SubscribeMagnetic Variation
Magnetic Variation
In the fin-de-siècle of the sixteenth century mariners believed that the magnetic north pole coincided with the geographic north pole. Any suggestion otherwise had been denied by Pedro de Medina.
Magnetic observations made by explorers in subsequent decades showed however that these suggestions were true. But it took until the early nineteenth century, to pinpoint the magnetic north pole somewhere in Arctic Canada (78° N , 104° W). From then on the angle between the true North and the Magnetic North could be precisely corrected for. This correction angle is called magnetic variation or declination.
It is believed that the Earth's magnetic field is produced by electrical currents that originate in the hot, liquid, outer core of the rotating Earth. The flow of electric currents in this core is continually changing, so the magnetic field produced by those currents also changes. This means that at the surface of the Earth, both the strength and direction of the magnetic field will vary over the years. This gradual change is called the secular variation of the magnetic field. Therefore, variation changes not only with the location of a vessel on the earth but also varies in time.
The correction for magnetic variation for your location is shown on the nearest! nautical chart's compass rose. In this example we find a variation of 4° 15' W in 2009, with an indicated annual correction of 0° 08' E. Hence, in 2011 this variation is estimated to be 3° 59', almost 4° West. This means that if we sail 90° on the chart (the true course), the compass would read 94°.
Another example: let's say the compass rose gives a variation of 2° 50' E in 2007, with a correction of 0° 04' E per year. In 2009 this variation is estimated to be 2° 58', almost 3° East. Now, if we sail 90° on the chart, the compass would read 87°.
Correcting for variation
These overlayed compass roses show the difference between true north and magnetic north when the magnetic variation is 10° West. From the image we find: tc = cc + var
in which “cc” and “tc” stand for “compass course” and “true course”, respectively.
To convert a true course into a compass course we need first assign a “-” to a Western and a “+” to a Eastern variation. Note that this makes sense! because of the clockwise direction of the compass rose. Here, the inner circle is turned 10° anticlockwise, hence -10°
Now, use the same but re-written equation:
cc = tc - var
235° = 225° - (-10°)
So, to sail a true course of 225°, the helmsman has to steer a compass course of 235°.
To convert a compass course into a true course we can use the original equation. If we have steered a compass course of 200°, we have to plot a true course of 203° in the chart if the variation is 3° East
Magnetic deviation
Magnetic deviation is the second correctable error. The deviation error is caused by magnetic forces within your particular boat. Pieces of metal, such as an engine or an anchor, can cause magnetic forces. And also stereo and other electric equipment or wiring, if too close to the compass, introduce errors in compass heading. Furthermore, the deviation changes with the ship's heading, resulting in a deviation table as shown below. The vertical axis states the correction in degrees West or East, where East is again positive.
The horizontal axis states the ship's heading in degrees divided by ten. Thus, when you sail a compass course of 220°, the deviation is 4° W. (Note, that on most modern sailing yachts the deviation is usually not larger than 3°).
When a compass is newly installed it often shows larger deviations than this and needs compensation by carefully placing small magnets around the compass. It is the remaining error that is shown in your deviation table.
You can check your table every now and then by placing your boat in the line of a pair of leading lights and turning her 360 degrees.
Correcting for both deviation and variation
Converting a compass course into a true course, we can still use our equation but we need to add the correction for deviation:
cc + var + dev = tc
- Example 1: The compass course is 330°, the deviation is +3° (table) and the variation is +3° (chart);
330° cc + 3° var + 3° dev = ?° tc
giving a true course of 336° which we can plot in our chart - Example 2: The compass course is 220°, the deviation is -4° (table) and the variation is still +3° (chart).
220° cc + 3° var + -4° dev = ?° tc
giving a true course of 219°. - Example 3: The compass course is still 220°, therefore the deviation is still -4° (table) but let's use a variation of -10° this time.
220° cc + -10° var + -4° dev = ?° tc
giving a true course of 206°.
