Asterism - Asterism For the patterns of stars in Earth's sky, see constellation. For a list of asterisms, see list of constellations. In jewelry, an asterism is an optical phenomenon displayed by some rubies, sapphires, and other gems of an enhanced reflective area in the shape of a "star" on the surface of a cabochon cut from the stone. This is caused by small needles of rutile (titanium oxide) in the gem. The stars may have six rays or twelve. The rays are reflections from the rutile crystal. Rutile can also cause a "cat's eye" effect in gemstones..
Vela (constellation) - the stars Delta Velorum and Kappa Velorum which together with Iota Carinae and Epsilon Carinae form the asterism known as the "false cross", which is sometimes mistaken for the Southern Cross. Also of interest within the constellation is the Vela Supernova Remnant. This is the nebula of a supernova explosion which is believed to have been visible from the Earth around 10000 years ago. The remant contains a pulsar which was the first pulsar to be identified optically apart from that in the Crab Nebula..
Vulpecula - constellations • Cygnus • Lyra • Hercules • Sagitta • Delphinus • Pegasus Vulpecula, the Fox, is a faint northern constellation located in the middle of the Summer Triangle, an asterism consisting of the stars Deneb, Vega and Altair. Table of contents showTocToggle("show","hide") 1 Notable features 2 Notable deep sky objects 3 History 4 External Links Notable features There are no stars brighter than 4th magnitude in this constellation. The least faint one is Anser (α Vul), a red giant (spectral type M0 III) at a distance of 297 light-years with an apparent magnitude of 4.44. Anser is an optical binary (separation of 413.7") that can be split using binoculars. The second star is 8 Vul. In 1967, the first pulsar, PSR 1919+21, was discovered in this little constellation by Antony Hewish.
Feng Shui - were oriented to catch the midafternoon winter sun at its warmest, just after the solstice. (Some tribes in southern China still refer to this month as "House-building Month.") Professor David Pankenier and his associates performed retrospective computation on the Chinese sky at the time of the Banpo dwellings (4000 BCE) to show that the asterism Yingshi ("Lay out the Hall" in the Warring States period and early Han era) corresponded to the sun's location at this time. Several hundred years earlier the asterism Yingshi was known as Ding. It was used to indicate the appropriate time to build a capital city, according to the Shijing. The grave at Puyang (4,000 BCE) that contains mosaics of the Dragon and Tiger constellations and Beidou (Big Dipper) is similarly oriented with cosmological accuracy along.
Ursa Major - in Latin, and is derived from the legend of Callisto. Its seven brightest stars form a famous asterism known in North America as the Big Dipper, because the major stars can be seen to follow the rough outline of a large ladle, or dipper; this is recognized as a grouping of stars in many cultures throughout the eras. In the United Kingdom it is commonly known as the Plough, and was sometimes called by the old name King Charles's Wain ('wain' meaning 'wagon'). Ursa Major Abbreviation UMa Genitive Ursae Majoris Meaning in English the Great Bear Right ascension 10.67 h Declination 55.38° Visible to latitude Between 90° and -30° On meridian 9 p.m., April 20 Area - Total Ranked 3rd 1 280 sq. deg. Number of stars with apparent magnitude <.
Ursa Minor - one of the 48 listed by Ptolemy. It is notable as the location of the north celestial pole, although this will change after some centuries due to the effects of precession. Table of contents showTocToggle("show","hide") 1 Notable features 2 Mythology 3 History Notable features Ursa Minor contains an asterism colloquially known as the "Little Dipper" because its brightest stars seem to form a ladle, or dipper shape. The star at the end of the dipper handle is Polaris, the "North" or "Pole Star". Polaris, can also be found by following a line through the two stars which form the end of the "bowl" of the Big Dipper, a nearby asterism found in the constellation Ursa Major. Mythology One of Artemis' companions, Callisto, lost her virginity to Zeus, who had come disguised.
Delphinus (constellation) - Notable features 2 Notable deep sky objects 3 History 4 Mythology Notable features Here are some of its stars: Sualocin (α Delphini): B9 IV, 3.77m (multiple star system with 6 components) Rotanev (β Del): F5 IV, 3.63m γ Delphini: one of the finest double stars in the sky. γ1 Delphini: F7 V, 5.14m γ2 Delphini: K1 IV, 4.27m δ Delphini: A7 IIIp, 4.43m The above mentioned stars form an asterism called Job's Coffin. Deneb Dulfim (the tail of the Dolphin) or ε Delphini is a star of spectral class B6 III with a magnitude of 4 R Delphini: Mira-type variable star with a period of 285.5 days; magnitude range between 7.6 and 13.8 Notable deep sky objects NGC 6891: Planetary nebula; 10.5m NGC 6934: This globular cluster is of magnitude 9.75 NGC 7006: at a distance of.
