The assembly meetings did not occur at fixed intervals, as they had to avoid clashing with the annual festivals that followed the lunar calendar.

The Thai zodiac includes a Naga in place of the Dragon and begins, not at Chinese New Year, but at either on the first day of fifth month in Thai lunar calendar, or during the Songkran festival ( now celebrated every 13 – 15 April ), depending on the purpose of the use.

Early evidence of such practices appears as markings on bones and cave walls, which show that lunar cycles were being noted as early as 25, 000 years ago ; the first step towards recording the Moon ’ s influence upon tides and rivers, and towards organizing a communal calendar.

* A " luni-solar calendar " is based on a combination of both solar and lunar reckonings ; examples are the traditional calendar of China, the Hindu Calendar in India or the Hebrew calendar.

A lunar calendar is one in which days are numbered within each lunar phase cycle.

Because the length of the lunar month is not an even fraction of the length of the tropical year, a purely lunar calendar quickly drifts against the seasons, which don't vary much near the equator.

Alexander Marshack, in a controversial reading, believed that marks on a bone baton ( c. 25, 000 BC ) represented a lunar calendar.

Similarly, Michael Rappenglueck believes that marks on a 15, 000-year old cave painting represent a lunar calendar.

A lunisolar calendar is a lunar calendar that compensates by adding an extra month as needed to realign the months with the seasons.

In a lunar calendar, the month approximates the cycle of the moon phase.

The same applies to months in a lunar calendar and also the number of months in a year in a lunisolar calendar.

Even if a calendar is solar, but not lunar, the year cannot be divided entirely into months that never vary in length.

The Islamic calendar or Muslim calendar or Hijri calendar is a lunar calendar consisting of 12 lunar months in a year of 354 or 355 days.

The measured brightness temperature is a good approximation to the brightness temperature at the center of the lunar disk because of the narrow antenna beam and because the temperature distribution over the central portion of the moon's disk is nearly uniform.

The south tides in the Atlantic Ocean are semi-diurnal ; that is, two high tides occur during each 24 lunar hours.

* 1958 – Pioneer 0, America's first attempt at lunar orbit, is launched using the first Thor-Able rocket and fails.

Geologists believed prior to the mission that both of these formations were volcanic in origin ; however, samples returned from the lunar surface have since proven this hypothesis is incorrect.

The insignia of Apollo 16 is dominated by rendering of an American eagle and a red, white and blue shield, representing the people of the United States, overlaying a gray background, the lunar surface.

Oh, that first foot on the lunar surface is super, Tony!

It is based on cycles of years, lunar months, and two-hour periods of the day ( the shichen ).

The parallax angle is given in the box to the right, and the angular diameter is known from lunar occultation measurements ( 41. 3 ± 0. 1 mas ).

Antares B can be observed with a small telescope for a few seconds during lunar occultations while Antares itself is hidden by the Moon ; it was discovered by Johann Tobias Bürg during one such occultation on April 13, 1819.

* Balboa ( lunar crater ), a lunar crater that is located near the western limb of the Moon

* The week cycle is an example of one that is not synchronized to any external phenomenon ( although it may have been derived from lunar phases, beginning anew every month ).

Being a purely lunar calendar, it is not synchronized with the seasons.

Being a purely lunar calendar, it is not synchronized with the seasons.

Calendars that are not solar calendars include the Islamic calendar, which is a purely lunar calendar and calendars synchronized to the synodic period of Venus or to the heliacal risings of stars.

The lunar tide and solar tide are synchronized ( ebb and flow at the same time ) near the full moon and the new moon.

Reasons for the use of lunar measurements were practically based: the Moon moves against the background of stars about 13 times as fast as the Sun's corresponding rate of motion, and the accuracy of time determinations from lunar measurements is correspondingly greater.

Motions below the lunar sphere were seen as imperfect, and thus could not be expected to exhibit consistent motion.

To that end, Kepler composed an essay — dedicated to Ferdinand — in which he proposed a force-based theory of lunar motion: " In Terra inest virtus, quae Lunam ciet " (" There is a force in the earth which causes the moon to move ").

A combination of lunar gravity, solar gravity, and the flattening of the Earth at its poles causes a precession motion of the orbital plane of any geostationary object, with a period of about 53 years and an initial inclination gradient of about 0. 85 degrees per year, achieving a maximum inclination of 15 degrees after 26. 5 years.

* The third also completes its revolution in a month, but its axis is tilted at a slightly different angle, explaining motion in latitude ( deviation from the ecliptic ), and the motion of the lunar nodes.

* 1150s – Bhaskara calculates the planetary mean motion, ellipses, first visibilities of the planets, the lunar crescent, the seasons, and the length of the Earth's revolution around the Sun to 9 decimal places.

* c. 1350 – Ibn al-Shatir anticipates Copernicus by abandoning the equant of Ptolemy in his calculations of planetary motion, and he provides the first empirical model of lunar motion which accurately matches observations

The study of the Antikythera Mechanism proves that the ancients have been using very accurate calendars based on all the aspects of solar and lunar motion in the sky.

In fact the Lunar Mechanism which is part of the Antikythera Mechanism depicts the motion of the Moon and its phase, for a given time, using a train of four gears with a pin and slot device which gives a variable lunar velocity that is very close to the second law of Kepler, i. e. it takes into account the fast motion of the Moon at perigee and slower motion at apogee.

It provided data for studies of the interaction of the earth and lunar masses, the lunar gravitational field, the propagation and stability of radio communications to the spacecraft at different orbital positions, solar charged particles and cosmic rays, and the motion of the Moon.

In the 14th century, Ibn al-Shatir produced the first model of lunar motion which matched physical observations, and which was later used by Copernicus.

* Books IV and V cover the motion of the Moon, lunar parallax, the motion of the lunar apogee, and the sizes and distances of the Sun and Moon relative to the Earth.

In actuality, the round-trip time of about 2½ seconds is affected by the relative motion of the Earth and the Moon, the rotation of the Earth, lunar libration, weather, polar motion, propagation delay through Earth's atmosphere, the motion of the observing station due to crustal motion and tides, velocity of light in various parts of air and relativistic effects.