Aries (constellation) in the context of First Point of Aries

The zodiac is a belt-shaped region of the sky that extends approximately 8° north and south celestial latitude of the ecliptic – the apparent path of the Sun across the celestial sphere over the course of the year. Within this zodiac belt appear the Moon and the brightest planets, along their orbital planes. The zodiac is divided along the ecliptic into 12 equal parts, called "signs", each occupying 30° of celestial longitude. These signs roughly correspond to the astronomical constellations with the following modern names: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces.

The signs have been used to determine the time of the year by identifying each sign with the days of the year the Sun is in the respective sign. In Western astrology, and formerly astronomy, the time of each sign is associated with different attributes. The zodiacal system and its angular measurement in 360 sexagesimal degree (°) originated with Babylonian astronomy during the 1st millennium BC, probably during the Achaemenid Empire. It was communicated into Greek astronomy by the 2nd century BC, as well as into developing the Hindu zodiac. Due to the precession of the equinoxes, the time of year that the Sun is in a given constellation has changed since Babylonian times, and the point of March equinox has moved from Aries into Pisces.

Perseus is a constellation in the northern sky, named after the Greek mythological hero Perseus. It is one of the 48 ancient constellations listed by the 2nd-century astronomer Ptolemy, and among the 88 modern constellations defined by the International Astronomical Union (IAU). It is located near several other constellations named after ancient Greek legends surrounding Perseus, including Andromeda to the west and Cassiopeia to the north. Perseus is also bordered by Aries and Taurus to the south, Auriga to the east, Camelopardalis to the north, and Triangulum to the west. Some star atlases during the early 19th century also depicted Perseus holding the disembodied head of Medusa, whose asterism was named together as Perseus et Caput Medusae; however, this never came into popular usage.

The galactic plane of the Milky Way passes through Perseus, whose brightest star is the yellow-white supergiant Alpha Persei (also called Mirfak), which shines at magnitude 1.79. It and many of the surrounding stars are members of an open cluster known as the Alpha Persei Cluster. The best-known star, however, is Algol (Beta Persei), linked with ominous legends because of its variability, which is noticeable to the naked eye. Rather than being an intrinsically variable star, it is an eclipsing binary. Other notable star systems in Perseus include X Persei, a binary system containing a neutron star, and GK Persei, a nova that peaked at magnitude 0.2 in 1901. The Double Cluster, comprising two open clusters quite near each other in the sky, was known to the ancient Chinese. The constellation gives its name to the Perseus Cluster (Abell 426), a massive galaxy cluster located 250 million light-years from Earth. It hosts the radiant of the annual Perseids meteor shower—one of the most prominent meteor showers in the sky.

Aries (♈︎; Ancient Greek: Κριός, romanized: Kriós, Latin: Ariēs, lit. 'ram') is the first astrological sign in the zodiac, spanning the first 30 degrees of celestial longitude (0°≤ λ <30°), and originates from the Aries constellation. Under the tropical zodiac, the Sun transits this sign from approximately March 21 to April 20 each year. This time-duration is exactly the first month of the Solar Hijri calendar (Arabic: Hamal; Persian: Farvardin; Pashto: Wray).

According to the tropical system of astrology, the Sun enters the sign of Aries when it reaches the March equinox, typically on March 21. Because the Earth takes approximately 365.24 days to go around the Sun, the precise time of the equinox is not the same each year, and generally will occur about six hours later from one year to the next until reset by a leap year. The leap day February 29 causes that year's March equinox to fall about eighteen hours earlier compared with the previous year.

Pisces is a constellation of the zodiac. Its vast bulk — and main asterism viewed in most European cultures per Greco-Roman antiquity as a distant pair of fishes connected by one cord each that join at an apex — are in the Northern celestial hemisphere. Its traditional astrological symbol is (♓︎). Its name is Latin for "fishes". It is between Aquarius, of similar size, to the southwest and Aries, which is smaller, to the east. The ecliptic and the celestial equator intersect within this constellation and in Virgo. The Sun passes directly overhead of the equator, on average, at approximately this point in the sky, at the March equinox.

The right ascension/declination 00 is located within the boundaries of Pisces.

Nakshatra (Sanskrit: नक्षत्रम्, romanized: Nakṣatram) is the term for Lunar mansion in Hindu astrology and Buddhist astrology. A nakshatra is one of the 27 (sometimes also 28) sectors along the ecliptic. Their names are related to a prominent star or asterisms in or near the respective sectors. In essence (in Western astronomical terms), a nakshatra simply is a constellation. Every nakshatra is divided into four padas (lit. "steps").

The starting point for the nakshatras according to the Vedas is "Krittika" (it has been argued, because the Pleiades may have started the year at the time the Vedas were compiled, presumably at the vernal equinox), but, in more recent compilations, the start of the nakshatras list is the point on the ecliptic directly opposite the star Spica, called Chitrā in Sanskrit. This translates to Ashwinī, a part of the modern constellation of Aries. These compilations, therefore, may have been compiled during the centuries when the sun was passing through Aries at the time of the vernal equinox. This version may have been called Meshādi or the "start of Aries".

