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Planetary Nebulae
Planetary Nebulae A planetary nebula is a kind of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from old red giant stars late in their lives. The term "planetary nebula" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years. The mechanism for formation of most planetary nebulae is thought to be the following: at the end of the star's life, during the red giant phase, the outer layers of the star are expelled by strong stellar winds. Eventually, after most of the red giant's atmosphere is dissipated, the exposed hot, luminous core emits ultraviolet radiation to ionize the ejected outer layers of the star. Absorbed ultraviolet light energizes the shell of nebulous gas around the central star, appearing as a bright colored planetary nebula at several discrete visible wavelengths. Planetary nebulae may play a crucial role in the chemical evolution of the Milky Way, returning material to the interstellar medium from stars where elements, the products of nucleosynthesis (such as carbon, nitrogen, oxygen and neon), have been created. Planetary nebulae are also observed in more distant galaxies, yielding useful information about their chemical abundances. In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies. -
A Basic Requirement for Studying the Heavens Is Determining Where In
Abasic requirement for studying the heavens is determining where in the sky things are. To specify sky positions, astronomers have developed several coordinate systems. Each uses a coordinate grid projected on to the celestial sphere, in analogy to the geographic coordinate system used on the surface of the Earth. The coordinate systems differ only in their choice of the fundamental plane, which divides the sky into two equal hemispheres along a great circle (the fundamental plane of the geographic system is the Earth's equator) . Each coordinate system is named for its choice of fundamental plane. The equatorial coordinate system is probably the most widely used celestial coordinate system. It is also the one most closely related to the geographic coordinate system, because they use the same fun damental plane and the same poles. The projection of the Earth's equator onto the celestial sphere is called the celestial equator. Similarly, projecting the geographic poles on to the celest ial sphere defines the north and south celestial poles. However, there is an important difference between the equatorial and geographic coordinate systems: the geographic system is fixed to the Earth; it rotates as the Earth does . The equatorial system is fixed to the stars, so it appears to rotate across the sky with the stars, but of course it's really the Earth rotating under the fixed sky. The latitudinal (latitude-like) angle of the equatorial system is called declination (Dec for short) . It measures the angle of an object above or below the celestial equator. The longitud inal angle is called the right ascension (RA for short). -
Astronomy 2008 Index
Astronomy Magazine Article Title Index 10 rising stars of astronomy, 8:60–8:63 1.5 million galaxies revealed, 3:41–3:43 185 million years before the dinosaurs’ demise, did an asteroid nearly end life on Earth?, 4:34–4:39 A Aligned aurorae, 8:27 All about the Veil Nebula, 6:56–6:61 Amateur astronomy’s greatest generation, 8:68–8:71 Amateurs see fireballs from U.S. satellite kill, 7:24 Another Earth, 6:13 Another super-Earth discovered, 9:21 Antares gang, The, 7:18 Antimatter traced, 5:23 Are big-planet systems uncommon?, 10:23 Are super-sized Earths the new frontier?, 11:26–11:31 Are these space rocks from Mercury?, 11:32–11:37 Are we done yet?, 4:14 Are we looking for life in the right places?, 7:28–7:33 Ask the aliens, 3:12 Asteroid sleuths find the dino killer, 1:20 Astro-humiliation, 10:14 Astroimaging over ancient Greece, 12:64–12:69 Astronaut rescue rocket revs up, 11:22 Astronomers spy a giant particle accelerator in the sky, 5:21 Astronomers unearth a star’s death secrets, 10:18 Astronomers witness alien star flip-out, 6:27 Astronomy