The noon sight

At local apparent noon the Sun crosses your meridian and stands at its highest altitude of the day. Take a run of sights as it climbs, hangs and begins to fall; the greatest is the meridian altitude. Correct it to the observed altitude. The zenith distance is ninety degrees less that altitude; name it north or south, opposite to the Sun's bearing; name the declination north or south from the almanac; combine them: like names add, unlike names subtract, and the result, with the greater's name, is your latitude.

The time of the meridian passage, from the almanac's equation of time and your longitude, tells you when to be on deck; the sight itself needs no time to the second, which is its charm.

The noon sight gives which coordinate?
The zenith distance is what?

Show the answers
  1. The noon sight gives which coordinate? The latitude Only the meridian altitude and the declination enter; longitude would need the time of noon to the second.
  2. The zenith distance is what? Ninety degrees less the observed altitude The zenith is ninety degrees above the horizon; the zenith distance is the body's distance from it.

The twelve evenings

  1. The celestial sphere
  2. The sextant
  3. Time and the almanac
  4. Correcting the altitude
  5. The noon sight
  6. Latitude by Polaris
  7. The navigational stars
  8. The intercept method
  9. Plotting the position line
  10. The running fix
  11. The Moon and the planets
  12. The day's work

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