Search results
Results from the WOW.Com Content Network
A nautical mile is a unit of length used in air, marine, and space navigation, and for the definition of territorial waters. [2] [3] [4] Historically, it was defined as the meridian arc length corresponding to one minute ( 1 / 60 of a degree) of latitude at the equator, so that Earth's polar circumference is very near to 21,600 nautical miles (that is 60 minutes × 360 degrees).
A cable in this usage cable is a thick rope or by transference a chain cable. [1] The OED gives quotations from c. 1400 onwards. A cable's length (often "cable length" or just "cable") is simply the standard length in which cables came, which by 1555 had settled to around 100 fathoms (600 ft; 180 m) or 1 ⁄ 10 nautical mile (0.19 km; 0.12 mi). [1]
The nanometre (SI symbol: nm) is a unit of length in the metric system equal to 10 −9 metres ( 1 / 1 000 000 000 m = 0. 000 000 001 m). To help compare different orders of magnitude , this section lists lengths between 10 −9 and 10 −8 m (1 nm and 10 nm).
The length of the internationally agreed nautical mile is 1 852 m. The US adopted the international definition in 1954, having previously used the US nautical mile (1 853.248 m). [6] The UK adopted the international nautical mile definition in 1970, having previously used the UK Admiralty nautical mile (6 080 ft or 1 853.184 m).
The physical group size equivalent to m minutes of arc can be calculated as follows: group size = tan( m / 60 ) × distance. In the example previously given, for 1 minute of arc, and substituting 3,600 inches for 100 yards, 3,600 tan( 1 / 60 ) ≈ 1.047 inches. In metric units 1 MOA at 100 metres ≈ 2.908 centimetres.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Upgrade to a faster, more secure version of a supported browser. It's free and it only takes a few moments:
A circle of 60 NM radius has a circumference of: 2 x 60 x π = 376.99 NM. 376.99 divided by 360° produces: 376.99/360 = 1.047 NM (off by 4.7%) This rule is therefore very good approximation. As a coincidence, 1 NM is about 6,000 feet (6,076.1 feet) so we can use the 60:1 rule for this too.