to adopt the prac- ing as a separate publication addressed largely to naviga-
tice of tabulating lunar distances.[8] Lunar distances con- tors, continued to give tabulations based on mean solar
tinued to be published in the UK official almanacs un- time (UT).
til 1906, by which time their use had declined in prac-
tice. For some time thereafter, in the issues for the years
1
From Wikipedia, the free encyclopedia The Nautical Almanac
1981 to date astronomical-applications/publications/hist-naut-
almanac. Retrieved 11 October 2010.
• For 1981 to date, the official titles have been unified [6] ESAE 1961, see esp. sect.1B.
in UK and USA (as to title as well as (redesigned) [7] D Howse, ’Nevil Maskelyne - The Seaman’s
content): "The Astronomical Almanac" and "The Astronomer’, Cambridge, 1989, esp. at p.87; also, on
Nautical Almanac".[3] p.90, Howse points out that the idea of an almanac
with lunar distances had previously been proposed
The British Nautical Almanac in France, by Lacaille, e.g. in a paper annexed to
the French almanac ’Connaissance des Temps’ for
in the USA 1761 (published 1759). Lacaille had provided a
sample table of pre-computed lunar distances for
In the USA, an official (and initially separate) series of
fourteen days of July 1761, tabulated at 4-hour
ephemeris publications began with the issue for 1855 as
intervals, and promised more to come, but the
"The American Ephemeris and Nautical Almanac"; but
proposal was not further implemented there.
before that, the British "Nautical Almanac" was common-
[8] Guy Boistel, ’Astronomie Nautique au XVIIIeme
ly used on American ships and in the United States[12]
siecle en France’ (2001), vol.1, p.264, showing for
-- sometimes in the form of an independently printed
example that Lalande in Paris incorporated lunar
American ’impression’ instead.[13]
distances into the long-established ’Connaissance
des Temps’ as from the issue for 1774 (published
Modern alternative data 1772) -- initially as a copy of the English lunar-
distance data, and still based on the Greenwich
sources meridian as in the Nautical Almanac itself, moving
Almanac data is now also available online from the US later to lunar-distance data independently
Naval Observatory.[14] calculated for the meridian of Paris.
[9] ESAE 1961, sect. 7D, p.190.
[10] ESAE 1961 at pp.3-5, sect.1B.
See also [11] ESAA 1992, p.612.
• American Ephemeris and Nautical Almanac (specific [12] ESAE (1961), sect.1B
title) [13] G W Blunt White Library at the Mystic Seaport
• Astronomical Almanac (specific title) Museum, Mystic, Connecticut, CT 06355, USA, for a
• Astronomical Ephemeris (generic article) copy of an independent ’Second American
• Almanac (generic article) impression’ of (the British title) "The Nautical
• Nautical almanac (generic article) Almanac and Astronomical Ephemeris" for 1804,
e.g. at https://library.mysticseaport.org/initiative/
References ImPage.cfm?PageNum=1&BibId=21382&ChapterId=1
(retrieved Feb 19, 2009)
[1] "The History of HM Nautical Almanac Office". HM [14] "Celestial Navigation Data for Assumed Position
Nautical Almanac Office. Archived from the and Time". US Naval Observatory.
original on 30 June 2007. http://web.archive.org/ http://www.usno.navy.mil/USNO/astronomical-
web/20070630074456/http://www.nao.rl.ac.uk/ applications/data-services/cel-nav-data. Retrieved
nao/history/. Retrieved 31 July 2007. 11 October 2010.
[2] ^ ’ESAE 1961’: ’Explanatory Supplement to the
Astronomical Ephemeris and the American
Ephemeris and Nautical Almanac’ (’prepared
Bibliography
jointly by the Nautical Almanac Offices of the • Mary Croarken (2002), "Providing Longitude for All",
United Kingdom and the United States of America’, Journal of Maritime Research (National Maritime Museum,
HMSO, London, 1961) Greenwich), September 2002.
[3] ^ ’ESAA 1992’: ed. P K Seidelmann, ’Explanatory
Supplement to the Astronomical Almanac’ (CA,
1992).
External links
[4] M Croarken (2002), "Providing Longitude for All". • HM Nautical Almanac Office: Publications
[5] "History of the Nautical Almanac". US Naval • Online catalogue to copies of the Nautical Almanac
Observatory. http://www.usno.navy.mil/USNO/ held as part part of the Royal Greenwich Observatory
Archives at Cambridge University Library
Retrieved from "http://en.wikipedia.org/w/index.php?title=The_Nautical_Almanac&oldid=418364000"
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From Wikipedia, the free encyclopedia The Nautical Almanac
Categories:
• Almanacs
• Astrometry
• 1767 establishments in Great Britain
• British non-fiction books
• Maritime books
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