Alniyat - τ. They are perceived as a pair because they are fainter stars of roughly equal brightness flanking the bright start Antares (an asterism similar to that formed by Altair with its neighbours in the constellation of Aquila). The use of a single proper name for two widely separated stars is potentially confusing. The bright star catalog shows a preference for applying this proper name to σ Sco rather than to τ Sco..
Andromeda (constellation) - straggly letter "A". It is most notable for containing the Andromeda Galaxy. Table of contents showTocToggle("show","hide") 1 Notable features 2 Notable deep sky objects 3 Mythology Notable features The brightest star in Andromeda, α Andromedae, called Alpheratz or Sirrah, makes up with α, β, and λ Pegasi an asterism called the Great Square of Pegasus. This star was once considered part of Pegasus, as confirmed by its name, "shoulder of the horse." β Andromedae is called Mirach, the girdle. It is 88 light years distant and of magnitude 2,1. γ Andromedae, or Almach, is found at the tip of the southern leg of the big "A". It is a beautiful multiple star with contrasting colours. υ Andromedae has a planetary system with three confirmed planets, 0.71 times, 2.11 times, and 4.61.
Aquarius - objects 3 History 4 Mythology 5 Astrology Notable features Some principal stars in Aquarius include: α Aquarii, Sadalmelik ("lucky one of the king"), found nearly on the celestial equator; β Aquarii, Sadalsud ("luckiest of the lucky"); γ Aquarii, Sadachbia ("lucky star of hidden things"); δ Aquarii, Skat or Scheat ("shin"). The stars γ, ζ, η, and π Aquarii compose an asterism called the Urn, representing Aquarius' watering pot. Two meteor showers originate in Aquarius: the Eta Aquarids (near May 4) and the Delta Aquarids (near June 28), both providing about 20 meteorites per hour. Notable deep sky objects There are two deep sky objects which is on the Messier catalog, the globular cluster M72 and the open cluster M73. Two planetary nebulae are found in Aquarius: NGC 7009, called the Saturn.
Chatoyancy - of the fibres. For a gemstone to show this effect it must be cut en cabochon, with the fibres or fibrous structures parallel to the base of the finished stone. Some gem species known for this phenomenon include the aforementioned quartz, chrysoberyl, beryl (especially var. aquamarine), tourmaline, apatite, and scapolite. See also: asterism, optical phenomenon References Webster, R., Jobbins, E. A. (Ed.). (1998). Gemmologist's compendium. St Edmundsbury Press Ltd, Bury St Edwards..
Constellation - imaginary plane of the night sky. Humans excel at finding patterns and throughout history have grouped stars that appear close to one another into constellations. An "unofficial" constellation is also called an asterism. The stars in a constellation or asterism rarely have any astrophysical relationship to each other; they just happen to appear close together from Earth and typically lie very far apart in space. The grouping of stars into constellations is essentially arbitrary, and different cultures have had different constellations, although a few of the more obvious ones tend to recur frequently, e.g Orion and Scorpius. The International Astronomical Union (IAU) divides the sky into 88 official constellations with precise boundaries, so that every direction belongs to exactly one constellation. These are mostly based upon the constellations of the ancient.
Coma Berenices - 4.3 Meteor showers Coma Berenicids Bordering constellations Canes Venatici Ursa Major Leo Virgo Boötes Coma Berenices (Berenice's Hair) is a traditional asterism that has since become a constellation. It is located near Leo. Table of contents showTocToggle("show","hide") 1 Notable features 2 Notable deep sky objects 3 History and Mythology Notable features The brightest star in Coma Berenices (α Comae Berenices) is named Diadem; it represents the gem in Berenice's crown. β Comae Berenices is a little brighter than our Sun, which gives us an idea of how faint the Sun would appear seen from only 27 light years away. Notable deep sky objects Most of Coma Berenices' stars constitute an open cluster which is not listed in most catalogues because it is spread over a huge region, more than 5 degrees.
