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Orders over 75 will be dispatched FREE OF CHARGE to any address within the UK & Ireland.

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NavPac and Compact Data 2021 - 2025

REF: DP330-20


(Ex VAT)

Stock CodeDP330-20
PublisherUK Hydrographic Office
AuthorHer Majesty's Nautical Almanac Office

NavPac  and  Compact Data  is produced by HM  Nautical Almanac Office to provide navigators and astronomers with  simple  and  efficient methods for calculating the  positions of the  Sun,  Moon, navigational  planets and stars  to a  consistent precision  with the aid of a personal computer

running  the  Microsoft Windows  operating system (versions  8  &  I   0).

NavPac  enables  navigators to compute their  position  at sea.  Its  manual is  included  on the  CD-ROM and includes  part of the  Royal  Navy's guide  issued  to those  taking  the  Navigation Watch  certificate. The  package  contains features additional to the  book,  e.g.  planning  sights and calculating great circle  and  rhumb-line  tracks. There are also  functions for determining rise/set and twilight times, calculating altitudes and azimuths and assisting  with gyrocompass checks.

NavPac  is used  world-wide  by the  Royal  Navy,  other  navies, and by many navigators who require an  independent  means  of navigation and a  backup to GNSS. The tables of coefficients and the algorithm  for  determining position at sea from  observations made  with  a marine sextant has been used  by navigators since   1981.

Additional astronomical data  files are stored  on the CD-ROM  which  can  be read  into  any personal computer. Astronomers,  navigators,  surveyors and general users  will find  these  data files  ideal for  making  astronomical calculations where  positions of the  Sun,  Moon,  navigational planets and stars are required.

Further information  about  NavPac  and Compact Data,  including  registration and  user guides, is available at

Issued  by Her  Majesty's  Nautical Almanac Office

Orders placed with us will be dispatched within one to two working days. Dispatch is dependant upon the time when the order is received and provided that all goods ordered are immediately available. If any items are temporarily out of stock, we will endeavour to dispatch the complete order within 7 working days. We only ship complete orders and do not, as a general rule, ship part orders.

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