- Example 4: The true course from the chart is 305° and the variation is +3° (chart), yet we don't know the deviation;
?° cc + 3° var + ?° dev = 305° tc
Luckily, we can rewrite this so this reads:
cc + dev = 305° tc - + 3° var = 302°
In plain English: the difference between the true course and the variation (305 - + 3) = 302 should also be the summation of the compass course and the deviation. So, we can tell our helms person to steer 300°, since with a cc of 300° we have a deviation of +2° (As can be deduced from the deviation table above). - Example 5: The true course from the chart is 150° and we have a Western variation of 7 degrees (-7°). We will use the rewritten equation to get:
150° tc - - 7° var = cc + dev = 157°
From the deviation table we find a compass course of 160° with a deviation of -3°.
Voilà!
Magnetic course
The magnetic course (mc) is the heading after magnetic variation has been considered, but without compensation for magnetic deviation. This means that we are dealing with the rewritten equation from above:tc - var = cc + dev = mc.
Magnetic courses are used for three reasons:
- To convert a true course into a compass course like we saw in the last paragraph.
- On vessels with more than one steering compass, also more deviation tables are in use; hence only a magnetic or true course is plotted in the chart.
- Bearings taken with a handheld compass often don't require a correction for deviation, and are therefore useful to plot in the chart as magnetic courses.
Note, that the actual course lines the navigator draws in the chart are always true courses! These can subsequently be labeled with the true course or the corresponding magnetic or compass course if appropriate. In the next chapter we will be plotting courses in the chart.
To summarise, we have three types of “north” (true, magnetic and compass north) like we have three types of courses: tc, mc and cc. All these are related by deviation and variation.
South Pole
South Pole
From Wikipedia, the free encyclopedia
Coordinates: 90°S 0°W / 90°S 0°W
- This article is about the Geographic South Pole. For other uses see South Pole (disambiguation)
The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where the Earth's axis of rotation intersects the surface. It is the southernmost point on the surface of the Earth and lies on the opposite side of the Earth from the North Pole. Situated on the continent of Antarctica, it is the site of the United States Amundsen-Scott South Pole Station, which was established in 1956 and has been permanently staffed since that year. The Geographic South Pole should not be confused with the South Magnetic Pole.
North Pole
North Pole
From Wikipedia, the free encyclopedia
For other uses, see North Pole (disambiguation).
Coordinates: 90°N 0°W / 90°N 0°W
The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is, subject to the caveats explained below, defined as the point in the northern hemisphere where the Earth's axis of rotation meets the Earth's surface. It should not be confused with the North Magnetic Pole.
The North Pole is the northernmost point on Earth, lying diametrically opposite the South Pole. It defines geodetic latitude 90° North, as well as the direction of True North. At the North Pole all directions point south; all lines of longitude converge there, so its longitude can be defined as any degree value.
While the South Pole lies on a continental land mass, the North Pole is located in the middle of the Arctic Ocean amidst waters that are almost permanently covered with constantly shifting sea ice. This makes it impractical to construct a permanent station at the North Pole (unlike the South Pole). However, the Soviet Union, and later Russia, have constructed a number of manned drifting stations, some of which have passed over or very close to the Pole. In recent years, a number of studies have predicted that the North Pole may become seasonally ice-free due to Arctic shrinkage, with timescales varying from a few years to fifty years or more.
The sea depth at the North Pole has been measured at 4,261 metres (13,980 ft).[1] The nearest land is usually said to be Kaffeklubben Island, off the northern coast of Greenland about 700 km (440 mi) away, though some perhaps non-permanent gravel banks lie slightly further north.
Geographical pole
Geographical pole
From Wikipedia, the free encyclopedia
For other uses, see Pole (disambiguation).
A geographical pole (also geographic pole) is either of the two points—the north pole and the south pole—on the surface of a rotating planet (or other rotating body) where the axis of rotation (or simply "axis") meets the surface of the body. The north geographic pole of a body lies 90 degrees north of the equator, while the south geographic pole lies 90 degrees south of the equator.
