An astrolabe is an elaborate inclinometer, can be considered an analog calculator capable of working out several different kinds of problems in astronomy. Used by astronomers and navigators to measure the altitude above the horizon of a celestial body, day or night, it can be used to identify stars or planets, to determine local latitude given local time, to survey, or to triangulate, it was used in classical antiquity, the Islamic Golden Age, the European Middle Ages and the Age of Discovery for all these purposes. The astrolabe's importance not only comes from the early development of astronomy, but is effective for determining latitude on land or calm seas. Although it is less reliable on the heaving deck of a ship in rough seas, the mariner's astrolabe was developed to solve that problem. OED gives the translation "star-taker" for the English word astrolabe and traces it through medieval Latin to the Greek word astrolabos, from astron "star" and lambanein "to take". In the medieval Islamic world the Arabic word al-Asturlāb was given various etymologies.

In Arabic texts, the word is translated as a direct translation of the Greek word. Al-Biruni quotes and criticizes medieval scientist Hamzah al-Isfahani who stated: "asturlab is an arabization of this Persian phrase". In medieval Islamic sources, there is a folk etymology of the word as "lines of lab", where "Lab" refers to a certain son of Idris; this etymology is mentioned by a 10th-century scientist rejected by al-Khwarizmi. An early astrolabe was invented in the Hellenistic civilization by Apollonius of Perga between 220 and 150 BC attributed to Hipparchus; the astrolabe was a marriage of the planisphere and dioptra an analog calculator capable of working out several different kinds of problems in astronomy. Theon of Alexandria wrote a detailed treatise on the astrolabe, Lewis argues that Ptolemy used an astrolabe to make the astronomical observations recorded in the Tetrabiblos; the invention of the plane astrolabe is sometimes wrongly attributed to Theon's daughter Hypatia, but it is, in fact, known to have been in use at least 500 years before Hypatia was born.

The misattribution comes from a misinterpretation of a statement in a letter written by Hypatia's pupil Synesius, which mentions that Hypatia had taught him how to construct a plane astrolabe, but does not state anything about her having invented it herself. Astrolabes continued in use in the Greek-speaking world throughout the Byzantine period. About 550 AD, Christian philosopher John Philoponus wrote a treatise on the astrolabe in Greek, the earliest extant treatise on the instrument. Mesopotamian bishop Severus Sebokht wrote a treatise on the astrolabe in the Syriac language in the mid-7th century. Sebokht refers to the astrolabe as being made of brass in the introduction of his treatise, indicating that metal astrolabes were known in the Christian East well before they were developed in the Islamic world or in the Latin West. Astrolabes were further developed in the medieval Islamic world, where Muslim astronomers introduced angular scales to the design, adding circles indicating azimuths on the horizon.

It was used throughout the Muslim world, chiefly as an aid to navigation and as a way of finding the Qibla, the direction of Mecca. Eighth-century mathematician Muhammad al-Fazari is the first person credited with building the astrolabe in the Islamic world; the mathematical background was established by Muslim astronomer Albatenius in his treatise Kitab az-Zij, translated into Latin by Plato Tiburtinus. The earliest surviving astrolabe is dated AH 315. In the Islamic world, astrolabes were used to find the times of sunrise and the rising of fixed stars, to help schedule morning prayers. In the 10th century, al-Sufi first described over 1,000 different uses of an astrolabe, in areas as diverse as astronomy, navigation, timekeeping, Salat, etc; the spherical astrolabe was a variation of both the astrolabe and the armillary sphere, invented during the Middle Ages by astronomers and inventors in the Islamic world. The earliest description of the spherical astrolabe dates back to Al-Nayrizi. In the 12th century, Sharaf al-Dīn al-Tūsī invented the linear astrolabe, sometimes called the "staff of al-Tusi", "a simple wooden rod with graduated markings but without sights.

It was furnished with a plumb line and a double chord for making angular measurements and bore a perforated pointer". The geared mechanical astrolabe was invented by Abi Bakr of Isfahan in 1235; the first known metal astrolabe in Western Europe is the Destombes astrolabe made from brass in eleventh century in Portugal. Metal astrolabes avoided the warping that large wooden ones were prone to, allowing the construction of larger and therefore more accurate instruments. Metal astrolabes were heavier than wooden instruments of the same size, making it difficult to use them in navigation. Herman Contractus, the abbot of Reichman Abbey, examined the use of the astrolabe in Mensura Astrolai during the 11th century. Peter of Maricourt wrote a treatise on the construction and use of a universal astrolabe in the last half of the 13th century entitled Nova compositio astrolabii particularis. Universal astrolabes can be found at the History of Science Museum in Oxford. David A. King, historian of Islamic instrumentation, describes the universal astrolobe designed by Ibn al-Sarraj of Aleppo

Order of the Hero of Socialist Labour

Order of the Hero of Socialist Labour was the fourth highest state decoration awarded in Yugoslavia. It was awarded to Yugoslav citizens and sports teams for outstanding achievements in their professional work; the order was awarded a total of 121 times until 1987. After the dissolution of SFR Yugoslavia the decoration was discontinued. Along with the order, the recipient was awarded the title of Hero of Socialist Labour; the Order of the Hero of Socialist Labour was formally established on 8 December 1948 as the Yugoslav equivalent to the Soviet title of Hero of Socialist Labour. The order was bestowed by the President of Yugoslavia. First recipient of the order was Moša Pijade, in 1949. Only two people were awarded the order twice - Đuro Pucar. Five women received the award - Spasenija Cana Babović, Anka Berus, Lidija Šentjurc, Vida Tomšič and Ida Sabo; the only foreigner who received the award was President of Romania and General Secretary of the Romanian Communist Party, Nicolae Ceaușescu, who received the award in January 1978.

