26 relations: Angular diameter, Antipodal point, Apparent magnitude, Apparent retrograde motion, Asteroid, Astronomical object, Astronomical symbols, Celestial sphere, Comet, Conjunction (astronomy), Coplanarity, Culmination, Earth, Ecliptic, Ecliptic coordinate system, Full moon, Inferior and superior planets, Lunar eclipse, Moon, Opposition surge, Orbit, Planetary phase, Solar System, Spherical astronomy, Sun, Syzygy (astronomy).
The angular diameter, angular size, apparent diameter, or apparent size is an angular measurement describing how large a sphere or circle appears from a given point of view.
In mathematics, the antipodal point of a point on the surface of a sphere is the point which is diametrically opposite to it — so situated that a line drawn from the one to the other passes through the center of the sphere and forms a true diameter.
The apparent magnitude of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth.
Apparent retrograde motion is the apparent motion of a planet in a direction opposite to that of other bodies within its system, as observed from a particular vantage point.
Asteroids are minor planets, especially those of the inner Solar System.
An astronomical object or celestial object is a naturally occurring physical entity, association, or structure that exists in the observable universe.
Astronomical symbols are symbols used to represent astronomical objects, theoretical constructs and observational events in astronomy.
In astronomy and navigation, the celestial sphere is an abstract sphere with an arbitrarily large radius concentric to Earth.
Christmas is an annual festival commemorating the birth of Jesus Christ,Martindale, Cyril Charles.
The Christmas season, also called the festive season, or the holiday season (mainly in the U.S. and Canada; often simply called the holidays),, is an annually recurring period recognized in many Western and Western-influenced countries that is generally considered to run from late November to early January.
Christmas Eve is the evening or entire day before Christmas Day, the festival commemorating the birth of Jesus.
Christmas traditions vary from country to country.
A comet is an icy small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process called outgassing.
In astronomy, a conjunction occurs when two astronomical objects or spacecraft have either the same right ascension or the same ecliptic longitude, usually as observed from Earth.
In geometry, a set of points in space are coplanar if there exists a geometric plane that contains them all.
In astronomy, the culmination of a planet, star, or constellation is its transit over an observer's meridian.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.
The ecliptic is the circular path on the celestial sphere that the Sun follows over the course of a year; it is the basis of the ecliptic coordinate system.
The ecliptic coordinate system is a celestial coordinate system commonly used for representing the apparent positions and orbits of Solar System objects.
The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective.
In the Solar System, a planet is said to be inferior with respect to another planet if its orbit lies inside the other planet's orbit around the Sun.
A lunar eclipse occurs when the Moon passes directly behind Earth and into its shadow.
The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite.
New Year is the time or day at which a new calendar year begins and the calendar's year count increments by one.
New Year's Day, also called simply New Year's or New Year, is observed on January 1, the first day of the year on the modern Gregorian calendar as well as the Julian calendar.
In the Gregorian calendar, New Year's Eve (also known as Old Year's Day or Saint Sylvester's Day in many countries), the last day of the year, is on 31 December which is the seventh day of Christmastide.
The opposition surge (sometimes known as the opposition effect, opposition spike or Seeliger effect) is the brightening of a rough surface, or an object with many particles, when illuminated from directly behind the observer.
In physics, an orbit is the gravitationally curved trajectory of an object, such as the trajectory of a planet around a star or a natural satellite around a planet.
A planetary phase is a period of time during which a certain portion of a planet's area reflects sunlight from the perspective of a given vantage point.
The Solar SystemCapitalization of the name varies.
Spherical astronomy or positional astronomy is the branch of astronomy that is used to determine the location of objects on the celestial sphere, as seen at a particular date, time, and location on Earth.
The Sun is the star at the center of the Solar System.
In astronomy, a syzygy (from the Ancient Greek σύζυγος suzugos meaning, "yoked together") is a (usually) straight-line configuration of three or more celestial bodies in a gravitational system.
2018 has been designated as the third International Year of the Reef by the International Coral Reef Initiative.
2019 (MMXIX) will be a common year starting on Tuesday of the Gregorian calendar, the 2019th year of the Common Era (CE) and Anno Domini (AD) designations, the 19th year of the 3rd millennium, the 19th year of the 21st century, and the 10th and last year of the 2010s decade.