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Variable Star Section Circular
ΒΑΛ The British Astronomical Association VARIABLE STAR SECTION CIRCULAR 64 "LIGHT-CURVE” AUGUST 1986 ISSN 0267-9272 Office: Burlington House, Piccadilly, London, W1V 9AG SECTION OFFICERS: Director D.R.B. Saw, 'Upanova1, 18 Dolllcott, Haddenham, Aylesbury, Bucks. HP17 8JG Tel: Haddenham (0844) 292065 Assistant Director S.R. Dunlop, 140 Stocks Lane, East Wittering, nr Chichester, West Sussex P020 8NT Tel: Bracklesham Bay (0243) 670354 Secretary M.D. Taylor, 17 Cross Lane, Wakefield, West Yorkshire WF2 8DA Tel: Wakefield (0924) 374651 Programme Secretaries: Assistant Secretary (Post temporarily vacant) Telescopic Assistant Secretary J. Toone, 2 Hilton Crescent, Boothstown, Binocular Worsley, Manchester M28 4FY Tel: 061 702 8619 Eclipsing Binary J.E. Isles, Rose Cottage, 22 High Street, Secretary Wescott, Bucks. HP18 OPU Tel: Aylesbury (0296) 651779 Nova/Supernova G.M Hurst, 16 Westminster Close, Search Secretary Kempshott Rise, Basingstoke, Hants. RG22 4PP Tel: Basingstoke (0256) 471074 Chart Secretary J. Parkinson, 229 Scar Lane, Golcar, (except Eclipsing) Huddersfield, West Yorkshire HD7 4AU Tel: Huddersfield (0484) 642947 For subcription rates and charges for charts and other publications see inside back cover. Editorial It has been suggested that these C irc u la rs are often a little 'dry' and technical for some members. We are always happy to receive more 'personal' items and hope to include more in future issues. We are also including an occasional short note on some of the terms encountered, and which may not be fully explained in some of the specific articles. The first such item appears on p.13. If you have any queries, however elementary, please send them in, and we shall do our best to provide the answers. -
Variable Star
Variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) fluctuates. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either: Intrinsic variables, whose luminosity actually changes; for example, because the star periodically swells and shrinks. Extrinsic variables, whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star has an orbiting companion that sometimes Trifid Nebula contains Cepheid variable stars eclipses it. Many, possibly most, stars have at least some variation in luminosity: the energy output of our Sun, for example, varies by about 0.1% over an 11-year solar cycle.[1] Contents Discovery Detecting variability Variable star observations Interpretation of observations Nomenclature Classification Intrinsic variable stars Pulsating variable stars Eruptive variable stars Cataclysmic or explosive variable stars Extrinsic variable stars Rotating variable stars Eclipsing binaries Planetary transits See also References External links Discovery An ancient Egyptian calendar of lucky and unlucky days composed some 3,200 years ago may be the oldest preserved historical document of the discovery of a variable star, the eclipsing binary Algol.[2][3][4] Of the modern astronomers, the first variable star was identified in 1638 when Johannes Holwarda noticed that Omicron Ceti (later named Mira) pulsated in a cycle taking 11 months; the star had previously been described as a nova by David Fabricius in 1596. This discovery, combined with supernovae observed in 1572 and 1604, proved that the starry sky was not eternally invariable as Aristotle and other ancient philosophers had taught. -
Binocular Universe: Hail the Queen November 2010
