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Gerbert of Aurillac: Astronomy and Geometry in Tenth Century Europe
October 25, 2018 15:56 WSPC/INSTRUCTION FILE Sigismondi-Gerbert International Journal of Modern Physics: Conference Series c World Scientific Publishing Company GERBERT OF AURILLAC: ASTRONOMY AND GEOMETRY IN TENTH CENTURY EUROPE COSTANTINO SIGISMONDI Sapienza University of Rome, Physics Dept., and Galileo Ferraris Institute P.le Aldo Moro 5 Roma, 00185, Italy. e-mail: [email protected] University of Nice-Sophia Antipolis - Dept. Fizeau (France); IRSOL, Istituto Ricerche Solari di Locarno (Switzerland) Received 6 Feb 2012 Revised Day Month Year Gerbert of Aurillac was the most prominent personality of the tenth century: as- tronomer, organ builder and music theoretician, mathematician, philosopher, and finally pope with the name of Silvester II (999-1003). Gerbert introduced firstly the arabic num- bers in Europe, invented an abacus for speeding the calculations and found a rational approximation for the equilateral triangle area, in the letter to Adelbold here discussed. Gerbert described a semi-sphere to Constantine of Fleury with built-in sighting tubes, used for astronomical observations. The procedure to identify the star nearest to the North celestial pole is very accurate and still in use in the XII century, when Computa- trix was the name of Polaris. For didactical purposes the Polaris would have been precise enough and much less time consuming, but here Gerbert was clearly aligning a precise equatorial mount for a fixed instrument for accurate daytime observations. Through the sighting tubes it was possible to detect equinoxes and solstices by observing the Sun in the corresponding days. The horalogium of Magdeburg was probably a big and fixed- mount nocturlabe, always pointing the star near the celestial pole. -
The Dunhuang Chinese Sky: a Comprehensive Study of the Oldest Known Star Atlas
25/02/09JAHH/v4 1 THE DUNHUANG CHINESE SKY: A COMPREHENSIVE STUDY OF THE OLDEST KNOWN STAR ATLAS JEAN-MARC BONNET-BIDAUD Commissariat à l’Energie Atomique ,Centre de Saclay, F-91191 Gif-sur-Yvette, France E-mail: [email protected] FRANÇOISE PRADERIE Observatoire de Paris, 61 Avenue de l’Observatoire, F- 75014 Paris, France E-mail: [email protected] and SUSAN WHITFIELD The British Library, 96 Euston Road, London NW1 2DB, UK E-mail: [email protected] Abstract: This paper presents an analysis of the star atlas included in the medieval Chinese manuscript (Or.8210/S.3326), discovered in 1907 by the archaeologist Aurel Stein at the Silk Road town of Dunhuang and now held in the British Library. Although partially studied by a few Chinese scholars, it has never been fully displayed and discussed in the Western world. This set of sky maps (12 hour angle maps in quasi-cylindrical projection and a circumpolar map in azimuthal projection), displaying the full sky visible from the Northern hemisphere, is up to now the oldest complete preserved star atlas from any civilisation. It is also the first known pictorial representation of the quasi-totality of the Chinese constellations. This paper describes the history of the physical object – a roll of thin paper drawn with ink. We analyse the stellar content of each map (1339 stars, 257 asterisms) and the texts associated with the maps. We establish the precision with which the maps are drawn (1.5 to 4° for the brightest stars) and examine the type of projections used. -
Chapter 3: Familiarizing Yourself with the Night Sky
