SUMMARY / RELATED TOPICS

Abū Ishāq Ibrāhīm al-Zarqālī

Abū Isḥāq Ibrāhīm ibn Yaḥyā al-Naqqāsh al-Zarqālī al-Tujibi. Although his name is conventionally given as al-Zarqālī, it is probable that the correct form was al-Zarqālluh. In Latin he was referred to as Arzachel or Arsechieles, a modified form of Arzachel, meaning'the engraver', he lived in Toledo, Al-Andalus before moving to Córdoba in his life. His works inspired a generation of Islamic astronomers in Al-Andalus, after being translated, were influential in Europe, his invention of the Saphaea proved popular and was used by navigators until the 16th century. The crater Arzachel on the Moon is named after him. Al-Zarqālī was born in a village near the outskirts of Toledo, the capital of the Taifa of Toledo, he was trained as a metalsmith and due to his burr skills he was nicknamed Al-Nekkach "the engraver of metals". His Latinized name,'Arzachel' is formed from the Arabic al-Zarqali al-Naqqash, meaning'the engraver', he was talented in Geometry and Astronomy. He is known to have taught and visited Córdoba on various occasions, his extensive experience and knowledge made him the foremost astronomer of his time.

Al-Zarqālī was an inventor, his works helped to put Toledo at the intellectual center of Al-Andalus. He is referred to in the works of Chaucer, as'Arsechieles'. In the year 1085 Toledo was taken by the Christian king of Castile Alfonso VI. Al-Zarqālī and his colleagues, such as Al‐Waqqashi of Toledo, had to flee, it is unknown whether the aged Al-Zarqālī died in a Moorish refugee camp. His works influenced Ibn Bajjah, Ibn Tufail, Ibn Rushd, Ibn al-Kammad, Ibn al‐Haim al‐Ishbili and Nur ad-Din al-Betrugi. In the 12th century, Gerard of Cremona translated al-Zarqali’s works into Latin, he referred to Al-Zarqali as an magician. Ragio Montanous wrote a book in the 15th century on the advantages of the Sahifah al-Zarqalia. In 1530, the German scholar Jacob Ziegler wrote a commentary on one of al-Zarqali’s works. In his "De Revolutionibus Orbium Coelestium", in the year 1530, Nicolaus Copernicus quotes the works of al-Zarqali and Al-Battani. Al-Zarqālī wrote two works on the construction of an instrument for computing the position of the planets using diagrams of the Ptolemaic model.

These works were translated into Spanish in the 13th century by order of King Alfonso X in a section of the Libros del Saber de Astronomia entitled the "Libros de las laminas de los vii planetas". He invented a perfected kind of astrolabe known as "the tablet of al-Zarqālī", famous in Europe under the name Saphaea. There is a record of an al-Zarqālī who built a water clock, capable of determining the hours of the day and night and indicating the days of the lunar months. According to a report found in al-Zuhrī's Kitāb al-Juʿrāfīyya, his name is given as Abū al-Qāsim bin ʿAbd al-Raḥmān known as al-Zarqālī, which has made some historians think that this is a different person. Al-Zarqali corrected geographical data from Al-Khwarizmi, he corrected Ptolemy’s estimate of the longitude of the Mediterranean Sea from 62 degrees to the correct value of 42 degrees. In his treatise on the solar year, which survives only in a Hebrew translation, he was the first to demonstrate the motion of the solar apogee relative to the fixed background of the stars.

He measured its rate of motion as 12.04 seconds per year, remarkably close to the modern calculation of 11.77 seconds. Al-Zarqālī's model for the motion of the Sun, in which the center of the Sun's deferent moved on a small rotating circle to reproduce the observed motion of the solar apogee, was discussed in the thirteenth century by Bernard of Verdun and in the fifteenth century by Regiomontanus and Peurbach. In the sixteenth century Copernicus employed this model, modified to heliocentric form, in his De Revolutionibus Orbium Coelestium. Al-Zarqālī contributed to the famous Tables of Toledo, an adaptation of earlier astronomical data to the location of Toledo along with the addition of some new material. Al-Zarqālī was famous as well for his own Book of Tables. Many "books of tables" had been compiled, but his almanac contained tables which allowed one to find the days on which the Coptic, Roman and Persian months begin, other tables which give the position of planets at any given time, still others facilitating the prediction of solar and lunar eclipses.

