The Collaborative International Dictionary
Lunar \Lu"nar\ (l[=u]"n[~e]r), a. [L. lunaris, fr. luna the moon. See Luna, and cf. Lunary.]
Of or pertaining to the moon; as, lunar observations.
Resembling the moon; orbed.
--Dryden.Measured by the revolutions of the moon; as, a lunar month.
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Influenced by the moon, as in growth, character, or properties; as, lunar herbs. --Bacon. Lunar caustic (Med. Chem.), silver nitrate prepared to be used as a cautery; -- so named because silver was called luna by the ancient alchemists. Lunar cycle. Same as Metonic cycle. See under Cycle. Lunar distance, the angular distance of the moon from the sun, a star, or a planet, employed for determining longitude by the lunar method. Lunar method, the method of finding a ship's longitude by comparing the local time of taking (by means of a sextant or circle) a given lunar distance, with the Greenwich time corresponding to the same distance as ascertained from a nautical almanac, the difference of these times being the longitude. Lunar month. See Month. Lunar observation, an observation of a lunar distance by means of a sextant or circle, with the altitudes of the bodies, and the time, for the purpose of computing the longitude. Lunar tables.
(Astron.) Tables of the moon's motions, arranged for computing the moon's true place at any time past or future.
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(Navigation) Tables for correcting an observed lunar distance on account of refraction and parallax.
Lunar year, the period of twelve lunar months, or 354 days, 8 hours, 48 minutes, and 34.38 seconds.
Wikipedia
The Moon is Earth's largest natural satellite and the nearest major celestial object. Observing the Moon can be accomplished by using a variety of instruments ranging from the naked eye to large telescopes. For most people, the Moon is the only celestial object upon which surface features can be discerned with the naked eye (some people with good eyesight can see large sunspots on the surface of the Sun using handheld solar filters).
Usage examples of "lunar observation".
I am reasonably confident that we can do so, and with most of the night to spare: the master and I and Dick Richardson all agree very closely in our reckoning, and we should have a very good lunar observation tonight with this clear sky.
His charts all agreed in laying down its latitude as 37 47'S but they differed by well over a degree in longitude: most unhappily his two chronometers had also chosen this moment to disagree, and as the covered skies had not allowed him to make a lunar observation since they met the iceberg he was now obliged to steer for the mean of the recorded longitudes with the help of the mean of the times shown by the chronometers.
His charts all agreed in laying down its latitude as 37047'S but they differed by well over a degree in longitude: most unhappily his two chronometers had also chosen this moment to disagree, and as the covered skies had not allowed him to make a lunar observation since they met the iceberg he was now obliged to steer for the mean of the recorded longitudes with the help of the mean of the times shown by the chronometers.
The only occasions upon which Jack was less than kind were those upon which the young Chileans showed a really grave ignorance of navigation, of determining the ship's course and position by the principles of geometry and nautical astronomy: here he found Daniel and Hanson of the greatest use, and although a lunar observation was harder to understand than a sheet-bend, most of the young men were convinced of the subject's importance, and several learnt to take the sun's altitude at noon.
It is possible by lunar observation to refine the Great Art to a point unattainable in the days when observations were made perforce through the thick and muddled air of Earth.