Aries (constellation)Aries is one of the constellations of the zodiac. It is located in the Northern celestial hemisphere between Pisces to the west and Taurus to the east. The name Aries is Latin for ram. Its traditional astrological symbol is (♈︎). It is one of the 48 constellations described by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations.
Aquarius (constellation)Aquarius is an equatorial constellation of the zodiac, between Capricornus and Pisces. Its name is Latin for "water-carrier" or "cup-carrier", and its traditional astrological symbol is (♒︎), a representation of water. Aquarius is one of the oldest of the recognized constellations along the zodiac (the Sun's apparent path). It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations.
First point of AriesThe first point of Aries, also known as the cusp of Aries or the vernal point, is the location of the Marchequinox (the vernal equinox in the northern hemisphere, and the autumnal equinox in the southern), used as a reference point in celestial coordinate systems. In diagrams using such coordinate systems, it is often indicated with the symbol ♈︎.
Northern celestial hemisphereThe northern celestial hemisphere, also called the Northern Sky, is the northern half of the celestial sphere; that is, it lies north of the celestial equator. This arbitrary sphere appears to rotate westward around a polar axis due to Earth's rotation. At any given time, the entire Northern Sky is visible from the geographic North Pole, while less of the hemisphere is visible the farther south the observer is located.
ZodiacArea of the sky divided into twelve signsThe Earth's orbit around the Sun causes the apparent motion of the latter along the ecliptic (red).
Right ascensionIn astronomy, Right ascension (abbreviated RA; symbol α) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point in question above the Earth. When paired with declination, these astronomical coordinates specify the location of a point on the celestial sphere in the equatorial coordinate system.
Virgo (constellation)Virgo is one of the constellations of the zodiac. The name means "maiden" in Latin and its traditional astrological symbol is . Between Leo to the west and Libra to the east, lying in the south, it is the second-largest constellation in the sky (after Hydra) and the largest constellation in the zodiac. The ecliptic intersects the celestial equator within this constellation and Pisces.
Celestial equatorThe celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of a planet, by convention generally Earth. By extension, it is also a plane of reference in the equatorial coordinate system.
EclipticThe ecliptic or ecliptic plane is the apparent path of the Sun on the celestial sphere, resulting from Earth's orbit around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. The ecliptic is so named because the ancients noted that eclipses only occur when the Moon is crossing it.
Subsolar pointThe subsolar point on a planet or a moon is the point at which its Sun is perceived to be directly overhead (at the zenith); that is, where the Sun's rays strike the planet exactly perpendicular to its surface. The subsolar point occurs at the location on a planet or a moon where the Sun culminates at the location's zenith. This occurs at solar noon.
March equinoxThe March equinox or northward equinox is the equinox on the Earth when the subsolar point appears to leave the Southern Hemisphere and cross the celestial equator, heading northward as seen from Earth. The March equinox is known as the vernal equinox (or spring equinox) in the Northern Hemisphere and as the autumnal equinox in the Southern Hemisphere. On the Gregorian calendar at 0° longitude, the northward equinox usually occurs on March 20.
DeclinationIn astronomy, declination (abbreviated dec; symbol δ) is the angular distance from the celestial equator on the celestial sphere; when paired with right ascension, it forms the equatorial coordinate system. The declination angle is measured north (positive) or south (negative) of the celestial equator, lining up with the hour circle passing through the point in question. The word declination traces roots from (Latin, declinatio), meaning "bending away" or "bending down".
EquinoxA solar equinox is a moment in time when the Sun appears directly above the equator, rather than to its north or south. On the day of the equinox, the Sun rises exactly in the east and sets exactly in the west. This occurs twice each year, around 20 March and 23 September. An equinox is defined as the time when the plane of Earth's equator passes through the geometric center of the Sun's disk.*As an Amazon Associate I earn from qualifying purchases.