Binocular Universe: Hail the Queen November 2010 Phil Harrington hope you're dressed appropriately, because this month we have an audience with the Queen…Queen Cassiopeia, that is. Cassiopeia reigns over the autumn I sky as she rides high in the north, sitting on her royal throne. You have probably heard the story of Queen Cassiopeia, of how she and King Cepheus ruled ancient Ethiopia. Cassiopeia was well known for two things: her great beauty and her shameless arrogance. One day, she bragged of being more beautiful than the sea nymphs, who were well-known for their exquisite loveliness. Above: Autumn star map from Star Watch by Phil Harrington Above: Finder chart for this month's Binocular Universe. Chart adapted from Touring the Universe through Binoculars Atlas (TUBA), www.philharrington.net/tuba.htm The sea nymphs overheard this boasting and complained to their father, Poseidon, the king of the seas. Poseidon became so infuriated that he created Cetus the Sea Monster. Cetus was sent to Ethiopia to devour the citizens of the land. King Cepheus was told that his people could be saved only if he were to sacrifice his daughter Andromeda to the sea monster. As king, he had no alternative but to lead his daughter to the water's edge and chain her to a rock. There, she was left to the mercy of Cetus. Just then, our hero, Perseus, appeared on the scene. Perseus, the son of Zeus, had been ordered to kill a gorgon called Medusa. Medusa was a very ugly creature whose hair was made of snakes. -
Reading Hypermedia Narrative Stars, 88 Constellations for Wittgenstein by David Clark
Artigo Original http://dx.doi.org/10.5007/1807-9288.2015v11n1p287 READING HYPERMEDIA NARRATIVE STARS, 88 CONSTELLATIONS FOR WITTGENSTEIN BY DAVID CLARK. ANALYTICAL APPROACH TO CONSTELLATION 18 CASSIOPEIA Nohelia Meza* ABSTRACT: This article presents an approach to analyze hypermedia discourse elements found in Cassiopeia, one of the constellations that compose 88 Constellations for Wittgenstein (To Be Played with the Left Hand) (2011) by net.art artist David Clark. Even though there are many approaches to the subject of electronic literature, there are still many unexplored e-lit works waiting to be studied that undoubtedly will raise questions about the literariness of electronic literature. This article briefly outlines issues of representation, temporality, semiotics, interaction, and manipulation on this specific constellation of the aforementioned e-lit work. Specific new media literary theories (temporal possibilities in programmed texts; temporal levels for cybertexts with narrative content; pluricode couplings, lability of digital works) have been applied to the selected corpus in order to examine the nuances and gradations of electronic textuality and literary reception. The analysis shows that the user‘s manipulation and interaction with the e-lit work affect certain elements in the hypermedia narrative discourse so as to suggest new possibilities of temporal and semiotic interpretation. KEYWORDS: Discourse Analysis. Electronic Literature. Narrativity. Semiotics. Temporality. Introduction In this article, I present an analytical -
Variations of Gamma Cassiopeiae
PB 151380 ^0.21 jBoulder laboratories VARIATIONS OF GAMMA CASSIOPEIAE BY S. R. POTTASCH U. S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS National Bureau of Standards SEP 2 1 1960 THE NATIONAL BUREAU OF STANDARDS Functions and Activities The functions of the National Bureau of Standards are set forth in the Act of Congress, March 3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and maintenance of the national standards of measurement and the provision of means and methods for making measurements consistent with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials, devices, and structures; advisory services to government agencies on scientific and technical problems; in- vention and development of devices to serve special needs of the Government; and the development of standard practices, codes, and specifications. The work includes basic and applied research, development, engineering, instrumentation, testing, evaluation, calibration services, and various consultation and information services. Research projects are also performed for other government agencies when the work relates to and supplements the basic program of the Bureau or when the Bureau's unique competence is required. The scope of activities is suggested by the listing of divisions and sections on the inside of the back cover. Publications The results of the Bureau's work take the form of either actual equipment and devices or pub- -
