Nautical Publication Number: NP 321
This almanac contains positions of the Sun, Polaris and selected bright stars in a form which is convenient for land surveyors who use astronomical observations to determine their geographical position or direction to true north. This edition includes a CD-RoM which contains the almanac in pdf format and the coefficients representing the positions of the Sun and stars in ASCII files.
ASCII data files are available on the CD-RoM which contain coefficients for calculating the Greenwich hour angle and declination of all the stars published in The Star Almanac, accurate to about 1 arcsecond. The polynomial coefficients for calculating R (GHA Aries - UT), declination, E and semi-diameter of the Sun published on page 75 of the Almanac are also included.
Starting with the 2011 edition, this publication is now printed on A5 paper.
To buy HMNAO Astronomical Publications including The Star Almanac for Land Surveyors please select from the links below:
Preferred UKHO Distributors: Thomas Gunn Online Shop
You can also order your copy from Admiralty Paper Distributors.
Other Outlets: TBA
UKHO Nautical Publication number: NP 321-13
Published in the UK: 2012 May 24th
13 character ISBN: 978-0-7077-41383
Retail price: £18.25
UKHO Nautical Publication number: NP 321-14
Published in the UK: 2013 May/June
13 character ISBN: TBA
Retail price: £ TBA