magazine’s first 35 years, 8:supplement Astronomy’s guide to Go-to telescopes, 10:supplement Auroral storm trigger confirmed, 11:18 B Backstage at Astronomy, 8:76–8:82 Basking in the Sun, 5:16 Biggest planet’s 5 deepest mysteries, The, 1:38–1:43 Binary pulsar test affirms relativity, 10:21 Binocular Telescope snaps first image, 6:21 Black hole sets a record, 2:20 Black holes wind up galaxy arms, 9:19 Brightest starburst galaxy discovered, 12:23 C Calling all space probes, 10:64–10:65 Calling on Cassiopeia, 11:76 Canada to launch new asteroid hunter, 11:19 Canada’s handy robot, 1:24 Cannibal next door, The, 3:38 Capture images of our local star, 4:66–4:67 Cassini confirms Titan lakes, 12:27 Cassini scopes Saturn’s two-toned moon, 1:25 Cassini “tastes” Enceladus’ plumes, 7:26 Cepheus’ fall delights, 10:85 Choose the dome that’s right for you, 5:70–5:71 Clearing the air about seeing vs. -
September 2020 BRAS Newsletter
A Neowise Comet 2020, photo by Ralf Rohner of Skypointer Photography Monthly Meeting September 14th at 7:00 PM, via Jitsi (Monthly meetings are on 2nd Mondays at Highland Road Park Observatory, temporarily during quarantine at meet.jit.si/BRASMeets). GUEST SPEAKER: NASA Michoud Assembly Facility Director, Robert Champion What's In This Issue? President’s Message Secretary's Summary Business Meeting Minutes Outreach Report Asteroid and Comet News Light Pollution Committee Report Globe at Night Member’s Corner –My Quest For A Dark Place, by Chris Carlton Astro-Photos by BRAS Members Messages from the HRPO REMOTE DISCUSSION Solar Viewing Plus Night Mercurian Elongation Spooky Sensation Great Martian Opposition Observing Notes: Aquila – The Eagle Like this newsletter? See PAST ISSUES online back to 2009 Visit us on Facebook – Baton Rouge Astronomical Society Baton Rouge Astronomical Society Newsletter, Night Visions Page 2 of 27 September 2020 President’s Message Welcome to September. You may have noticed that this newsletter is showing up a little bit later than usual, and it’s for good reason: release of the newsletter will now happen after the monthly business meeting so that we can have a chance to keep everybody up to date on the latest information. Sometimes, this will mean the newsletter shows up a couple of days late. But, the upshot is that you’ll now be able to see what we discussed at the recent business meeting and have time to digest it before our general meeting in case you want to give some feedback. Now that we’re on the new format, business meetings (and the oft neglected Light Pollution Committee Meeting), are going to start being open to all members of the club again by simply joining up in the respective chat rooms the Wednesday before the first Monday of the month—which I encourage people to do, especially if you have some ideas you want to see the club put into action. -
IPHAS Extinction Distances to Planetary Nebulae
A&A 525, A58 (2011) Astronomy DOI: 10.1051/0004-6361/201014464 & c ESO 2010 Astrophysics IPHAS extinction distances to planetary nebulae C. Giammanco1,12,S.E.Sale2,R.L.M.Corradi1,12,M.J.Barlow3, K. Viironen1,13,14,L.Sabin4, M. Santander-García5,1,12,D.J.Frew6,R.Greimel7, B. Miszalski10, S. Phillipps8, A. A. Zijlstra9, A. Mampaso1,12,J.E.Drew2,10,Q.A.Parker6,11, and R. Napiwotzki10 1 Instituto de Astrofísica de Canarias (IAC), C/ vía Láctea s/n, 38200 La Laguna, Spain e-mail: [email protected] 2 Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ, UK 3 Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK 4 Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 877, 22800 Ensenada, B.C., Mexico 5 Isaac Newton Group of Telescopes, Ap. de Correos 321, 38700 Sta. Cruz de la Palma, Spain 6 Department of Physics, Macquarie University, NSW 2109, Australia 7 Institut für Physik, Karl-Franzens Universität Graz, Universitätsplatz 5, 8010 Graz, Austria 8 Astrophysics Group, Department of Physics, Bristol University, Tyndall Avenue, Bristol BS8 1TL, UK 9 Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, M13 9PL Manchester, UK 10 Centre for Astrophysics Research, STRI, University of Hertfordshire, College Lane Campus, Hatfield AL10 9AB, UK 11 Anglo-Australian Observatory, PO Box 296, Epping, NSW 1710, Australia 12 Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain 13 Centro Astronómico Hispano Alemán, Calar Alto, C/Jesús Durbán Remón 2-2, 04004 Almeria, Spain 14 Centro de Estudios de Física del Cosmos de Aragón (CEFCA), C/General Pizarro 1-1, 44001 Teruel, Spain Received 19 March 2010 / Accepted 3 July 2010 ABSTRACT Aims. -