Chapter 3: Familiarizing Yourself With the Night Sky Introduction People of ancient cultures viewed the sky as the inaccessible home of the gods. They observed the daily motion of the stars, and grouped them into patterns and images. They assigned stories to the stars, relating to themselves and their gods. They believed that human events and cycles were part of larger cosmic events and cycles. The night sky was part of the cycle. The steady progression of star patterns across the sky was related to the ebb and flow of the seasons, the cyclical migration of herds and hibernation of bears, the correct times to plant or harvest crops. Everywhere on Earth people watched and recorded this orderly and majestic celestial procession with writings and paintings, rock art, and rock and stone monuments or alignments. When the Great Pyramid in Egypt was constructed around 2650 BC, two shafts were built into it at an angle, running from the outside into the interior of the pyramid. The shafts coincide with the North-South passage of two stars important to the Egyptians: Thuban, the star closest to the North Pole at that time, and one of the stars of Orion’s belt. Orion was The Ishango Bone, thought to be a 20,000 year old associated with Osiris, one of the Egyptian gods of the lunar calendar underworld. The Bighorn Medicine Wheel in Wyoming, built by Plains Indians, consists of rocks in the shape of a large circle, with lines radiating from a central hub like the spokes of a bicycle wheel. -
Plotting Variable Stars on the H-R Diagram Activity
Pulsating Variable Stars and the Hertzsprung-Russell Diagram The Hertzsprung-Russell (H-R) Diagram: The H-R diagram is an important astronomical tool for understanding how stars evolve over time. Stellar evolution can not be studied by observing individual stars as most changes occur over millions and billions of years. Astrophysicists observe numerous stars at various stages in their evolutionary history to determine their changing properties and probable evolutionary tracks across the H-R diagram. The H-R diagram is a scatter graph of stars. When the absolute magnitude (MV) – intrinsic brightness – of stars is plotted against their surface temperature (stellar classification) the stars are not randomly distributed on the graph but are mostly restricted to a few well-defined regions. The stars within the same regions share a common set of characteristics. As the physical characteristics of a star change over its evolutionary history, its position on the H-R diagram The H-R Diagram changes also – so the H-R diagram can also be thought of as a graphical plot of stellar evolution. From the location of a star on the diagram, its luminosity, spectral type, color, temperature, mass, age, chemical composition and evolutionary history are known. Most stars are classified by surface temperature (spectral type) from hottest to coolest as follows: O B A F G K M. These categories are further subdivided into subclasses from hottest (0) to coolest (9). The hottest B stars are B0 and the coolest are B9, followed by spectral type A0. Each major spectral classification is characterized by its own unique spectra. -
Dhruva the Ancient Indian Pole Star: Fixity, Rotation and Movement
Indian Journal of History of Science, 46.1 (2011) 23-39 DHRUVA THE ANCIENT INDIAN POLE STAR: FIXITY, ROTATION AND MOVEMENT R N IYENGAR* (Received 1 February 2010; revised 24 January 2011) Ancient historical layers of Hindu astronomy are explored in this paper with the help of the Purân.as and the Vedic texts. It is found that Dhruva as described in the Brahmân.d.a and the Vis.n.u purân.a was a star located at the tail of a celestial animal figure known as the Úiúumâra or the Dolphin. This constellation, which can be easily recognized as the modern Draco, is described vividly and accurately in the ancient texts. The body parts of the animal figure are made of fourteen stars, the last four of which including Dhruva on the tail are said to never set. The Taittirîya Âran.yaka text of the Kr.s.n.a-yajurveda school which is more ancient than the above Purân.as describes this constellation by the same name and lists fourteen stars the last among them being named Abhaya, equated with Dhruva, at the tail end of the figure. The accented Vedic text Ekâgni-kân.d.a of the same school recommends observation of Dhruva the fixed Pole Star during marriages. The above Vedic texts are more ancient than the Gr.hya-sûtra literature which was the basis for indologists to deny the existence of a fixed North Star during the Vedic period. However the various Purân.ic and Vedic textual evidence studied here for the first time, leads to the conclusion that in India for the Yajurvedic people Thuban (α-Draconis) was Dhruva the Pole Star c 2800 BC. -