He compiled an almanac that directly provided "the positions of the celestial bodies and need no further computation". The work provided the true daily positions of the sun for four Julian years from 1088 to 1092, the true positions of the five planets every 5 or 10 days over a period of 8 years for Venus, 79 years for Mars, so forth, as well as other related tables, his Zij and Almanac were translated into Latin by Gerard of Cremona in the 12th century, contributed to the rebirth of a mathematically based astronomy in Christian Europe and were incorporated into the Tables of Toledo in the 12th century and the Alfonsine tables in the 13th century. In designing an instrument to deal with Ptolemy's complex model for the planet Mercury, in which the center of the deferent moves on a secondary epicycle, al-Zarqālī noted that the path of the center of the primary epicycle is not a circle, as it is for the other planets. Instead it is oval and similar to the shape of a pignon; some writers have misinterpreted al-Zarqālī's description of an earth-cente

Laurent Romejko

Laurent Francis Gabriel Romejko is a French television host. Romejko was born in Yvelines. After being a taxicab driver for a while, he was a graduate of the Ecole Supérieure de Journalisme de Paris, he began by presenting the Minitel of Enfants du rock on Antenne 2 before going on radio. He joined Télématin in 1989, he presented the weather. In 1991, he presented the magazine Cajou on Canal Selecto on Paris Première. On Télématin, he replaced William Leymergie. From 1994 to 1999, he presented the weather each morning on RFM. In 2000, he participated in the launch of channel Santé-Vie and hosted a magazine devoted to health professionals. In September 2006, he presented the weather on France 2, he hosts Des chiffres et des lettres daily on France 2. On September 2006, the program moved to France 3, but Romejko continued to present it, alongside Arielle Boulin-Prat and Bertrand Renard. "Laurent Romejko, le Monsieur Météo"

2017 VR12

2017 VR12 is a sub-kilometer asteroid with a somewhat elongated and angular shape 160 meters in diameter. It is classified as near-Earth object and hazardous asteroid of the Apollo or Amor group; the V-type asteroid has a rotation period of 1.5 hours. It was first observed on 10 November 2017 by the 60-inch Pan-STARRS 1 telescope at Haleakala Observatory in Hawaii, it orbits the Sun at a distance of 1.0 -- 1.7 AU once 7 months. Its orbit has an inclination of 9 ° with respect to the ecliptic. 2017 VR12 is a V-type asteroid with a bright surface. 2017 VR12 passed 0.0097 AU from Earth on 7 March 2018, the closest approach by this asteroid known. It brightened to 12th magnitude, it was observed by radar from Green Bank and Arecibo Observatory. Images revealed that 2017 VR12 is a elongated and angular body with a size of 160 by 100 meters. Images obtained at Green Bank and Arecibo observatories in 2018, revealed that 2017 VR12 is a elongated and angular body with a size of 160 by 100 meters. On 5 March 2018, a rotational lightcurve was obtained from photometric observations by astronomers at the Northolt Branch Observatories.

Lightcurve analysis gave a rotation period of 1.5 hours with a brightness amplitude between 0.4 and 0.5 magnitude. Asteroid Lightcurve Database, query form Dictionary of Minor Planet Names, Google books Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend Discovery Circumstances: Numbered Minor Planets - – Minor Planet Center 2017 VR12: Asteroid That Could Be Bigger Than Empire State Building Is About to Pass by Earth 3/2/2018 2017 VR12 at the JPL Small-Body Database Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters