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example 24 then take reading with kamal example 15cm was the length of the string to the board therefore 15cm is equal to 24 degrees. you can keep making different reading the same way for different objects till you have your own standard of measurements. helpful tip make a calibration card and print it on the kamal board it self example 30cm=45degree 20cm=30degree
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card. The kamal is used by placing one end of the string in the teeth while the other end is held away from the body roughly parallel to the ground. The card is then moved along the string, positioned so the lower edge is even with the horizon, and the upper edge is occluding a target star, typically
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it is not necessary to follow a certain standards and calculation to make your own kamal, all you need is piece of wood string and help of a sextant or any angle measuring device for the first calibration of your personal kamal. chose any object preferably
Polaris take the angle reading with sextant
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is currently close to the celestial pole, its elevation is a good approximation of the latitude of the observer. The kamal consists of a rectangular wooden card about 2 by 1 inch (5.1 by 2.5 cm), to which a string with several equally spaced knots is attached through a hole in the middle of the
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Due to the limited width of the card, the kamal was only really useful for measuring
Polaris in equatorial latitudes, where Polaris remains close to the horizon. This fact may explain why it was not common in Europe. For these higher-latitude needs somewhat more complex devices based on the same
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The knots were typically tied to measure angles of one finger-width. When held at arm's length, the width of a finger measures an angle that remains fairly similar from person to person. This was widely used (and still is today) for rough angle measurements, an angle known as
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because its angle to the horizon does not change with longitude or time. The angle can then be measured by counting the number of knots from the teeth to the card, or a particular knot can be tied into the string if travelling to a known latitude.
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Side view of how the kamal was used to measure the elevations of stars. While the lower edge aligns with the horizon, the upper edge indicates the elevation of the star.
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128:指 in Chinese (both meaning 'finger'). By modern measure, this is about 1 degree, 36 minutes, and 25 seconds, or just over 1.5 degrees. It is equal to the
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Cultural
Foundations of Mathematics: The Nature of Mathematical Proof and Transmission of the Calculus From India to Europe in the 16th c. CE
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45:. The invention of the kamal allowed for the earliest known latitude sailing, and was thus the earliest step towards the use of
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155:. In such an application, it can be used for estimating distances to land. The distance can be calculated from the formula
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of the ratio of the width of the finger to the length of the arm. In
Chinese navigation, the unit of
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435:(2003), "The Stellar Compass and the Kamal. An Interpretation of its Practical Use", in
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Portugal's Golden Years, The Life and Times of Prince Henry "The
Navigator"
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439:, Delhi, also published by Academia de Marinha (Lisbon, 2003).
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Usage of the kamal to determine the elevation of the polestar
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is the distance from the kamal to the observer's eye, and
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Celestial navigation device that determines latitude
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151:The kamal is still a tool recommended for use in
57:of the late 9th century, and was employed in the
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375:, Delhi: Pearson Longman, pp. 240–59,
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61:from the 10th century. It was adopted by
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239:is the size of the object observed,
69:some time before the 16th century.
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189:{\displaystyle D={\frac {Sd}{s}}}
140:principle were used, notably the
403:Fundamentals of Kayak Navigation
65:soon after, and then adopted by
219:is the distance to the object,
311:, Hildesheim, Olms, 2019, 398.
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279:is the size of the kamal.
449:Oxford University Press
307:Al Salimi and Staples,
41:device that determines
37:(wood in Arabic), is a
485:Orientation (geometry)
475:Navigational equipment
443:McGrail, Sean (2004),
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33:, often called simply
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25:A simple wooden kamal.
490:Measuring instruments
425:Carreiro, Carlos B.,
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53:. It originated with
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480:Celestial navigation
433:Malhão Pereira, J.M.
366:Raju, C. K. (2007),
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39:celestial navigation
99:Make your own kamal
445:Boats of the World
309:A Maritime Lexicon
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67:Chinese navigators
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382:978-81-317-0871-2
272:{\displaystyle s}
252:{\displaystyle d}
232:{\displaystyle S}
212:{\displaystyle D}
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63:Indian navigators
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118:issabah إصبع
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59:Indian Ocean
47:quantitative
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142:cross-staff
73:Description
49:methods in
469:Categories
420:References
51:navigation
146:backstaff
283:See also
85:Because
43:latitude
35:khashaba
289:Sextant
130:arcsine
92:Polaris
87:Polaris
455:
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199:where
122:Arabic
373:(PDF)
295:Notes
124:or a
31:kamal
453:ISBN
407:ISBN
390:2008
377:ISBN
144:and
134:jiao
126:zhi
120:in
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451:,
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166:D
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