The RHN Bulletin October-07
THE BULLETIN October 2007 No. 466 2005-2006 EXECUTIVE President Marianne Yake . 905-883-3047 Events calendar [email protected] Past President Natalie Helferty Botany Group Meeting Monday November 5, 2007. 12:30pm & Speakers [email protected] 2nd Vice President -- Position Available -- Executive Meeting Tuesday November 13, 2007. 7:30pm Secretary -- Position Available -- Where: Robert Holland Centre Treasurer Gene Denzel [email protected] Bird Goup Meeting Wednesday November 14, 2007. 7:30pm th 50 Anniversary Michael White Topic: Vesper Sparrow and Field Sparrow Field Trips Tom Waechter Host: Theo Hofmann, 199 Arnold Av. Thornhill [email protected] Environment -- Position Available -- General Meeting Thursday November 15, 2007. 7:30pm Publicity Nancy Zalman [email protected] Joint meeting with West Humber Naturalists Bulletin Editor Lloyd Helferty . 905-707-8754 Speaker: Anne Parker [email protected] Topic: An Inconvenient Truth–Climate Change Membership Mike Turk Location: Richmond Hill Presbyterian Church, [email protected] Wallace Hall. 10066 Yonge St. Events -- Position Available – Ontario Nature Rep Diana Piché -- Reminder: There is NO meeting in December -- Website coordinator Rod Potter [email protected] Check for more Events and Outings on Page 2 Gladys McLatchy Fall is always welcomed to the Richmond Hill Naturalists members and friends. It is a time to embark on work and play and set out the future for our membership. Our annual corn roast has been hosted for 44 years at Russell Tilt’s home, and we greatly acknowledge the work he has done for our club and the community. We were able to enjoy and catch up with each other after our summer. -
The Dawn of a New Era in Richmond Hill
WWW.BENCHMARKSIGNATUREREALTY.COM THE DAWN OF A NEW ERA IN RICHMOND HILL A new Era in sophisticated urban living is coming to Yonge Street. Inspired by the culture, energy and dynamism of its iconic setting, Era will redefine condominium living in the heart of Richmond Hill. WWW.BENCHMARKSIGNATUREREALTY.COM Experience the Yonge Street lifestyle in a whole new light – the arts, the culture, the shopping and dining, parks and recreation. Pemberton Group proudly introduces a whole new way of thinking and living in the heart of Richmond Hill. Welcome to Era Condominiums, the dawn of a new era in sophisticated urban living. Two soaring towers rise over a majestic podium, overlooking spectacular views of the neighbourhood. Era is part of Pemberton’s iconic master-planned community at Yonge Street and Highway 7, just steps from everything you love. WWW.BENCHMARKSIGNATUREREALTY.COM Brilliantly landscaped grounds encircle the community, with a beautiful courtyard garden, tranquil walkways and verdant greenspace. A winding porte cochère driveway brings you to the covered entrance, and into the magnificent lobby. Modern, comfortable, refined. Welcome home. WWW.BENCHMARKSIGNATUREREALTY.COM LOBBY 2 4 1 6 7 8 3 9 5 10 1. Landscaped Garden 6. Outdoor Terrace & BBQ 2. Yoga Studio 7. Outdoor Lounge 3. Fitness Centre 8. Games Room 4. Party Room 9. Men’s Washroom & Steam Room 5. Pool 10. Women’s Washroom & Steam Room WWW.BENCHMARKSIGNATUREREALTY.COM AMENITY PLAN It’s about celebrating the good times, enriching the body and soul, and experiencing the finer things in life. Era offers you a spectacular roster of indoor and outdoor lifestyle amenities designed to let you live life to the fullest. -
Meeting #4/11