It is possible for geographical poles to "wander" slightly relative to the surface of a body due to perturbations in rotation. The Earth's actual physical North Pole and South Pole vary cyclically by a few meters over the span of each few years. This phenomenon is distinct from the precession of the equinoxes of the Earth, in which the angle of the planet (both axis and surface, moving together) varies slowly over tens of thousands of years.
As cartography requires exact and unchanging coordinates, cartographical poles (also cartographic poles) are fixed points on the Earth or another rotating body at the approximate location of the slightly varying geographical poles. These cartographical poles are the points at which the great circles of longitude intersect.
Geographical poles and cartographical poles should not be confused with magnetic poles, which can also exist on a planet or other body.
For the geographical and cartographical poles on Earth, see:
For geographical and cartographical poles on astronomical bodies other than Earth, see Poles of astronomical bodies.
The Equator
The Equator, Hemispheres, Tropic of Cancer, and Tropic of Capricorn
Dateline: 04/16/99Three of the most significant imaginary lines running across the surface of the earth are the equator, the Tropic of Cancer, and the Tropic of Capricorn. While the equator is the longest line of latitude on the earth (the line where the earth is widest in an east-west direction), the tropics are based on the sun's position in relation to the earth at two points of the year.
The Earths axis
The Earths axis is an imaginary line that extends from the physical North pole through the Earth to the physical South pole. Physical poles not magnetic poles. Why the axis is important to us is because the Earth is tilted 23 degrees on this axis in relation to the plane of rotation around the Sun, causing us to experience the different season due to the angle of the suns rays impacting the Earth during the year.
Chart correction
Chart correction
The nature of a waterway depicted by a chart may change, and artificial aids to navigation may be altered at short notice. Therefore, old or uncorrected charts should never be used for navigation. Every producer of nautical charts also provides a system to inform mariners of changes that affect the chart. In the United States, chart corrections and notifications of new editions are provided by various governmental agencies by way of Notice to Mariners, Local Notice to Mariners, Summary of Corrections, and Broadcast Notice to Mariners. Radio broadcasts give advance notice of urgent corrections.
A good way to keep track of corrections is with a Chart and Publication Correction Record Card system. Using this system, the navigator does not immediately update every chart in the portfolio when a new Notice to Mariners arrives, instead creating a card for every chart and noting the correction on this card. When the time comes to use the chart, he pulls the chart and chart's card, and makes the indicated corrections on the chart. This system ensures that every chart is properly corrected prior to use.
Nautical chart
Nautical chart
From Wikipedia, the free encyclopedia
A nautical chart is a graphic representation of a maritime area and adjacent coastal regions. Depending on the scale of the chart, it may show depths of water and heights of land (topographic map), natural features of the seabed, details of the coastline, navigational hazards, locations of natural and man-made aids to navigation, information on tides and currents, local details of the Earth's magnetic field, and man-made structures such as harbours, buildings, and bridges. Nautical charts are essential tools for marine navigation; many countries require vessels, especially commercial ships, to carry them. Nautical charting may take the form of charts printed on paper or computerised electronic navigational charts.
Plane sailing
Plane sailing
From Wikipedia, the free encyclopedia
Plane sailing (also spelled plain sailing) is an approximate method of navigation over small ranges of latitude and longitude.
Both spellings ("plane" and "plain") have been in use for several centuries,[1][2][3]
Plane sailing is based on the assumption that the meridian through the point of departure, the parallel through the destination, and the course line form a right triangle in a plane, called the "plane sailing triangle".
This is the usual method used to navigate using paper charts and maps.
The expression "plane sailing" has, by analogy, taken on a more general meaning of any activity that is relatively straightforward.
Nautical almanac
Nautical almanac
From Wikipedia, the free encyclopedia
This article is about nautical almanacs in general. For other uses including other specific nautical almanacs, see Nautical almanac (disambiguation).
A nautical almanac is a publication describing the positions of a selection of celestial bodies for the purpose of enabling navigators to use celestial navigation to determine the position of their ship while at sea. The Almanac specifies for each whole hour of the year the position on the Earth's surface (in declination and Greenwich hour angle) at which the sun, moon, planets and first point of Aries is directly overhead. The positions of 57 selected stars are specified relative to the first point of Aries.
In Great Britain, The Nautical Almanac has been published annually by the HM Nautical Almanac Office, ever since the first edition was published in 1767. [1] [2] In the United States of America, a nautical almanac has been published annually by the US Naval Observatory since 1852.[2] Since 1958, the USNO and HMNAO have jointly published a unified nautical almanac, for use by the navies of both countries.[2] Almanac data is now available online from the US Naval Observatory.[3] [4]
Also commercial almanacs were produced that combined other information. A good example would be Brown's — which commenced in 1877 - and is still produced annually, its early twentieth century subtitle being "Harbour and Dock Guide and Advertiser and Daily Tide Tables". This combination of trade advertising, and information "by permission... of the Hydrographic Department of the Admiralty" provided a useful compendium of information. More recent editions have kept up with the changes in technology - the 1924 edition for instance had extensive advertisements for coaling stations.
The "Air Almanac" of the United States and Great Britain tabulates celestial coordinates for 10 minute intervals. The Sokkia Corporation's annual "Celestial Observation Handbook and Ephemeris" tabulates daily celestial coordinates (to a tenth of an arcsecond) for the Sun and nine stars.
To find the position of a ship or aircraft by celestial navigation, the navigator uses a sextant to take a 'sight' to measure the apparent height of the object above the horizon, and notes the time from a marine chronometer. The object's position is then looked up in the Nautical Almanac for that particular time and after allowance for refraction, instrument error and other errors, a position circle on the Earth's surface is calculated.
Navigational stars
Navigational stars
From Wikipedia, the free encyclopedia
The navigational stars are used in celestial navigation because they are some of the brightest celestial objects due to their high luminosities and/or their proximity to our solar system. Most of these stars are a subset of the list of brightest stars and are defined by convention and nautical tradition.
No.[3]  | Common name | Magnitude | Bayer designation | SHA | Declination | Distance (ly) | Meaning of name[1] | SIMBAD entry |
|---|---|---|---|---|---|---|---|---|
| 1 | Alpheratz | 2.06 | α And | 358 | N 29° | 97 | the horse's navel | Alpheratz |
| 2 | Ankaa | 2.37 | α Phe | 354 | S 42° | 77 | coined name | Ankaa |
| 3 | Schedar | 2.25 | α Cas | 350 | N 56° | 230 | the breast (of Cassiopeia) | Schedar |
| 4 | Diphda | 2.04 | β Cet | 349 | S 18° | 96 | the second frog (Fomalhaut was once the first) | Deneb Kaitos |
| 5 | Achernar | 0.50 | α Eri | 336 | S 57° | 140 | end of the river (Eridanus) | Achernar |
| 6 | Hamal | 2.00 | α Ari | 328 | N 23° | 66 | full-grown lamb | Hamal |
| * [3] | Polaris | 2.01 var[4] | α UMi | 319 | N 89° | 430 | the pole (star) | Polaris |
| 7 | Acamar | 3.2 | θ Eri | 316 | S 40° | 120 | another form of Achernar | Acamar |
| 8 | Menkar | 2.5 | α Cet | 315 | N 04° | 220 | nose (of the whale) | Menkar |
| 9 | Mirfak | 1.82 | α Per | 309 | N 50° | 590 | elbow of the Pleiades | Mirfak |
| 10 | Aldebaran | 0.85 var[4] | α Tau | 291 | N 16° | 65 | follower (of the Pleiades) | Aldebaran |
| 11 | Rigel | 0.12 | β Ori | 282 | S 08° | 770 | foot (left foot of Orion) | Rigel |
| 12 | Capella | 0.71 | α Aur | 281 | N 46° | 42 | little she-goat | Capella A, Capella B |
