Triangulum
Encyclopedia
Triangulum is a small constellation
in the northern sky. Its name is Latin
for triangle
, and it should not be confused with Triangulum Australe
in the southern sky. Its name derives from its three brightest star
s, of third and fourth magnitude
, which form a nearly isosceles long and narrow triangle
. Triangulum was one of the 48 constellations listed by the 2nd century astronomer Ptolemy
, and remains one of the 88 modern constellations.
. Its brightest star is the white giant star β Trianguli
(3.00m) with a close, dimmer companion. Its second-brightest star, the yellow-white subgiant star α Trianguli
(3.41m) with a close dimmer companion, is also known as Caput Trianguli, and is at the apex of the triangle
. 6 Trianguli, (known in some older sources as ι), is an "attractive double star with a noticeable color contrast" that can be split by medium-sized telescopes into a strong yellow and a pale blue star. Both components are themselves close binaries.
, also known as Messier 33. A distant member of the Local Group
, it is about 2.9 million light years away, and at magnitude 5.8, it is bright enough to be seen by the naked eye under the darkest skies. Under light-polluted skies, it is challenging or invisible even in a small telescope or binoculars. Because of its low surface brightness, low power is required.
In addition to M33, there are several NGC galaxies, all with magnitudes fainter than 11. The largest of these include the 10 arcminute long magnitude 12 NGC 925
spiral galaxy and the 5 arcminute long magnitude 11.6 NGC 672 barred spiral galaxy.
, Triangulum together with γ And formed the constellation known as MULAPIN "The Plough". It is notable as the first constellation listed in the pair of tablets containing the canonical star lists compiled around 1000 BC, which are thus known as the MUL.APIN
by their incipit. The Plough was the first constellation of the "Way of Enlil
", i.e. northernmost quarter of the Sun's path, corresponding to the 45 days on either side of summer solstice
.
An early name of the constellation was Sicilia, because Ceres, patron goddess of Sicily
, was claimed to have begged Jupiter
that the island be placed in the heavens.
The Greeks called Triangulum Δελτωτόν, as the constellation resembled an upper-case Greek letter delta (Δ) to the earlier Greeks. It was transliterated into Deltoton by Roman writers. Later, it became Latin form, Deltotum. Greek astromoers called it as Τρίγωον. And later, it became Trigonum.
was a United States Navy
Crater class cargo ship
named after the constellation.
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
in the northern sky. Its name is Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for triangle
Triangle
A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A, B, and C is denoted ....
, and it should not be confused with Triangulum Australe
Triangulum Australe
Triangulum Australe is a small constellation in the southern sky, created in the sixteenth century. Its name is Latin for 'the southern triangle', which distinguishes it from Triangulum in the northern sky...
in the southern sky. Its name derives from its three brightest star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s, of third and fourth magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
, which form a nearly isosceles long and narrow triangle
Triangle
A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A, B, and C is denoted ....
. Triangulum was one of the 48 constellations listed by the 2nd century astronomer Ptolemy
Ptolemy
Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...
, and remains one of the 88 modern constellations.
Stars
Triangulum has no stars of the first magnitudeApparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
. Its brightest star is the white giant star β Trianguli
Beta Trianguli
Beta Trianguli is the brightest star in the constellation Triangulum.In Chinese traditional astronomy, it was the 9th star of Tien Ta Tseang ....
(3.00m) with a close, dimmer companion. Its second-brightest star, the yellow-white subgiant star α Trianguli
Alpha Trianguli
Alpha Trianguli is a binary star in the constellation Triangulum. It has the traditional names Mothallah or Ras al Muthallah , and Caput Trianguli, from the Arabic رأس المثلث ra’s al-muθallaθ "the head of the triangle" and its Latin translation.Alpha Trianguli...
(3.41m) with a close dimmer companion, is also known as Caput Trianguli, and is at the apex of the triangle
Triangle
A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A, B, and C is denoted ....
. 6 Trianguli, (known in some older sources as ι), is an "attractive double star with a noticeable color contrast" that can be split by medium-sized telescopes into a strong yellow and a pale blue star. Both components are themselves close binaries.
