WebMarine sextant with a bubble level on the frame, with "Sewill. Maker to the Royal Navy. ... The silvered scale is graduated every 10 minutes from -5° to +155° and read by vernier with tangent screw and swinging magnifier to 10 seconds of arc. A quick-release mechanism at the end of the arm engages with worm teeth cut on the underside of the limb. WebOct 14, 2024 · Degrees are read on the graduated arc, minutes on the vernier scale and seconds on the micrometer drum. Reading a Sextant On and Off the Arc. To the left of zero, your sextant will read from zero to 130 degrees, referred to as "on the arc." However, the measurements also extend a few degrees to the right of zero, referred to as "off the …

The Marine Sextant — Principles, Use, and Buying Guide

WebGraduated arc: graduated edge of the arc. Locking device: apparatus that holds the sextant in place. Drum: graduated button used to take measurements. Index arm: … WebThe arc is graduated with 0 to 140 degrees and a vernier of readings up to 20" is attached to index arm of a sextant. Uses of Nautical Sextant It is used for navigational purposes on ships and boats. It is used for … notepad for windows download

Build a Simple Sextant - NASA

Websextant, instrument for determining the angle between the horizon and a celestial body such as the Sun, the Moon, or a star, used in celestial navigation to determine latitude and … The scales of the octant, sextant, quintant and quadrant are graduated from below zero to 90°, 120°, 140° and 180° respectively. For example, the sextant illustrated has a scale graduated from −10° to 142°, which is basically a quintant: the frame is a sector of a circle subtending an angle of 76° at the pivot of the … See more A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the See more Like the Davis quadrant, the sextant allows celestial objects to be measured relative to the horizon, rather than relative to the instrument. This … See more A sight (or measure) of the angle between the sun, a star, or a planet, and the horizon is done with the 'star telescope' fitted to the sextant using a visible horizon. On a vessel at sea even on See more • Astrolabe • Bris sextant • Davis quadrant • Gago Coutinho • Harold Gatty • History of longitude See more The frame of a sextant is in the shape of a sector which is approximately 1⁄6 of a circle (60°), hence its name (sextāns, sextantis is the Latin word for "one sixth"). Both smaller and … See more Due to the sensitivity of the instrument it is easy to knock the mirrors out of adjustment. For this reason a sextant should be checked frequently for errors and adjusted accordingly. There are four errors that can be adjusted by the navigator, … See more • Her Majesty's Nautical Almanac Office Archived 2011-02-21 at the Wayback Machine • The History of HM Nautical Almanac Office Archived 2016-06-24 at the Wayback Machine • Chapter 17 from the online edition of Nathaniel Bowditch's American Practical … See more notepad for windows free