| 13 | Bellatrix | 1.64 | γ Ori | 279 | N 06° | 240 | female warrior | Bellatrix |
| 14 | Elnath | 1.68 | β Tau | 279 | N 29° | 130 | one butting with the horns | Elnath |
| 15 | Alnilam | 1.70 | ε Ori | 276 | S 01° | 1300 | string of pearls | Alnilam |
| 16 | Betelgeuse | 0.58 var[4] | α Ori | 271 | N 07° | 430 | the arm pit (of Orion) | Betelgeuse |
| 17 | Canopus | −0.72 | α Car | 264 | S 53° | 310 | city of ancient Egypt | Canopus |
| 18 | Sirius | −1.47 | α CMa | 259 | S 17° | 8.6 | the scorching one (popularly, the dog star) | Sirius |
| 19 | Adhara | 1.51 | ε CMa | 256 | S 29° | 430 | the virgin(s) | Adara |
| 20 | Procyon | 0.34 | α CMi | 245 | N 05° | 11 | before the dog (rising before the dog star, Sirius) | Procyon |
| 21 | Pollux | 1.15 | β Gem | 244 | N 28° | 34 | Zeus' other twin son (Castor, α Gem, is the first twin) | Pollux |
| 22 | Avior | 2.4 | ε1 Car | 234 | S 59° | 630 | coined name | Avior |
| 23 | Suhail | 2.23 | λ Vel | 223 | S 43° | 570 | shortened form of Al Suhail, one Arabic name for Canopus | Lambda Velorum |
| 24 | Miaplacidus | 1.70 | β Car | 222 | S 70° | 110 | quiet or still waters | Miaplacidus |
| 25 | Alphard | 2.00 | α Hya | 218 | S 09° | 180 | solitary star of the serpent | Alphard |
| 26 | Regulus | 1.35 | α Leo | 208 | N 12° | 77 | the prince | Regulus |
| 27 | Dubhe | 1.87 | α1 UMa | 194 | N 62° | 120 | the bear's back | Dubhe |
| 28 | Denebola | 2.14 | β Leo | 183 | N 15° | 36 | tail of the lion | Denebola |
| 29 | Gienah | 2.80 | γ Crv | 176 | S 17° | 165 | right wing of the raven | Gienah |
| 30 | Acrux | 1.40 | α1 Cru | 174 | S 63° | 320 | coined from Bayer name | Acrux A |
| 31 | Gacrux | 1.63 | γ Cru | 172 | S 57° | 88 | coined from Bayer name | Gacrux |
| 32 | Alioth | 1.76 | ε UMa | 167 | N 56° | 81 | another form of Capella | Alioth |
| 33 | Spica | 1.04 | α Vir | 159 | S 11° | 260 | the ear of corn | Spica |
| 34 | Alkaid | 1.85 | η UMa | 153 | N 49° | 100 | leader of the daughters of the bier | Alcaid |
| 35 | Hadar | 0.60 | β Cen | 149 | S 60° | 530 | leg of the centaur | Hadar |
| 36 | Menkent | 2.06 | θ Cen | 149 | S 36° | 61 | shoulder of the centaur | Menkent |
| 37 | Arcturus | −0.04 var[4] | α Boo | 146 | N 19° | 37 | the bear's guard | Arcturus |
| 38 | Rigil Kentaurus | −0.01 | α1 Cen | 140 | S 61° | 4.4 | foot of the centaur | Alpha Centauri |
| 39 | Zubenelgenubi | 3.28 | α Lib | 138 | S 16° | 77 | southern claw (of the scorpion) | Alpha Librae |
| 40 | Kochab | 2.08 | β UMi | 137 | N 74° | 130 | shortened form of "north star" (named when it was that,[5] ca. 1500 BC - AD 300) | Kochab |
| 41 | Alphecca | 2.24 | α1 CrB | 127 | N 27° | 75 | feeble one (in the crown) | Alphecca |
| 42 | Antares | 1.09 | α Sco | 113 | S 26° | 600 | rival of Mars (in color) | Antares |
| 43 | Atria | 1.92 | α TrA | 108 | S 69° | 420 | coined from Bayer name | Atria |
| 44 | Sabik | 2.43 | η Oph | 103 | S 16° | 84.1 | second winner or conqueror | Sabik |
| 45 | Shaula | 1.62 | λ Sco | 097 | S 37° | 700 | cocked-up part of the scorpion's tail | Shaula |
| 46 | Rasalhague | 2.10 | α Oph | 096 | N 13° | 47 | head of the serpent charmer | Rasalhague |
| 47 | Eltanin | 2.23 | γ Dra | 091 | N 51° | 150 | head of the dragon | Eltanin |
| 48 | Kaus Australis | 1.80 | ε Sgr | 084 | S 34° | 140 | southern part of the bow (of Sagittarius) | Kaus Australis |
| 49 | Vega | 0.03 | α Lyr | 081 | N 39° | 25 | the falling eagle or vulture | Vega |
