Our Current Our Current Astro-Navigation Astro-Navigation Solutions Solutions Catherine Hohenkerk HM Nautical Almanac Office UK Hydrographic Office
Feb 09, 2016
Our CurrentOur CurrentAstro-Navigation SolutionsAstro-Navigation Solutions
Catherine HohenkerkHM Nautical Almanac Office
UK Hydrographic Office
Astro-NavigationSextant, UT1 & the means of “Sight Reduction”
Almanac The Nautical Almanac
Sight Reduction Tables (SRT) NA’s Concise SRT Marine Navigation : 6 Volumes Rapid SRT Navigation: 3 Volumes–AP3270
Software (or a calculator) NavPac
The Nautical Almanac (NA)
• First published in 1767
Extract: NA right-hand page
Extract: NA left-hand page
•1960, joint pub. with US Naval Observatory
The Nautical Almanac (NP314)• First published in 1767• Current layout developed in the 50s • 1960, joint pub. with US Naval Observatory
• Licensed world wide, via HOs & commercial companies
• An almanac + algorithm for reduction of sights + Concise Sight Reduction Tables
• An NA is a SOLAS requirement
NA Concise Reduction Tables
Altitude (Hc) to 1' and Azimuth (Zn) 1°
Developed in the US (USNO)
NA Concise Reduction Tables
Developed in the US (USNO) Altitude (Hc) and Azimuth (Zn) For use in an emergency Compact — only 32 pages of tables Method accurate to ~2' Complicated to use?
Sight Reduction Tables for
Marine Navigation, NP 401, 6 Volumes Altitude (Hc) to 0'.1 and Azimuth (Zn) to 0º.1 Used with an almanac & compatible with NA Accuracy of method 0'.2 - 0'.3 Joint publication, HMNAO/UKHO, USNO/NGA
UKHO have ceased printing this volume US edition (Pub 229) is still available
Rapid Sight Reduction Tables for Navigation
Air Navigation, AP 3270 / NP 303 3 Volumes Altitude (Hc) to 1' & Azimuth (Zn)
AP3270 / NP 303 : Volume 1 Selected Stars, 2015
Method accurate to 0'.5
AP3270 / NP 303, Volume 2 & 3
Rapid Sight Reduction Tables for Navigation
Air Navigation, AP 3270 / NP 303, 3 Vols Altitude (Hc) & Azimuth (Zn) Volume 1, Selected Stars, “7 best” Volume 2 & 3, require an almanac
Joint publication of HMNAO, USNO (429)
2015 edition of Volume 1, published June
NavPac Software : 1986 - 2015Digital / PCEphemeridesPosition 0'.15NA + AP3270 +
GC/Rhumb sailing + Az for compass checks
CalculationsRN
Recommended
NavPac—RiseSet
Times of:
• Rise & Set
• Twilights
• Meridian Passage
and
•Altitude atMer.pass
NavPac—RiseSet Compass Check
Times when
• Calculated altitude = 0°
• Azimuth
NavPac—Findit
An Astronomical Observation
NavPacSights
NavPac—Sights ResultsCalculations
NavPac—Almanac
NavPac—FinderRhumb Line/Great Circle Routes
Astro-Navigation for the Future
Web availability? Software platform independence? Adobe Acrobat (pdf) e-NA, e-AP3270? Polar navigation? UT1/UTC issues?
What do you think?