| Home | Sections | Shop CA House | Join the CA | Contact us |
|
| ||||
|
| ||||
Library > New Acquisitions > Book Review
NavPac and Compact Data, 2006 - 2010; C Y Hohenkerk and B D Yallop; 6th ed., 2005; HM’s Almanac Office; £60; CA 16627
It provides navigators and astronomers with simple and efficient methods of calculating the positions of the Sun, Moon and navigational planets and stars to a consistent precision with the aid of a Windows based PC or programmable calculator for the period 1st January 1986 to 31st December 2010. This edition specifically covers new data for the period from 1st January 2006 to 31st December 2010. Prior editions have covered the preceding periods in 5 year increments.
The NavPac software package (version 2.1.2) comes on a CD-Rom. It includes an electronic version of the manual, part of the official Royal Navy’s guide for those taking the Navigation Watch Certificate using NavPac. NavPac is also the accepted standard for commercial shipping watch officers. The underlying methodology is based on the recommendations of IAU 2000 with an improved refraction algorithm. The changes in this new version are detailed in the manual. The system gives a positional accuracy for the Sun, planets and stars of around 2”. For the Moon the accuracy is usually better than 0’·2. NavPac thus has a more accurate almanac than many yachting astronomical programs which use undocumented perpetual almanacs.
NavPac was originally written in 1992 for DOS and as such its user interface looks somewhat dated in style, though the latest version will now work under Windows 95 and all later versions of Windows.
The book is mainly of interest to those concerned with the implementation of accurate almanac algorithms or to those who wish to extend previous almanac predictions up to the end of 2010, since it contains a number of worked test examples. - DH
Page prepared 22 February 2006