INDEX TO AUTHORITY MEETING #4/11 Friday, April 29, 2011 MINUTES Minutes of Meeting #3/11, held on March 25, 2011 137 PRESENTATIONS Gee, Jon, Manager, Great Lakes Area of Concern, Environment Canada re: Toronto and Region Remedial Action Plan 137 Farrell, Laurian, Manager, Flood Risk Management and Infrastructure, TRCA re: Flood Management Service 137 Dillane, Jim, Director, Finance and Business Services, TRCA re: 2011 Operating and Capital Budget 137 CORRESPONDENCE Kunzle, Santiage, Principal, Montgomery Sisam Architects Inc. re: Royal Architectural Institute of Canada Firm of the Year Award 137 TORONTO AND REGION REMEDIAL ACTION PLAN 141 FUTURE FORESTS Silvicultural Forest Pests Status Report 143 WEST NILE VIRUS PROGRAM ANNUAL REPORT West Nile Virus Vector Mosquito Larval Monitoring and Surveillance - 2010 and Five Year Data Summary 148 REGIONAL WATERSHED MONITORING PROGRAM Annual Report of Activity 154 GLEN STEWART RAVINE MASTER PLAN IMPLEMENTATION 161 TORONTO HISTORICAL PARK Node Construction and Signage Installation 164 BOB HUNTER MEMORIAL PARK Extension of Contract with Friends of the Rouge Valley for Forest Planting 165 GREAT LAKES AND MISSISSIPPI RIVER INTERBASIN FEASIBILITY STUDY Invasive Asian Carp Species 169 ONTARIO NATURE'S 20/20 VISION 171 COMMUNITY PROGRAM FOR STORMWATER MANAGEMENT 174 GREENLANDS ACQUISITION PROJECT FOR 2011-2015 Flood Plain and Conservation Component, Humber River Watershed Susan Punter and Christine Bell 176 GREENLANDS ACQUISITION PROJECT FOR 2011-2015 Flood Plain and Conservation Component, Petticoat -
JRASC August 2021 Lo-Res
The Journal of The Royal Astronomical Society of Canada PROMOTING ASTRONOMY IN CANADA August/août 2021 Volume/volume 115 Le Journal de la Société royale d’astronomie du Canada Number/numéro 4 [809] Inside this issue: A Pas de Deux with Aurora and Steve Detection Threshold of Noctilucent Clouds The Sun, Moon, Waves, and Cityscape The Best of Monochrome Colour Special colour edition. This great series of images was taken by Raymond Kwong from his balcony in Toronto. He used a Canon EOS 500D, with a Sigma 70–300 ƒ/4–5.6 Macro Super lens (shot at 300 mm), a Kenko Teleplus HD 2× DGX teleconverter and a Thousand Oaks solar filter. The series of photos was shot at ISO 100, 0.1s, 600 mm at ƒ/11. August/ août 2021 | Vol. 115, No. 4 | Whole Number 809 contents / table des matières Feature Articles / Articles de fond 182 Binary Universe: Watch the Planets Wheel Overhead 152 A Pas de Deux with Aurora and Steve by Blake Nancarrow by Jay and Judy Anderson 184 Dish on the Cosmos: FYSTing on a 160 Detection Threshold of Noctilucent Clouds New Opportunity and its Effect on Season Sighting Totals by Erik Rosolowsky by Mark Zalcik 186 John Percy’s Universe: Everything Spins 166 Pen and Pixel: June 10 Partial Eclipse (all) by John R. Percy by Nicole Mortillaro / Allendria Brunjes / Shelly Jackson / Randy Attwood Departments / Départements Columns / Rubriques 146 President’s Corner by Robyn Foret 168 Your Monthly Guide to Variable Stars by Jim Fox, AAVSO 147 News Notes / En manchettes Compiled by Jay Anderson 170 Skyward: Faint Fuzzies and Gravity by David Levy 159 Great Images by Michael Gatto 172 Astronomical Art & Artifact: Exploring the History of Colonialism and Astronomy in 188 Astrocryptic and Previous Answers Canada II: The Cases of the Slave-Owning by Curt Nason Astronomer and the Black Astronomer Knighted by Queen Victoria iii Great Images by Randall Rosenfeld by Carl Jorgensen 179 CFHT Chronicles: Times They Are A-Changing by Mary Beth Laychak Bleary-eyed astronomers across most of the country woke up early to catch what they could of the June 10 annular eclipse. -
WALLABY – an SKA Pathfinder H I Survey
University of Louisville ThinkIR: The University of Louisville's Institutional Repository Faculty Scholarship 7-1-2020 WALLABY – an SKA Pathfinder H i survey Bärbel S. Koribalski Australia Telescope National Facility L. Staveley-Smith ARC Centre of Excellence for All-sky Astrophysics T. Westmeier ARC Centre of Excellence for All-sky Astrophysics P. Serra Osservatorio Astronomico di Cagliari K. Spekkens Royal Military College of Canada See next page for additional authors Follow this and additional works at: https://ir.library.louisville.edu/faculty Part of the Astrophysics and Astronomy Commons ThinkIR Citation Koribalski, Bärbel S.; Staveley-Smith, L.; Westmeier, T.; Serra, P.; Spekkens, K.; Wong, O. I.; Lee-Waddell, K.; Lagos, C. D.P.; Obreschkow, D.; Ryan-Weber, E. V.; Zwaan, M.; Kilborn, V.; Bekiaris, G.; Bekki, K.; Bigiel, F.; Boselli, A.; Bosma, A.; Catinella, B.; Chauhan, G.; Cluver, M. E.; Colless, M.; Courtois, H. M.; Crain, R. A.; de Blok, W. J.G.; Dénes, H.; Duffy, A. R.; Elagali, A.; Fluke, C. J.; For, B. Q.; Heald, G.; Henning, P. A.; Hess, K. M.; and Holwerda, Benne W., "WALLABY – an SKA Pathfinder H i survey" (2020). Faculty Scholarship. 