| 50 | Nunki | 2.06 | σ Sgr | 076 | S 26° | 220 | constellation of the holy city (Eridu) | Nunki |
| 51 | Altair | 0.77 | α Aql | 063 | N 09° | 17 | flying eagle or vulture | Altair |
| 52 | Peacock | 1.91 | α Pav | 054 | S 57° | 180 | coined from the English name of Pavo (constellation) | Peacock |
| 53 | Deneb | 1.25 | α Cyg | 050 | N 45° | 3200 | tail of the hen | Deneb |
| 54 | Enif | 2.40 | ε Peg | 034 | N 10° | 670 | nose of the horse | Enif |
| 55 | Al Na'ir | 1.74 | α Gru | 028 | S 47° | 100 | bright one (of the fish's tail) | Al Na'ir |
| 56 | Fomalhaut | 1.16 | α PsA | 016 | S 30° | 25 | mouth of the southern fish | Fomalhaut |
| 57 | Markab | 2.49 | α Peg | 014 | N 15° | 140 | saddle (of Pegasus) | Markab |
[edit] Star charts
Star charts provide an aid to the navigator in locating the navigational stars among the constellations. It is useful to be able to identify stars by relative position - a star chart is helpful in locating these relationships.
Relative bearing
Relative bearing
From Wikipedia, the free encyclopedia
In nautical navigation the relative bearing of an object is the clockwise angle in degrees from the heading of the vessel to a straight line drawn from the observation station on the vessel to the object.
The relative bearing is measured with a pelorus or other optical and electronic aids to navigation such as a periscope, sonar system, and radar systems. Since World War II, relative bearings of such diverse point sources have been and are calibrated carefully to one another. The United States Navy operates a special range off Puerto Rico and another on the west coast to perform such systems integration. Relative bearings then serve as the baseline data for converting relative directional data into true bearings (N-S-E-W, relative to the Earth's true geography). By contrast, Compass bearings have a varying error factor at differing locations about the globe, and are less reliable than the compensated or true bearings.
The measurement of relative bearings of fixed landmarks and other navigation aids is useful for the navigator because this information can be used on the nautical chart together with simple geometrical techniques to aid in determining the position of the vessel and/or its speed, course, etc.
The measurement of relative bearings of other vessels and objects in movement is useful to the navigator in avoiding the danger of collision.
Compass rose
Compass rose
From Wikipedia, the free encyclopedia
For Compass Airlines, an Airline in the US using the Callsign "Compass Rose," See Compass Airlines
A compass rose is a figure on a map or nautical chart used to display the orientation of the cardinal directions, — north, south, east, and west. It is also the term for the graduated markings found on the traditional magnetic compass. Today, the idea of a compass rose is found on, or featured in, almost all navigation systems, including nautical charts, non-directional beacons (NDB), VHF omnidirectional range (VOR) systems, global-positioning systems (GPS), and similar equipment and devices. Early forms of the compass rose were known as wind roses, since no differentiation was made between a cardinal direction and the wind which emanated from that direction. Today, wind roses are used by meteorologists to depict wind frequencies from different directions at a location.
Boxing the compass
From Wikipedia, the free encyclopedia
"Compass point" redirects here. For other uses, see Compass Point.