Astronomical League Bright Nebula List Cross-Referenced with Lynds Catalog to Include LBN # and Lynds Brightness Estimage (Lb)
Astronomical League Bright Nebula List Cross-Referenced with Lynds Catalog to Include LBN # and Lynds brightness estimage (Lb) (Some corrections have been made—see comments following table) # Primary ID Other name Common name LBN # Type Con RA Dec Size Lb 1 NGC 281 IC 1590 Pac Man 616 E CAS 00 52.8 +56 36 30 1 2 LBN 619 619 E AND 00 53.4 +34 35 110 6 3 Sh 2-183 E CAS 00 53.5 +65 42 45 IC 59 620 2 4 Sh 2-185 Gamma Cassiopeiae C CAS 00 56.7 +61 04 40 IC 63 622 1 5 NGC 896 IC 1795 645 E CAS 02 25.5 +62 01 13 1 IC 1795 645 1 6 Melotte 15 Heart E CAS 02 33.4 +61 26 100 IC 1805 654 3 7 IC 1848 Soul 667 E CAS 02 50.5 +60 17 40 2 8 vdB 14 BD+59 660 R CAM 03 29.0 +59 63 46 9 NGC 1333 Embryo 741 R PER 03 29.3 +31 25 9 3 10 vdB 15 BD+58 607 R CAM 03 29.5 +58 52 54 11 GK-N1901 MCG+7-8-22 Nova Persei 1901 S PER 03 31.1 +43 54 1 12 DG 19 721 R PER 03 35.1 +38 00 12 5 13 IC 348 LBN 758 758 R PER 03 44.6 +32 10 10 2 14 vdB 20 Electra R TAU 03 44.9 +24 07 20 15 vdB 21 BD+23 516 Maia R TAU 03 45.4 +24 22 52 16 vdB 22 BD+23 522 Merope R TAU 03 46.1 +23 56 52 17 vdB 23 BD+23 541 Alcyone R TAU 03 47.2 +24 06 34 18 IC 353 E TAU 03 55.0 +25 29 180 19 NGC 1499 California 756 E PER 04 00.7 +36 37 150 1 20 NGC 1491 Fossil Footprint 704 E PER 04 02.9 +51 17 3 1 21 IC 360 LBN 786 786 E TAU 04 13.0 +25 38 180 4 NGC 1554 Hind’s Lost 22 Sh 2-238 817 R TAU 04 21.8 +19 32 1 2 NGC 1555 Struve’s Variable 23 LBN 896 896 E ERI 04 27.2 -06 13 40 5 24 Sh 2-210 712 E PER 04 30.5 +52 33 20 5 25 NGC 1579 Northern Trifid 767 R PER 04 30.7 +35 15 12 4 26 NGC 1624 722 E PER 04 40.0 -
The COLOUR of CREATION Observing and Astrophotography Targets “At a Glance” Guide
The COLOUR of CREATION observing and astrophotography targets “at a glance” guide. (Naked eye, binoculars, small and “monster” scopes) Dear fellow amateur astronomer. Please note - this is a work in progress – compiled from several sources - and undoubtedly WILL contain inaccuracies. It would therefor be HIGHLY appreciated if readers would be so kind as to forward ANY corrections and/ or additions (as the document is still obviously incomplete) to: [email protected]. The document will be updated/ revised/ expanded* on a regular basis, replacing the existing document on the ASSA Pretoria website, as well as on the website: coloursofcreation.co.za . This is by no means intended to be a complete nor an exhaustive listing, but rather an “at a glance guide” (2nd column), that will hopefully assist in choosing or eliminating certain objects in a specific constellation for further research, to determine suitability for observation or astrophotography. There is NO copy right - download at will. Warm regards. JohanM. *Edition 1: June 2016 (“Pre-Karoo Star Party version”). “To me, one of the wonders and lures of astronomy is observing a galaxy… realizing you are detecting ancient photons, emitted by billions of stars, reduced to a magnitude below naked eye detection…lying at a distance beyond comprehension...” ASSA 100. (Auke Slotegraaf). Messier objects. Apparent size: degrees, arc minutes, arc seconds. Interesting info. AKA’s. Emphasis, correction. Coordinates, location. Stars, star groups, etc. Variable stars. Double stars. (Only a small number included. “Colourful Ds. descriptions” taken from the book by Sissy Haas). Carbon star. C Asterisma. (Including many “Streicher” objects, taken from Asterism. -
Gamma Cassiopeiae and HR 266: a Massive Septuplet Illuminating the IC 59 and IC 63 Nebulae at D = 168 Pc