Deep sky objects
Triangulum is the location of the Triangulum GalaxyTriangulum Galaxy
The Triangulum Galaxy is a spiral galaxy approximately 3 million light years from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC 598, and is sometimes informally referred to as the Pinwheel Galaxy, a nickname it shares with Messier 101...
, also known as Messier 33. A distant member of the Local Group
Local Group
The Local Group is the group of galaxies that includes Earth's galaxy, the Milky Way. The group comprises more than 30 galaxies , with its gravitational center located somewhere between the Milky Way and the Andromeda Galaxy...
, it is about 2.9 million light years away, and at magnitude 5.8, it is bright enough to be seen by the naked eye under the darkest skies. Under light-polluted skies, it is challenging or invisible even in a small telescope or binoculars. Because of its low surface brightness, low power is required.
In addition to M33, there are several NGC galaxies, all with magnitudes fainter than 11. The largest of these include the 10 arcminute long magnitude 12 NGC 925
NGC 925
NGC 925 is a barred spiral galaxy in the constellation Triangulum, about 45 million light-years away.- References :...
spiral galaxy and the 5 arcminute long magnitude 11.6 NGC 672 barred spiral galaxy.
History and mythology
In the Babylonian star cataloguesBabylonian star catalogues
Babylonian astronomy collated earlier observations and divinations into sets of Babylonian star catalogues, during and after the Kassite rule over Babylonia. These star catalogues, written in cuneiform script, contained lists of constellations, individual stars, and planets...
, Triangulum together with γ And formed the constellation known as MULAPIN "The Plough". It is notable as the first constellation listed in the pair of tablets containing the canonical star lists compiled around 1000 BC, which are thus known as the MUL.APIN
MUL.APIN
MUL.APIN is the conventional title given to a Babylonian compendium that deals with many diverse aspects of Babylonian astronomy and astrology....
by their incipit. The Plough was the first constellation of the "Way of Enlil
Enlil
Elizabeth Barrett Browning was one of the most prominent poets of the Victorian era. Her poetry was widely popular in both England and the United States during her lifetime. A collection of her last poems was published by her husband, Robert Browning, shortly after her death.-Early life:Members...
", i.e. northernmost quarter of the Sun's path, corresponding to the 45 days on either side of summer solstice
Summer solstice
The summer solstice occurs exactly when the axial tilt of a planet's semi-axis in a given hemisphere is most inclined towards the star that it orbits. Earth's maximum axial tilt to our star, the Sun, during a solstice is 23° 26'. Though the summer solstice is an instant in time, the term is also...
.
An early name of the constellation was Sicilia, because Ceres, patron goddess of Sicily
Sicily
Sicily is a region of Italy, and is the largest island in the Mediterranean Sea. Along with the surrounding minor islands, it constitutes an autonomous region of Italy, the Regione Autonoma Siciliana Sicily has a rich and unique culture, especially with regard to the arts, music, literature,...
, was claimed to have begged Jupiter
Jupiter (mythology)
In ancient Roman religion and myth, Jupiter or Jove is the king of the gods, and the god of the sky and thunder. He is the equivalent of Zeus in the Greek pantheon....
that the island be placed in the heavens.
The Greeks called Triangulum Δελτωτόν, as the constellation resembled an upper-case Greek letter delta (Δ) to the earlier Greeks. It was transliterated into Deltoton by Roman writers. Later, it became Latin form, Deltotum. Greek astromoers called it as Τρίγωον. And later, it became Trigonum.
Namesakes
USS Triangulum (AK-102)USS Triangulum (AK-102)
USS Triangulum was an Crater-class cargo ship commissioned by the U.S. Navy for service in World War II. She was responsible for delivering troops, goods and equipment to locations in the war zone....
was a United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
Crater class cargo ship
Crater class cargo ship
Crater-class cargo ship is a category of freighter that was constructed for use by the United States Navy during World War II under Maritime Commission EC2-S-C1 type....
named after the constellation.