Corvus (constellation) - 3.00 140 α Al Chiba, Al Minliar al Ghurab, Alchiba, Alchita, Alkhiba, HD105452 4.02 49 ζ HD107348 5.2 13.7 360 Double star. VV Struve 1669, ADS 8627 6.0 6.0 278 Quadruple. R 6.7 / 14.4 Variable star with a 317.03 day cycle. Ross 695, HIP 60559 12.4 29.64 Very close to Sol, with a proper motion of 2.52 seconds of arc per year. δ, γ, ε, and β form the 'sail' asterism; and γ and δ serve as pointers toward (Spica). Mythology In Greek mythology the crow is sent to fetch a cup (Crater (constellation)) of water but instead returns with a water snake (Hydra (constellation))..
Sagittarius - to the west and Capricornus to the east. Its brighter stars form an easily recognizable teapot shape. Table of contents showTocToggle("show","hide") 1 Notable features 2 Notable deep-sky objects 3 Mythology 3.1 Astrology Notable features The constellation is easily recognizable through an asterism called the Teapot. The stars Kaus Media (δ), Kaus Australis (ε), Ascella (ζ), and φ Sagitarii form the body of the pot, Kaus Borealis (λ) is the point of the elid, Alnasl (γ) is the tip of the spout, and Nunki (σ) and τ Sagitarii are the handle. The α star, Rukbat, is nowhere near the brightest star of the constellation, having a magnitude of only 4,0. Notable deep-sky objects The Milky Way is at its densest as it passes through Sagittarius, as this is where the galactic centre.
Summer Triangle - Summer Triangle The Summer Triangle is an astronomical asterism involving an imaginary triangle drawn, during the summer, upon the northern hemisphere's celestial sphere; with its defining vertices at Altair, Deneb, and Vega. This triangle connects the constellations of Aquila, Cygnus, and Lyra. See also: Winter Triangle Chinese Valentine's Day.
Rutile - lower temperatures. Rutile is found as an accessory mineral in many kinds of igneous rocks, and to some extent in gneisses and schists. In groups of acicular crystals it is frequently seen penetrating quartz as in the "fléches d'amour" from Grisons, Switzerland. Small rutile needles present in gems are responsible for "star" sapphires, "star" rubies and other "star" gems, an optical phenomenon known as asterism. Synthetic rutile was first produced in 1948 and is sold under a variety of names. It has very high dispersion and refracts light so strongly that it looks phoney, being very colorful. Synthetic rutile can be made in a variety of colors, but not a pure transparent white, being always slightly yellow. Because of its phoney appearance it is seldom used in jewellery. It is not.
Pegasus (constellation) - also one of the 48 constellations listed by Ptolemy. Its three brightest stars together with Alpha Andromedaee form the large asterism known as the Square of Pegasus. A star in this constellation, 51 Pegasi, is orbited by the first true extrasolar planets (planets orbiting a star other than the Sun) to have been discovered. Neighbouring constellations: Vulpecula - Delphinus - Equuleus - Aquarius - Pisces - Andromeda - Lacerta - Cygnus.
Plough - Plough For the asterism known as "The Plough"...see: Ursa Major. The plough (American spelling: plow) is a tool used in farming for turning the earth in which one is to plant new seeds. The plough is a development of the pick, and was initially pulled by oxen or humans, and later horses. Modern ploughs are, in industrialized countries, powered by tractors. Ploughing has several beneficial effects. The major reason for ploughing is to incorporate the residue from the previous crop into the soil. Ploughing also reduces the prevalence of weeds in the fields, and makes the soil more porous, easing later planting. The early German word before sound-shift is plug and in Old Prussian plugis. After the German sound shift (p = pf) it became the modern.
Open cluster - but short-lived. Analysing the light from an open cluster one can estimate its age, looking at ratio between blue, yellow and red stars. The more blue stars there are, the younger the cluster is. The uniformity between the cluster's stars makes them a perfect test for stellar evolution models, because when comparing one star to the other, most of the variable parameters are now fixed. Testing the model is therefore easier. The closest open cluster is in Ursa Major, or to be more correct, it is Ursa Major. Most of the stars in the famous asterism are members of an old and mostly dispersed open cluster. Sirius is a former member of this cluster and our sun is in the outskirts of what is called The Ursa Major Stream, a group.
