JohnnyM.'s Sextant Geocoin
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Owner:
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JohnnyM.
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Released:
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Sunday, November 22, 2009
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Origin:
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Hlavní město Praha, Czechia
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Recently Spotted:
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In the hands of the owner.
This is collectible.
Use TB35QJF to reference this item.
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To be in small collection of my owner.
I want to travel from event to event with my owner.
You can see me in the hands of JohnnyM. mostly stays in Prague (Czech Republic).
The octant and sextant replaced most of the earlier navigation tools in the late 1700s such as the back staff, mariner's astrolabe, and quadrant. The octant is 1/8 of a circle and a sextant is 1/6 of a circle. The sextant allowed for more range in the degree scale over the octant.
The biggest improvement the sextant made over all other sighting tools (except the octant) is its double reflecting mirrors which eliminated the ocular parallax other tools caused. It also allowed for greater accuracy by having finer degree adjustments.
The sextant design is so universal and accurate that it is still used on ships today as a backup instrument to electrical navigation devices. Even aircraft used these as backups if their avionic systems failed.
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