Vaisakha (Sanskrit: वैशाख, IAST: Vaiśākha) is the second month of the Hindu lunar calendar and the Indian national calendar. The name of the month is derived from the position of the Moon near the Vishākhā nakshatra (star) on the full moon day. It corresponds to April–May in the Gregorian calendar. The month corresponds to the end of the spring (Vasanta) season and falls in April–May of the Gregorian calendar.

In the Hindu solar calendar, it corresponds to the month of Mesha and begins with the Sun's entry into Aries. It corresponds to Boishakh, the first month in the Bengali calendar. In the Tamil calendar, it corresponds to the third month of Vaikasi, falling in the Gregorian months of May–June. In the Vaishnav calendar, it corresponds to the third month of Madhusudanah.

The first point of Aries, also known as the cusp of Aries or the vernal point, is the location of the March equinox (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 ♈︎. Named for the constellation of Aries, it is one of the two points on the celestial sphere at which the celestial equator crosses the ecliptic, the other being the first point of Libra, located exactly 180° from it. Due to precession of the equinoxes since the positions were originally named in antiquity, the position of the Sun when at the March equinox is now in Pisces; when it is at the September equinox, it is in Virgo (as of J2000).

Along its yearly path through the zodiac, the Sun meets the celestial equator as it travels from south to north at the first point of Aries, and from north to south at the first point of Libra. The first point of Aries is considered to be the celestial "prime meridian" from which right ascension is calculated.

Hamal, pronounced /ˈhæməl/, is a star in the northern zodiacal constellation of Aries. It has the Bayer designation Alpha Arietis, which is Latinized from α Arietis and abbreviated Alpha Ari or α Ari. This star is visible to the naked eye with an apparent visual magnitude of 2.0. Hamal is the brightest star in the constellation and, on average, the 50th-brightest star in the night sky. Based upon parallax measurements made with the Hipparcos astrometry satellite, Hamal is about 65.8 light-years (20.2 parsecs) from Earth. It is drifting closer to the Sun with a radial velocity of −14 km/s.

This is an aging giant star that is likely to host an orbiting planet with a mass greater than Jupiter.

Beta Arietis is a binary star system in the constellation of Aries, marking the ram's second horn. Its identifier is a Bayer designation that is Latinized from β Arietis, and abbreviated Beta Ari or β Ari. It has the official name Sheratan, pronounced /ˈʃɛrətæn/. This system is visible to the naked eye as a point of light with a combined apparent visual magnitude of 2.65, making this the second-brightest star in the constellation. Located at a distance of 58.4 light-years (17.9 pc), the pair orbit each other with a period of 107 days.

Gamma Arietis is a binary or possibly trinary star system in the northern constellation of Aries. Its name is a Bayer designation that is Latinized from γ Arietis, and abbreviated Gamma Ari or γ Ari. This system is called "The First Star in Aries" as having been at one time the nearest visible star to the equinoctial point. The combined apparent visual magnitude of the stars is 3.86, which is readily visible to the naked eye and makes this the fourth-brightest member of Aries. Based upon parallax measurements, the distance to Gamma Arietis from the Sun is approximately 166 light-years (51 parsecs).

The two components are designated γ Arietis or Gamma Arietis B and γ Arietis or Gamma Arietis A. The latter is formally named Mesarthim, pronounced /mɛˈsɑːrθɪm/, the traditional name for the Gamma Arietis system. γ Arietis may itself be a spectroscopic binary with a low mass companion.

41 Arietis (abbreviated 41 Ari) is a triple star system in the northern constellation of Aries. With an apparent visual magnitude of 3.63, this system is readily visible to the naked eye. It has an annual parallax shift of 19.69 mas, which indicates it is at a distance of 166 light-years (51 parsecs) from the Sun.

The system consists of a binary pair, designated 41 Arietis A, together with a third companion star, 41 Arietis D. (41 Arietis B and C form optical pairs with A, but are not physically related.) The components of A are themselves designated 41 Arietis Aa (formally named Bharani /ˈbærəni/) and Ab.

The Arietids are a strong meteor shower that lasts from May 22 to July 2 each year, and peaks on June 7. The Arietids, along with the Zeta Perseids, are the most intense daylight meteor showers of the year. The source of the shower is unknown, but scientists suspect that they come from the asteroid 1566 Icarus, although the orbit also corresponds similarly to 96P/Machholz.

First discovered at Jodrell Bank Observatory in England during the summer of 1947, the showers are caused when the Earth passes through a dense portion of two interplanetary meteoroid streams, producing an average of 60 shooting stars each hour, that originate in the sky from the constellation Aries and the constellation Perseus. However, because both constellations are so close to the Sun when these showers reach their peak, the showers are difficult to view with the naked eye. Some of the early meteors are visible in the very early hours of the morning, usually an hour before dawn. The meteors strike Earth's atmosphere at speeds around 39 km/s.