# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Re: The Length of a Day
From: Ron Jones
Date: 2016 May 26, 16:45 -0700

The attached PDF shows the altitude of the Sun as viewed from Ediz Hook (48° 8.5' N 123°  26' W) on May 27 2006.  I use graphs like this which illustrates the length of day light & twilight as viewed from a specified position and date to illustrate to my students how these times varry through the year from a specified position. This graph was produced by my Excel Celestial Navigator Workbook that I use in teaching my USPS JN & N classes. The Celestial Navigator workbook version 12.5 cam be downloaded from:

http://www.uspsd16sg.org/officers_tools/celestial_navigator.xlsm

The Celestial Navigator Workbook contains the following worksheets:

Nav Bodies .. GHA, Dec & other data for Sun, Moon, Planets & Stars for a given date, time & position

Sight Planning .. Help in selecting sights for a two or three body fix

Sight Averaging .. Shows a graph of up to 10 sights and allows bad sights to be removed

Sight Reduction .. Using Law of Cosines Method +NASR +Time Diagram +Meridian Diagram

SR 96 .. Sight Checker for USPS Form SR96

SR by DC .. Sight Reduction by Direct Computation, Nautical Almanac pages 277--> 285

Hs to Ho .. Calculating Ho from Hs, Nautical Almanac pages 280 & 281

Moon Ha to Ho .. Nautical Almanac Moon Altitude Corrections

Meridian Transit .. Latitude by Sight on a body at meridian transit

Polaris .. Latitude by Sight on Polaris, Nautical Almanac pages 274 & 275

24 Hc & Zn .. A graph of the Sun's Altitude and Azimuth vs Zone Time for a given date & position

Analemma .. A graph of the Sun's Declination vs the Equation-of-Time for an entire year

NAV Coordinates .. Celestial Navigation Coordinates & the Celestial Sphere

Yellow Pages .. Nautical Almanac Increments & Corrections

DR 2 Body Fix ..Two Body Fix,  from a DR position

AP 2 Body Fix .. Two Body Fix, from an assumed position

DR 3 Body Fix .. Three Body Fix, from a DR position

AP 3 Body Fix .. Three Body Fix, from an assumed position

Set & Drift .. Calculates set & drift +Track & SMG + Course to Steer & SOA

60 D ST .. Speed, Time & Distance calculations

Interpolation & Data Conversions

Arrival Coordinates .. Calculated using mid-latitude sailing equations

Course & Distance .. Calculated using rhumb line equations

Great Circle Route .. Calculates Great Circle Distance and initial course heading

Rhumb Line .. Distance vs. Great Circle Distance

Tides .. Rule of 1/12 for Tide Prediction

Ron

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