Abbreviation | General Nautical Terminology | Light Characteristic | Nautical Topics | Navigation | Signals & Communication
Nautical Chart Light Characteristic
A compact description of a light.
Navigation
Marine navigation has its own secret language, and let’s face it—half of it sounds like someone making things up after too much grog. You’ve got your ‘dead reckoning,’ which isn’t nearly as ominous as it sounds, and ‘bearing,’ which has nothing to do with polar bears but everything to do with pointing the right way. Don’t even get us started on ‘knots’—why measure speed like you’re tying a shoelace? And then there’s ‘fix (not for your engine) and ‘DR’ (spoiler: it’s not a doctor). If you’re baffled, don’t worry—we’re here to help you decipher this nautical code so you can sound like a pro, not a landlubber who’s lost their compass.
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Abbreviation | General Nautical Terminology | Light Characteristic | Nautical Topics | Navigation | Signals & Communication
Group Light Characteristic
Uses numbers in brackets to show how many flashes or eclipses form each repeating group.
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Abbreviation | General Nautical Terminology | Light Characteristic | Nautical Topics | Navigation | Signals & Communication
Charted Light Colours
The standard colour codes are W for white, R for red, G for green, Bu for blue, Vi for violet, Y for yellow, Am for amber and Or for orange.
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Abbreviation | General Nautical Terminology | Light Characteristic | Nautical Topics | Navigation | Signals & Communication
Obscured Light Sector (Obscd)
An arc in which the light is not visible or is intentionally screened.
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Abbreviation | General Nautical Terminology | Light Characteristic | Nautical Topics | Navigation | Signals & Communication
Intensified Light Sector (Intens)
An arc in which the light is shown with greater luminous intensity than in adjacent sectors.
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Abbreviation | General Nautical Terminology | Light Characteristic | Nautical Topics | Navigation | Signals & Communication
Unintensified Light Sector (Unintens)
An arc in which the light has less intensity than its intensified sector.
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Position Approximate (PA)
The position of the charted feature is not accurately determined.
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Wind Triangle
A vector diagram combining a craft’s motion through the air with wind to determine its motion over the ground, or the reverse. The three vectors must use consistent direction, units, scale and time. In marine work an analogous construction combines boat speed through the water with tidal stream.
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User Equivalent Range Error
A combined estimate of the ranging errors affecting a satellite-navigation measurement, expressed as an equivalent distance. It includes satellite clock and orbit error, atmospheric delay, receiver noise and multipath components as applicable. Position error also depends on satellite geometry, so UERE is not itself the final position uncertainty.
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UT1
A time scale based on the Earth’s actual angle of rotation relative to astronomical reference directions. Because Earth’s rotation is irregular, UT1 gradually differs from uniform atomic time. UTC is kept close to UT1 through internationally managed adjustments, and the difference is important in precise astronomy and geodesy.
If you belive the Earth is flat, you're about to fall of the end...
If you belive the Earth is flat, you're about to fall of the end...
