Definitions in Astronomy and Navigation Made Easy |
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actual adapted altitude passing angle Apparent arrangement Astronomical Astronomical Day Axis azimuth book of reference called Cambridge Captain carefully celestial concave celestial meridian CELESTIAL SPHERE centre CHAPTER CIRCLE CO-ORDINATES circle of altitude circle of declination contains correct declination passing Define definitions in navigation DESCRIPTION diagrams diameter diurnal east point ecliptic elevated equinoctial EXPLANATION figure fixed fully give given the definitions glad Glossary of Navigation Heavenly Body heavens horizon hour circle passing illustrate your definitions intercepted Intersection interval knowledge latitude lines longitude Mean Solar Day mean sun natural Noon OPINIONS-Continued passing through X perpendicular placed plane point of Aries polar distance pole primary great circle prime vertical PRINTED proceed projection reckoning Relations represents right ascension seems Ship for Naval Sidereal south points student SURFACE THREE SYSTEMS tion uniformity valuable west point westward WILLIAM BLACKWOOD young naval officer zenith
Popular passages
Page 14 - A circle is a plane figure contained by one line, which is called the circumference, and is such, that all straight lines drawn from a certain point within the figure to the circumference are equal to one another.
Page 17 - The longitude of a heavenly body is the arc of the ecliptic intercepted between the first point of Aries and the circle of latitude passing...
Page 16 - ... equator intercepted between the first point of Aries and the circle of declination passing through the place of the body in the celestial concave.
Page 19 - Mean Solar Day is the interval between two successive transits of the mean sun over the same meridian ; it begins when the mean sun is on the meridian.
Page 19 - The sidereal day is the interval between two successive transits of the first point of Aries over the same meridian.
Page 17 - Azimuth is the angular distance of a celestial object from the north or south point of the horizon (according as it is the north or south pole which is elevated), when the object is referred to the horizon by a vertical circle ; or it is the angle comprised between two vertical planes — one passing through the elevated pole, the other through the object.
Page 19 - The interval between two successive transits of the actual sun's centre over the same meridian ; it begins when that point is on the meridian. The apparent solar day is variable in length from two causes : first, the sun does not move uniformly in the ecliptic — its apparent path sometimes describing an arc of 57', and at other times an arc of 61...
Page 17 - Owing to the obliquity of the ecliptic — the angle at which the ecliptic is inclined to the celestial equator...
Page 19 - Month. 27-32166 days, the interval between two successive passages of the Moon through the same point in her orbit relative to the fixed stars. Sidereal Noon. The instant when the First Point of Aries is on the meridian at upper CULMINATION (qv), indicated by 0 hours local sidereal time. Sidereal Period. The interval between two successive positions of a celestial body at the same point with reference to the fixed stars; the same applied to an artificial satellite as seen from the Earth, although...