"ENE" redirects here. For the energy company with the NYSE ticker symbol ENE, see Enron.
 | This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (September 2009) |
Boxing the compass is the action of naming all thirty-two principal points of the compass in clockwise order. Such names, formed by the initials of the cardinal directions and their intermediate ordinal directions, are accepted internationally, even though they have their origin in the English language, and are very handy to refer to a heading (or course or azimuth) in a general or colloquial fashion, without having to resort to computing or recalling degrees.
The set of 32 named points can be further divided into a set of 128 named directions using quarter-points,[1] although for communicating heading these fractional points have been superseded by degrees measured clockwise from North.
Contents[hide] |
[edit] Compass points
A simple algorithm can be used to convert a heading to an approximate compass point:
- Divide the heading in degrees by 11.25 (360/32) to get to the case of 32 named points.
- Add 1.5 to center the named points in their respective sectors on the circle, since north is 1 in the table instead of 0. If the result is 33 or more, subtract 32 to keep within the 32-point set.
- Now look up the integer part of the result in the table below.
For example:
A heading of 75°, divided by 11.25 gives 6.67, added to 1.5 gives 8.17, truncated to give 8. 8 in the table below corresponds to east by north.
| # | Compass point | Abbr. | Traditional wind point | Heading | Heading Range |
|---|---|---|---|---|---|
| 1 | North | N | Tramontana | 0.00° | 0.00 - 5.62° |
| 2 | North by east | NbE | 11.25° | 5.63 - 16.87° | |
| 3 | North-northeast | NNE | 22.50° | 16.88 - 28.12° | |
| 4 | Northeast by north | NEbN | 33.75° | 28.13 - 39.37° | |
| 5 | Northeast | NE | Greco or Bora | 45.00° | 39.38 - 50.62° |
| 6 | Northeast by east | NEbE | 56.25° | 50.63 - 61.87° | |
| 7 | East-northeast | ENE | 67.50° | 61.88 - 73.12° | |
| 8 | East by north | EbN | 78.75° | 73.13 - 84.37° | |
| 9 | East | E | Levante | 90.00° | 84.38 - 95.62° |
| 10 | East by south | EbS | 101.25° | 95.63 - 106.87° | |
| 11 | East-southeast | ESE | 112.50° | 106.88 - 118.12° | |
| 12 | Southeast by east | SEbE | 123.75° | 118.13 - 129.37° | |
| 13 | Southeast | SE | Sirocco | 135.00° | 129.38 - 140.62° |
| 14 | Southeast by south | SEbS | 146.25° | 140.63 - 151.87° | |
| 15 | South-southeast | SSE | 157.50° | 151.88 - 163.12° | |
| 16 | South by east | SbE | 168.75° | 163.13 - 174.37° | |
| 17 | South | S | Ostro | 180.00° | 174.38 - 185.62° |
| 18 | South by west | SbW | 191.25° | 185.63 - 196.87° | |
| 19 | South-southwest | SSW | 202.50° | 196.88 - 208.12° | |
| 20 | Southwest by south | SWbS | 213.75° | 208.13 - 219.37° | |
| 21 | Southwest | SW | Libeccio | 225.00° | 219.38 - 230.62° |
| 22 | Southwest by west | SWbW | 236.25° | 230.63 - 241.87° | |
| 23 | West-southwest | WSW | 247.50° | 241.88 - 253.12° | |
| 24 | West by south | WbS | 258.75° | 253.13 - 264.37° | |
| 25 | West | W | Poniente or Zephyrus | 270.00° | 264.38 - 275.62° |
| 26 | West by north | WbN | 281.25° | 275.63 - 286.87° | |
| 27 | West-northwest | WNW | 292.50° | 286.88 - 298.12° | |
| 28 | Northwest by west | NWbW | 303.75° | 298.13 - 309.37° | |
| 29 | Northwest | NW | Mistral | 315.00° | 309.38 - 320.62° |
| 30 | Northwest by north | NWbN | 326.25° | 320.63 - 331.87° | |
| 31 | North-northwest | NNW | 337.50° | 331.88 - 343.12° | |
| 32 | North by west | NbW | 348.75° | 343.13 - 354.37° | |
| 1 | North | N | Tramontana | 360.00° | 354.38 - 360.00° |
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