476. https://ir.library.louisville.edu/faculty/476 This Article is brought to you for free and open access by ThinkIR: The University of Louisville's Institutional Repository. It has been accepted for inclusion in Faculty Scholarship by an authorized administrator of ThinkIR: The University of Louisville's Institutional Repository. For more information, please contact [email protected]. Authors Bärbel S. Koribalski, L. Staveley-Smith, T. Westmeier, P. Serra, K. Spekkens, O. -
The Unveiling of the Newly Discovered Vela Supercluster 1
The Unveiling of the newly discovered Vela Supercluster ∗ PoS(SSC2015)040 Renée C. Kraan-Korteweg†, Thomas H. Jarrett and Ahmed Elagali Astrophysics, Cosmology and Gravity Centre, University of Cape Town, 7701 Rondebosch, South Africa E-mail: [email protected] Michelle E. Cluver Department of Physics, University of the Western Cape, Bellville, South Africa Maciej Bilicki Astrophysics, Cosmology and Gravity Centre, University of Cape Town, 7701 Rondebosch, South Africa & Leiden Observatory, Leiden University, The Netherlands Matthew M. Colless Research School of Astronomy and Astrophysics, Australian National University, Canberra, Australia Multi-object spectroscopic observations of high density galaxy concentrations were obtained be- tween 2012 and 2014 with SALT, using the multi-object spectrometer (MOS) of the Robert Stobie Spectograph (RSS) on SALT. The goal was to find the missing clusters in an earlier identified ex- tended galaxy overdensity centered at ∼ 18000 km s−1 located at low Galactic latitudes in Vela. Reliable redshifts could be extracted for ∼ 80% of the targeted, highly-obscured galaxies. They were found to have an accuracy of the order of s ∼ 150 km s−1. Of the 13 observed fields, ten revealed clear signatures of galaxy clusters. The majority of the clusters form part of the Vela overdensity. Their distribution also confirmed our suspicion that the Vela overdensity is even more extended and seems to straddle the Galactic Plane. Subsequent multi-fibre spectroscopy with AAOmega+2dF on the Australian Telescope confirmed that these clusters are embedded in a gigantic overdensity of about 20◦ ×20◦ on the sky. The overdensity and its clusters show strong similarities to massive superclusters such as the Shapley Supercluster. -
Annual Report / Rapport Annuel / Jahresbericht 1996
Annual Report / Rapport annuel / Jahresbericht 1996 ✦ ✦ ✦ E U R O P E A N S O U T H E R N O B S E R V A T O R Y ES O✦ 99 COVER COUVERTURE UMSCHLAG Beta Pictoris, as observed in scattered light Beta Pictoris, observée en lumière diffusée Beta Pictoris, im Streulicht bei 1,25 µm (J- at 1.25 microns (J band) with the ESO à 1,25 microns (bande J) avec le système Band) beobachtet mit dem adaptiven opti- ADONIS adaptive optics system at the 3.6-m d’optique adaptative de l’ESO, ADONIS, au schen System ADONIS am ESO-3,6-m-Tele- telescope and the Observatoire de Grenoble télescope de 3,60 m et le coronographe de skop und dem Koronographen des Obser- coronograph. l’observatoire de Grenoble. vatoriums von Grenoble. The combination of high angular resolution La combinaison de haute résolution angu- Die Kombination von hoher Winkelauflö- (0.12 arcsec) and high dynamical range laire (0,12 arcsec) et de gamme dynamique sung (0,12 Bogensekunden) und hohem dy- (105) allows to image the disk to only 24 AU élevée (105) permet de reproduire le disque namischen Bereich (105) erlaubt es, die from the star. Inside 50 AU, the main plane jusqu’à seulement 24 UA de l’étoile. A Scheibe bis zu einem Abstand von nur 24 AE of the disk is inclined with respect to the l’intérieur de 50 UA, le plan principal du vom Stern abzubilden. Innerhalb von 50 AE outer part. Observers: J.-L. Beuzit, A.-M.