- Navigational stars
The navigational stars are used in
celestial navigation because they are some of the brightest celesital objects due to their high luminosities and/or their proximity to oursolar system . Most of thesestar s are a subset of thelist of brightest stars and are defined by convention and nautical tradition.One of the most prominent books on maritime navigation,
Nathaniel Bowditch 'sAmerican Practical Navigator , was the first to list these navigational stars in 1802, and they are still included in the 2002 bicentennial edition of the same book.Nathaniel Bowditch : TheAmerican Practical Navigator , 2002 Bicentennial Ed., Chapter 15 Navigational Astronomy, page 248, Figure 1530a. Navigational stars and the planets] They are commonly listed on a page in thenautical almanac to aid navigators, typically on a tear-sheet that then serves as a bookmark throughout the year and is placed on the almanac page for the current three-day period. [United Kingdom Hydrographic Office : 2008 Nautical Almanace, Commercial Edition, Paradise Cay Publications, ISBN 0-939837-76-5]The coordinates of the stars are typically provided in the
equatorial coordinate system , usingdeclination and sidereal hour angle (SHA). By convention, these stars are numbered and listed from west to east, i.e. by descending SHA. Thenautical almanac lists 57 navigational stars, whereas theAmerican Practical Navigator lists 58, with the inclusion ofPolaris . Thenautical almanac typically providesdeclination only to the nearest full degree in this list, since that is typically sufficient for locating the star with asextant .Navigational stars
Key
Navigational stars
tar charts
Star charts provide an aid to the navigator in locating the navigational stars among the
constellation s. It is useful to be able to identify stars by relative position - astar chart is helpful in locating these relationships.Nathaniel Bowditch : TheAmerican Practical Navigator , 2002 Bicentennial Ed., Chapter 15 Navigational Astronomy, page 249, Section 1532. Star Charts] Star charts are based upon the celestial equator system of coordinates, usingdeclination and sidereal hour angle (orright ascension ).ee also
*
Celestial navigation
*Nautical almanac
*Sextant
*American Practical Navigator
*Star
**Lists of stars
**List of brightest stars
**List of nearest stars
**List of most luminous stars References
;General
*Nathaniel Bowditch : TheAmerican Practical Navigator , 2002 Bicentennial Ed., Chapter 15 Navigational Astronomy
*List of brightest stars ;SpecificExternal links
* [http://aa.usno.navy.mil/data/docs/Nav_Star_Chart.php Navigational Star Chart]
* [http://www.fourmilab.ch/yoursky/catalogues/navstars.html Object Catalogue: Navigation Stars]
* [http://www.angelfire.com/nt/navtrig/F1.html Index of Selected Stars]
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