SAC's 110 Best of the NGC
SAC's 110 Best of the NGC by Paul Dickson Version: 1.4 | March 26, 1997 Copyright °c 1996, by Paul Dickson. All rights reserved If you purchased this book from Paul Dickson directly, please ignore this form. I already have most of this information. Why Should You Register This Book? Please register your copy of this book. I have done two book, SAC's 110 Best of the NGC and the Messier Logbook. In the works for late 1997 is a four volume set for the Herschel 400. q I am a beginner and I bought this book to get start with deep-sky observing. q I am an intermediate observer. I bought this book to observe these objects again. q I am an advance observer. I bought this book to add to my collect and/or re-observe these objects again. The book I'm registering is: q SAC's 110 Best of the NGC q Messier Logbook q I would like to purchase a copy of Herschel 400 book when it becomes available. Club Name: __________________________________________ Your Name: __________________________________________ Address: ____________________________________________ City: __________________ State: ____ Zip Code: _________ Mail this to: or E-mail it to: Paul Dickson 7714 N 36th Ave [email protected] Phoenix, AZ 85051-6401 After Observing the Messier Catalog, Try this Observing List: SAC's 110 Best of the NGC [email protected] http://www.seds.org/pub/info/newsletters/sacnews/html/sac.110.best.ngc.html SAC's 110 Best of the NGC is an observing list of some of the best objects after those in the Messier Catalog. -
Catalogue of Excitation Classes P for 750 Galactic Planetary Nebulae
Catalogue of Excitation Classes p for 750 Galactic Planetary Nebulae Name p Name p Name p Name p NeC 40 1 Nee 6072 9 NeC 6881 10 IC 4663 11 NeC 246 12+ Nee 6153 3 NeC 6884 7 IC 4673 10 NeC 650-1 10 Nee 6210 4 NeC 6886 9 IC 4699 9 NeC 1360 12 Nee 6302 10 Nee 6891 4 IC 4732 5 NeC 1501 10 Nee 6309 10 NeC 6894 10 IC 4776 2 NeC 1514 8 NeC 6326 9 Nee 6905 11 IC 4846 3 NeC 1535 8 Nee 6337 11 Nee 7008 11 IC 4997 8 NeC 2022 12 Nee 6369 4 NeC 7009 7 IC 5117 6 NeC 2242 12+ NeC 6439 8 NeC 7026 9 IC 5148-50 6 NeC 2346 9 NeC 6445 10 Nee 7027 11 IC 5217 6 NeC 2371-2 12 Nee 6537 11 Nee 7048 11 Al 1 NeC 2392 10 NeC 6543 5 Nee 7094 12 A2 10 NeC 2438 10 NeC 6563 8 NeC 7139 9 A4 10 NeC 2440 10 NeC 6565 7 NeC 7293 7 A 12 4 NeC 2452 10 NeC 6567 4 Nee 7354 10 A 15 12+ NeC 2610 12 NeC 6572 7 NeC 7662 10 A 20 12+ NeC 2792 11 NeC 6578 2 Ie 289 12 A 21 1 NeC 2818 11 NeC 6620 8 IC 351 10 A 23 4 NeC 2867 9 NeC 6629 5 Ie 418 1 A 24 1 NeC 2899 10 Nee 6644 7 IC 972 10 A 30 12+ NeC 3132 9 NeC 6720 10 IC 1295 10 A 33 11 NeC 3195 9 NeC 6741 9 IC 1297 9 A 35 1 NeC 3211 10 NeC 6751 9 Ie 1454 10 A 36 12+ NeC 3242 9 Nee 6765 10 IC1747 9 A 40 2 NeC 3587 8 NeC 6772 9 IC 2003 10 A 41 1 NeC 3699 9 NeC 6778 9 IC 2149 2 A 43 2 NeC 3918 9 NeC 6781 8 IC 2165 10 A 46 2 NeC 4071 11 NeC 6790 4 IC 2448 9 A 49 4 NeC 4361 12+ NeC 6803 5 IC 2501 3 A 50 10 NeC 5189 10 NeC 6804 12 IC 2553 8 A 51 12 NeC 5307 9 NeC 6807 4 IC 2621 9 A 54 12 NeC 5315 2 NeC 6818 10 Ie 3568 3 A 55 4 NeC 5873 10 NeC 6826 11 Ie 4191 6 A 57 3 NeC 5882 6 NeC 6833 2 Ie 4406 4 A 60 2 NeC 5879 12 NeC 6842 2 IC 4593 6 A -
Redalyc.3D Photoionization Structure and Distances of Planetary Nebulae III. NGC 6781
Exacta ISSN: 1678-5428 [email protected] Universidade Nove de Julho Brasil Schwarz, Hugo E.; Monteiro, Hektor 3D photoionization structure and distances of Planetary Nebulae III. NGC 6781 Exacta, vol. 4, núm. 2, 2006, pp. 281-288 Universidade Nove de Julho São Paulo, Brasil Disponível em: http://www.redalyc.org/articulo.oa?id=81040207 Como citar este artigo Número completo Sistema de Informação Científica Mais artigos Rede de Revistas Científicas da América Latina, Caribe , Espanha e Portugal Home da revista no Redalyc Projeto acadêmico sem fins lucrativos desenvolvido no âmbito da iniciativa Acesso Aberto Artigos 3D photoionization structure and distances of Planetary Nebulae III. NGC 67811 Hugo E. Schwarz1, Hektor Monteiro2 1Cerro Tololo Inter-American Observatory, Casilla 603, Colina El Pino s/n, La Serena [Chile] 2Department of Physics and Astronomy, Georgia State University, Park Place South, Atlanta, GA 30302 [United States of America] Nucleo de Astrofisica-CETEC- Unicsul . [email protected] Continuing our series of papers on the three-dimensional (3D) structures and accurate distances to Planetary Nebulae (PNe), we present our study of the planetary nebula NGC6781. For this object we construct a 3D photoionization model and, using the constraints provided by observational data from the literature we determine the detailed 3D structure of the nebula, the physical parameters of the ionizing source and the first precise distance. The procedure consists in simultaneously fitting all the observed emission line morphologies, integrated intensities and the two-dimensional (2D) density map from the [SII] (sulfur II) line ratios to the parameters generated by the model, and in an iterative way obtain the best fit for the cen- tral star parameters and the distance to NGC6781, obtaining values of 950±143 pc (parsec – astronomic distance unit) and 385 LΘ (solar luminosity) for the distance and luminosity of the central star respectively. -
Curriculum Vitae of You-Hua Chu
Curriculum Vitae of You-Hua Chu Address and Telephone Number: Institute of Astronomy and Astrophysics, Academia Sinica 11F of Astronomy-Mathematics Building, AS/NTU No.1, Sec. 4, Roosevelt Rd, Taipei 10617 Taiwan, R.O.C. Tel: (886) 02 2366 5300 E-mail address: [email protected] Academic Degrees, Granting Institutions, and Dates Granted: B.S. Physics Dept., National Taiwan University 1975 Ph.D. Astronomy Dept., University of California at Berkeley 1981 Professional Employment History: 2014 Sep - present Director, Institute of Astronomy and Astrophysics, Academia Sinica 2014 Jul - present Distinguished Research Fellow, Institute of Astronomy and Astrophysics, Academia Sinica 2014 Jul - present Professor Emerita, University of Illinois at Urbana-Champaign 2005 Aug - 2011 Jul Chair of Astronomy Dept., University of Illinois at Urbana-Champaign 1997 Aug - 2014 Jun Professor, University of Illinois at Urbana-Champaign 1992 Aug - 1997 Jul Research Associate Professor, University of Illinois at Urbana-Champaign 1987 Jan - 1992 Aug Research Assistant Professor, University of Illinois at Urbana-Champaign 1985 Feb - 1986 Dec Graduate College Scholar, University of Illinois at Urbana-Champaign 1984 Sep - 1985 Jan Lindheimer Fellow, Northwestern University 1982 May - 1984 Jun Postdoctoral Research Associate, University of Wisconsin at Madison 1981 Oct - 1982 May Postdoctoral Research Associate, University of Illinois at Urbana-Champaign 1981 Jun - 1981 Aug Postdoctoral Research Associate, University of California at Berkeley Committees Served: -
How to Construct a 3D Model of the Planetary Nebula NGC 6781 with SHAPE
How to construct a 3D model of the planetary nebula NGC 6781 with SHAPE Josefine Bergstedt, 850506-1484 June 30, 2015 Uppsala University, Department of Physics and Astronomy Bachelor of Science Degree in Physics, VT -15 Supervisor: Sofia Ramstedt Referee: Kjell Eriksson Sammanfattning Målet med det här arbetet är att i dataprogrammet SHAPE konstruera en 3D-modell av den planetariska nebulosan NGC 6781. En planetarisk nebulosa bildas när en viss typ av stjärnor, med en ur- sprunglig massa mellan 0.8-8 M (där M står för solmassan) har nått slut- fasen i sin utveckling och är på väg att avsluta sina liv. I denna slutfas uppkommer pulsationer hos stjärnan samt en stark vind som tillsammans blåser bort de yttre, sfäriska lagren av stjärnan tills endast den innersta kär- nan återstår. Kärnan kommer att svalna av och blir till slut en så kallad vit