The Order was awarded a total of 121 times until 1987. Some of the notable recipients are: Orders and medals of SFR Yugoslavia

David Hockney

David Hockney, is a British painter, printmaker, stage designer, photographer. As an important contributor to the pop art movement of the 1960s, he is considered one of the most influential British artists of the 20th century. Hockney has owned a home and studio in Bridlington and London, two residences in California, where he has lived on and off since 1964: one in the Hollywood Hills, one in Malibu, an office and archives on Santa Monica Boulevard in West Hollywood, California. On 15 November 2018, Hockney's 1972 work Portrait of an Artist sold at Christie's auction house in New York City for $90 million, becoming the most expensive work by a living artist sold at auction; this broke the previous record, set by the 2013 sale of Jeff Koons' Balloon Dog for $58.4 million. Hockney held this record until 15 May 2019, Jeff Koons reclaimed the honour when his Rabbit sold for more than $91 million at Christie's in New York. Hockney was born in Bradford, West Yorkshire, England, to Laura and Kenneth Hockney, the fourth of five children.

He was educated at Wellington Primary School, Bradford Grammar School, Bradford College of Art and the Royal College of Art in London, where he met R. B. Kitaj. While there, Hockney said he took pride in his work. At the Royal College of Art, Hockney featured in the exhibition Young Contemporaries – alongside Peter Blake – that announced the arrival of British Pop art, he was associated with the movement, but his early works display expressionist elements, similar to some works by Francis Bacon. When the RCA said it would not let him graduate if he did not complete an assignment of a life drawing of a female model in 1962, Hockney painted Life Painting for a Diploma in protest, he had refused to write an essay required for the final examination, saying he should be assessed on his artworks. Recognising his talent and growing reputation, the RCA changed its regulations and awarded the diploma. After leaving the RCA, he taught at Maidstone College of Art for a short time. Hockney moved to Los Angeles in 1964, where he was inspired to make a series of paintings of swimming pools in the comparatively new acrylic medium using vibrant colours.

The artist lived back and forth among Los Angeles and Paris in the late 1960s to 1970s. In 1974 he began a decade-long personal relationship with Gregory Evans who moved with him to the US in 1976 and as of 2019 remains a business partner. In 1978 he rented a house in the Hollywood Hills, bought and expanded it to include his studio, he owned a 1,643-square-foot beach house at 21039 Pacific Coast Highway in Malibu, which he sold in 1999 for around $1.5 million. Hockney has experimented with painting, printmaking, watercolours and many other media including fax machine, paper pulp, computer and iPad drawing programs; the subject matter of interest ranges from still lifes to landscapes, portraits of friends, his dogs, stage designs for the Royal Court Theatre and the Metropolitan Opera in New York City. Hockney has always returned to painting portraits throughout his career. From 1968, for the next few years, he painted portraits and double portraits of friends and relatives just under life-size in a realistic style that adroitly captured the likenesses of his subjects.

Hockney has been drawn to the same subjects – his family, artists Mo McDermott and Maurice Payne, various writers he has known, fashion designers Celia Birtwell and Ossie Clark, curator Henry Geldzahler, art dealer Nicholas Wilder, George Lawson and his ballet dancer lover, Wayne Sleep, his romantic interests throughout the years including Peter Schlesinger and Gregory Evans. More than all of these, Hockney has turned to his own figure year after year, creating over 300 self-portraits. From 1999 to 2001 Hockney used a camera lucida for his research into art history as well as his own work in the studio, he created over 200 drawings of friends and himself using this antique lens-based device. In 2016, the Royal Academy exhibited Hockney's series entitled 82 Portraits and 1 Still-life which traveled to Ca' Pesaro in Venice and the Guggenheim Museum Bilbao, in 2017 and to the Los Angeles County Museum of Art in 2018. Hockney calls the paintings started in 2013 "twenty-hour exposures" because each sitting took six to seven hours on three consecutive days.

Hockney experimented with printmaking as early as a lithograph Self-Portrait in 1954, worked in etchings during his time at RCA. In 1965, the print workshop Gemini G. E. L. Approached him to create a series of lithographs with a Los Angeles theme. Hockney responded by creating The Hollywood Collection, a series of lithographs recreating the art collection of a Hollywood star, each piece depicting an imagined work of art within a frame. Hockney went on to produce many other portfolios with Gemini G. E. L. Including Friends, The Weather Series, Some New Prints. During the 1960s he produced several series of prints he thought of as'graphic tales', including A Rake’s Progress after Hogarth, Illustrations for Fourteen Poems from C. P. Cavafy and Illustrations for Six Fairy Tales from the Brothers Grimm. In 1973 Hockney began a fruitful collaboration with Picasso's preferred printer. In his atelier he adopted Crommelynck's trademark sugar lift, as well as a system of the master's own devising of imposing a wooden frame onto the plate to ensure color separation.

Their early work together included Artist