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Horsemanship

Horsemanship   Reference library

The Oxford Encyclopedia of Medieval Warfare and Military Technology

Reference type:
Subject Reference
Current Version:
2010
Subject:
History, Military History, Social sciences, Warfare and Defence
Length:
1,547 words
Illustration(s):
1

...of horsemanship that was characterized by two basic styles (or “seats”) in medieval mounted warfare, each dependent on the length of the stirrup leather. The styles were discussed in Iberian horsemanship treatises of the fifteenth century, as for example King Duarte I of Portugal, Livro da ensinança de bem cavalgar toda sela (Book of Instruction on Riding Well in All Saddles, 1438 ), but the realities of these styles were present much earlier. The Spanish term a la jineta referred to the style of the Muslims of al-Andalus, who rode with short...

Nautical Astronomy and Celestial Navigation

Nautical Astronomy and Celestial Navigation   Reference library

The Oxford Encyclopedia of Maritime History

Reference type:
Subject Reference
Current Version:
2007
Subject:
History, Military History
Length:
12,412 words
Illustration(s):
6

...Wherever the observer stands, the ground is a plane perpendicular to the observer’s body, a plane that extends outward infinitely. The “poles” of the observer are the zenith, the point on the celestial sphere directly overhead, and the nadir, the point directly below the observer, also in a line perpendicular to the horizon plane. A celestial sphere may feature a number of vertical circles. The great circle intersecting the poles and passing through the observer’s zenith is the principal vertical. Perpendicular to the principal vertical, and passing through east...

Navigational Instruments

Navigational Instruments   Reference library

The Oxford Encyclopedia of Maritime History

Reference type:
Subject Reference
Current Version:
2007
Subject:
History, Military History
Length:
30,532 words
Illustration(s):
5

...that the tangent screw is still simply a slow-motion device with readout by vernier scale. Mirrors were made of optical glass with the two sides ground and polished flat and parallel to avoid parallax errors. Mirrors were mounted in brass housings that could be adjusted to be perpendicular to the frame and parallel to each other. Four shades could be used singly or together to reduce light intensity from the index mirror (three different neutral densities to block sunlight, and a colored moon filter), and three could be used for the horizon glass (two neutral...

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