அறுபாகைமானி
'''அறுபாகைமானி (sextant)''' என்பது கண்ணுக்குப் புலப்படும் இரண்டு பொருட்களுக்கு இடையே [[கோணத்தொலைவு|கோணத்தொலைவை]] அளவிடும் [[இரட்டை எதிரொலிப்பு]] கடற்பயணக் கருவி ஆகும். விண்வெளிப் பயணத்திற்கு தேவையான தொடுவானம் மற்றும் வானியல் பொருட்களுக்கு இடையே உள்ள கோணத்தை அளவிடுவதே அறுபாகைமானியின் முதன்மையான பயன்பாடாகும். [[கிரீன்விச் திட்ட நேரம்]] மற்றும் [[தீர்க்கரேகை]]யை (புவிநெடுங்கோடு) தீர்மானிக்கும் பொருட்டு, நிலவு மற்றும் பிற வானுலக பொருட்களுக்கு ([[நட்சத்திரம்]] அல்லது [[கோள்]] போன்ற) இடையே உள்ள [[நிலவுத் தூரம்|நிலவுத் தூரத்தை]] அளவிட உதவும் கருவி அறுபாகைமானி ஆகும்.&lt;ref&gt;{{cite journal|last=Seddon|first=J. Carl|title=Line of Position from a Horizontal Angle|journal=Journal of Navigation|date=June 1968|volume=21|issue=03|pages=367–369|doi=10.1017/S0373463300024838|url=http://journals.cambridge.org/article_S0373463300024838|issn=1469-7785}}&lt;/ref&gt;
 
 == இவற்றையும் காண்க ==
 * [[நிலநேர்க்கோடு]]
 * [[நிலநிரைக்கோடு]]
 
 == குறிப்புகள் ==
 {{reflist}}
 
 == மேற்கோள்கள் ==
 {{refbegin}}
 *{{cite book
  | first = Nathaniel
  | last = Bowditch
  | authorlink = Nathaniel Bowditch
  | title = The American Practical Navigator
  | publisher = [[National Imagery and Mapping Agency]]
  | url = http://www.irbs.com/bowditch/
  | location = Bethesda, MD
  | year = 2002
  | isbn = 0-939837-54-4
  | access-date = 2017-07-20
  | archivedate = 2007-06-24
  | archiveurl = https://web.archive.org/web/20070624193729/http://www.irbs.com/bowditch/
  }}
 * {{cite book
  | last =Cutler
  | first = Thomas J.
  | title = Dutton's Nautical Navigation
  | edition = 15th
  | date= December 2003
  | publisher = Naval Institute Press
  | location = Annapolis, MD
  | isbn =978-1-55750-248-3
 }}
 *{{cite book
  | author = Department of the Air Force
  | authorlink = United States Air Force
  | title = Air Navigation
  | url = http://static.e-publishing.af.mil/etc/AFPAM11-216.pdf
  | format = PDF
  | accessdate = 2014-12-28
  | date = March 2001
  | publisher = Department of the Air Force
  }}
 *{{cite book
  | author = Great Britain Ministry of Defence (Navy)
  | title = Admiralty Manual of Seamanship
  | publisher = [[The Stationery Office]]
  | year = 1995
  | isbn =  0-11-772696-6 }}
 *{{cite encyclopedia
  | author = Encyclopædia Britannica
  | authorlink = Encyclopædia Britannica
  | editor = Chisholm, Hugh
  | encyclopedia = Encyclopædia Britannica
  | title = Navigation
  | url = https://archive.org/stream/encyclopaediabri19chisrich#page/284/mode/1u
  | accessdate = 2015-01-25
  | edition = 11th
  | year = 1911
  | volume = 19
  | pages = 284–298
  }}
 *{{cite encyclopedia
  | author = Encyclopædia Britannica
  | authorlink = Encyclopædia Britannica
  | editor = Chisholm, Hugh
  | encyclopedia = Encyclopædia Britannica
  | title = Sextant
  | url = https://archive.org/stream/encyclopaediabri24chisrich#page/749/mode/1up
  | accessdate = 2015-01-25
  | edition = 11th
  | year = 1911
  | volume = 24
  | pages = 749–751
  }}
 * {{cite book
  | last =Maloney
  | first = Elbert S.
  | title = Chapman Piloting and Seamanship
  | url =https://archive.org/details/chapmanpilotings00elbe_1
  | edition = 64th
  | date = December 2003
  | publisher = Hearst Communications
  | location = New York
  | isbn =1-58816-089-0
 }}
 {{refend}}
 
 == வெளி இணைப்புகள் ==
 {{Wiktionary}}
 {{Commons|Sextant}}
 * [http://www.hmnao.com/ Her Majesty's Nautical Almanac Office] {{Webarchive|url=https://web.archive.org/web/20110221154351/http://www.hmnao.com/ |date=2011-02-21 }}
 * [http://astro.ukho.gov.uk/nao/history/ The History of HM Nautical Almanac Office] {{Webarchive|url=https://web.archive.org/web/20160624072559/http://astro.ukho.gov.uk/nao/history/ |date=2016-06-24 }}
 * [http://en.wikisource.org/wiki/The_American_Practical_Navigator/Chapter_17 Chapter 17 from the online edition of [[Nathaniel Bowditch]]'s ''American Practical Navigator'']
 * [http://www.erakart.com/nauticals/12-brass-sextant/ Understand difference in Antique &amp; Replica Sextant] {{Webarchive|url=https://web.archive.org/web/20170817004008/http://www.erakart.com/nauticals/12-brass-sextant/ |date=2017-08-17 }}
 * [http://www.tecepe.com.br/nav/CDSextantProject.htm CD-Sextant – Build your own sextant] Simple do-it-yourself project.
 * [http://www.historicalatlas.com/lunars Lunars web site. online calculation]
 * [http://www.celnav.de/ Complete celnav theory book, including Lunars]