Vol. 13 No. 2 April 1, 2017 Journal of Double Star Observations Page 264 Gamma Cassiopeiae and HR 266: A Massive Septuplet Illuminating the IC 59 and IC 63 Nebulae at d = 168 pc Eric Mamajek Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA University of Rochester, Rochester, NY Abstract: The unusual prototype Be shell star γ Cas is part of a triple system (WDS J00567+6043) that illuminates two arc-shaped nebulae: IC 59 and IC 63. The HR 266 system (WDS J00568+6022) is a massive quadruple lying 1274” away from γ Cas (projected separation 1.0 pc), opposite of the reflection nebulae, which appears to be physically associated with this system based on common proper motion, radial velocity, and parallax. The entire γ Cas system appears to constitute a massive septuplet (at least), with approximately 15 MSun in mass associ- ated with the γ Cas triplet, and about 13.5 MSun in mass associated with the HR 266 quadruplet. The γ Cas system appears to be one of the highest multiplicity systems known (N=7). 1 Introduction: primary Aa is a B0.5IVe with mass ~13 MSun , and the γ Cas (HR 264, HIP 4427, ADS 782, 2MASS secondary Ab has a mass of approximately 1.0 MSun J00564251+6043002) is a famous eruptive Be shell (Nemravova, et al. 2012). The primary Aa itself has a star, which has shown irregular brightness variations 1.1 day photometric periodicity which has been at- since its discovery as the first Be star by Secchi (1867; tributed to a close-in white dwarf companion (Apparao see historical discussion by Harmanec, et al. -
The X-Ray Emission of the Γ Cassiopeiae Stars
The X-ray emission of the γ Cassiopeiae stars Myron A. Smith National Optical Astronomical Observatory, 950 N. Cherry Ave., Tucson, AZ, U.S.A. R. Lopes de Oliveira Universidade Federal de Sergipe, Departamento de F´ısica, Av. Marechal Rondon, S/N, 49000-000 S˜ao Crist´ov˜ao, SE, Brazil; Observat´orio Nacional, Rua Gal. Jos´eCristino 77, 20921-400, Rio de Janeiro, RJ, Brazil C. Motch Observatoire Astronomique, Universit´ede Strasbourg, CNRS UMR7550, 11 rue de l’Universit´e, F-67000, Strasbourg, France Abstract Long considered as the “odd man out” among X-ray emitting Be stars, γ Cas (B0.5e IV) is now recognized as the prototype of a class of stars that emit hard thermal X-rays. Our classification differs from the historical use of the term “γ Cas stars” defined from optical properties alone. The luminosity output of this class contributes significantly to the hard X-ray production in massive stars in the Galaxy. The γ Cas stars have light curves showing variability on a few broadly-defined timescales and spectra indicative of an optically thin plasma consisting of one or more hot thermal components. By now 9–13 Galactic ≈B0-1.5e main sequence stars are judged to be mem- bers or candidate members of the γ Cas class. Conservative criteria for this designation are for a ≈B0-1.5e III-V star to have an X-ray luminosity of 1032– 1033 ergs s−1, a hot thermal spectrum containing the short wavelength Lyα arXiv:1512.06446v3 [astro-ph.SR] 20 Jan 2016 Fe XXV and Fe XXVI lines and the fluorescence FeK feature all in emission. -
CONSTELLATION CASSIOPEIA Named After the Queen of Aethiopia
CONSTELLATION CASSIOPEIA named after the queen of Aethiopia. Cassiopeia was the wife of Cepheus, King of Aethiopia and mother of Princess Andromeda. It is a constellation in the northern sky and one of the 48 constellations listed by the 2nd-century Greek astronomer Ptolemy, and remains one of the 88 modern constellations today. It is easily recognizable due to its distinctive 'W' shape formed by five bright stars. It is bordered by Andromeda to the south, Perseus to the southeast, and Cepheus to the north. It is opposite the Big Dipper. In northern locations it is visible year-round and it can be seen even in low southern latitudes low in the North. THE STARS The four brightest stars of Cassiopeia are all brighter than the third magnitude. • Alpha Cassiopeiae, traditionally called Shedir (from the Arabic Al Sadr, "the breast"), is a double star. The primary is an orange giant of magnitude 2.2, 229 light-years from Earth. • Beta Cassiopeiae, or Caph (meaning "hand"), is a white-hued star of magnitude 2.3, 54 light-years from Earth. 16th-century Arabian astronomer Al Tizini gave this star the name Al Sanam al Nakah, (The Camel's Hump), referring to the contemporaneous Persian figure. • Gamma Cassiopeiae is a shell star, a type of variable star that has a very high rate of rotation. This causes the star to be somewhat unstable and periodically eject rings of material. Gamma Cassiopeiae has a minimum magnitude of 3.0 and a maximum magnitude of 1.6; it is currently approximately magnitude 2.2. -