dvärg vilken omges av ett skal bestående av den utkastade gasen och stoftet från stjärnans yttre lager. Detta expanderande skal bestående av lysande, joniserad gas är vad som kallas för planetarisk nebulosa. Ordet "nebulosa" är latin och betyder moln eller dimma, namnen plane- tarisk nebulosa uppkom på 1780-talet då man först observerade dessa objekt och tyckte de liknade stora gasplaneter. Planetariska nebulosor förekommer i flera olika former, allt från bipolär till väldigt komplexa strukturer. Den snabba vinden tillsammans med den starka strålning som kommer från stjär- nan antas vara orsaken till att planetariska nebulosor uppkommer. Exakt hur dessa processer fungerar samt vilka mekanismer som påverkar att stjär- nans yttre sfäriska lager kan anta de spektakulära former som planetariska nebulosor har är något som man i dagsläget inte vet med säkerhet. -
OBSERVATIONS at 2700 Mhz of SELECTED PLANETARY NEBULAE
OBSERVATIONS AT 2700 MHz OF SELECTED PLANETARY NEBULAE By L. H. ALLER* and D. K. MILNEt [Manuscrip:t received 15 July 1971] Ab8tract Observations at 2700 MHz of 74 planetary nebulae have been obtained with the Parkes 64 m radio telescope. Comparison is made with the optically determined Hfl intensity to obtain extinction coefficients in these directions. 1. INTRODUCTION Radiofrequency observations of numerous planetary nebulae have been obtained by many investigators using a variety of equipment; an excellent com pilation and bibliography has been given by Higgs (1971). The radio emission, which is relatively weak, is due to free-free transitions within the ionized hydrogen cloud. Consequently there is a relationship between the intrinsic luminosities at radio and optical frequencies, which can be used to determine the optical absorption to the nebula. In the present investigation the 64 m radio telescope at Parkes was used to obtain radio positions and 2700 MHz flux densities of 74 planetary nebulae south of declination +27°. These flux densities are compared with the optically determined H,8 intensities to obtain extinction coefficients for these nebulae. The preliminary results for 17 of the nebulae were given by Aller (1969a, 1969b). II. OBSERVATIONS The 2700 MHz parametric correlation receiver (Batchelor, Brooks, and Cooper 1968) has a system noise temperature of 100 K. With the 400 MHz bandwidth and an output time constant of 1 s the r.m.s. noise is equivalent to 0 ·05 f.u.t This is a considerably better sensitivity than was used in a previous Parkes survey of planetary nebulae by Slee and Orchiston (1965). -
2020 Flyin' High Over X
The Eldorado Star Party 2020 Telescope Observing Club by Bill Flanagan Houston Astronomical Society Purpose and Rules Welcome to the Annual ESP Telescope Club! The main purpose of this club is to give you an opportunity to observe some of the showpiece objects of the fall season under the pristine skies of Southwest Texas. We have also included a few items on the observing lists that may challenge you to observe some fainter and more obscure objects that present themselves at their very best under the dark skies of the Eldorado Star Party. The rules are simple; just observe the required number of objects on the observing list while you are at the Eldorado Star Party to receive a club badge. Flyin’High Over X Bar In early autumn, just after evening twilight, there are a number of winged creatures flying high in the skies of West Texas. Gliding along the glow of the Milky Way is both Aquila the eagle and Cygnus the swan. Just before midnight and directly overhead is the great winged horse Pegasus. Around midnight and looking to the south we can see a phoenix soaring across the southern horizon. So what better time and place to see what celestial gems these great winged creatures bring us as they fly high over the X Bar Ranch. Given this great autumn opportunity, the Telescope Observing Club program for the 2020 Eldorado Star Party is “Flyin’ High Over X Bar.” The program is a list of 28 objects located in the four constellations mentioned above, Aquila, Cygnus, Pegasus and Phoenix.