Reading Hypermedia Narrative Stars, 88 Constellations for Wittgenstein by David Clark
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Crossref Artigo Original http://dx.doi.org/10.5007/1807-9288.2015v11n1p287 READING HYPERMEDIA NARRATIVE STARS, 88 CONSTELLATIONS FOR WITTGENSTEIN BY DAVID CLARK. ANALYTICAL APPROACH TO CONSTELLATION 18 CASSIOPEIA Nohelia Meza* ABSTRACT: This article presents an approach to analyze hypermedia discourse elements found in Cassiopeia, one of the constellations that compose 88 Constellations for Wittgenstein (To Be Played with the Left Hand) (2011) by net.art artist David Clark. Even though there are many approaches to the subject of electronic literature, there are still many unexplored e-lit works waiting to be studied that undoubtedly will raise questions about the literariness of electronic literature. This article briefly outlines issues of representation, temporality, semiotics, interaction, and manipulation on this specific constellation of the aforementioned e-lit work. Specific new media literary theories (temporal possibilities in programmed texts; temporal levels for cybertexts with narrative content; pluricode couplings, lability of digital works) have been applied to the selected corpus in order to examine the nuances and gradations of electronic textuality and literary reception. The analysis shows that the user‘s manipulation and interaction with the e-lit work affect certain elements in the hypermedia narrative discourse so as to suggest new possibilities of temporal and semiotic interpretation. KEYWORDS: Discourse Analysis. Electronic Literature. Narrativity. Semiotics. Temporality. Introduction In this article, I present an analytical approach to constellation number 18, Cassiopeia, one of the star clusters that composes David Clark‘s e-lit work, 88 Constellations for Wittgenstein (To Be Played with the Left Hand) (2011). -
The Caldwell Catalogue Contents
The Caldwell Catalogue Contents 1 Overview 1 1.1 Caldwell catalogue ........................................... 1 1.1.1 Caldwell Star Chart ...................................... 1 1.1.2 Number of objects by type in the Caldwell catalogue. .................... 1 1.1.3 Caldwell objects ....................................... 1 1.1.4 See also ............................................ 2 1.1.5 References .......................................... 2 1.1.6 External links ......................................... 2 1.2 Patrick Moore ............................................. 2 1.2.1 Early life ........................................... 2 1.2.2 Career in astronomy ...................................... 3 1.2.3 Activism and political beliefs ................................. 5 1.2.4 Other interests and popular culture .............................. 5 1.2.5 Honours and appointments .................................. 6 1.2.6 Bibliography ......................................... 7 1.2.7 Film and television appearances ................................ 7 1.2.8 See also ............................................ 7 1.2.9 References .......................................... 7 1.2.10 External links ......................................... 9 2 Objects 10 2.1 Caldwell 1 ............................................... 10 2.1.1 References .......................................... 10 2.1.2 External links ......................................... 10 2.2 Caldwell 2 ............................................... 10 2.2.1 Gallery ...........................................