Astronomy November
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Astronomie in Theorie Und Praxis 8. Auflage in Zwei Bänden Erik Wischnewski
Astronomie in Theorie und Praxis 8. Auflage in zwei Bänden Erik Wischnewski Inhaltsverzeichnis 1 Beobachtungen mit bloßem Auge 37 Motivation 37 Hilfsmittel 38 Drehbare Sternkarte Bücher und Atlanten Kataloge Planetariumssoftware Elektronischer Almanach Sternkarten 39 2 Atmosphäre der Erde 49 Aufbau 49 Atmosphärische Fenster 51 Warum der Himmel blau ist? 52 Extinktion 52 Extinktionsgleichung Photometrie Refraktion 55 Szintillationsrauschen 56 Angaben zur Beobachtung 57 Durchsicht Himmelshelligkeit Luftunruhe Beispiel einer Notiz Taupunkt 59 Solar-terrestrische Beziehungen 60 Klassifizierung der Flares Korrelation zur Fleckenrelativzahl Luftleuchten 62 Polarlichter 63 Nachtleuchtende Wolken 64 Haloerscheinungen 67 Formen Häufigkeit Beobachtung Photographie Grüner Strahl 69 Zodiakallicht 71 Dämmerung 72 Definition Purpurlicht Gegendämmerung Venusgürtel Erdschattenbogen 3 Optische Teleskope 75 Fernrohrtypen 76 Refraktoren Reflektoren Fokus Optische Fehler 82 Farbfehler Kugelgestaltsfehler Bildfeldwölbung Koma Astigmatismus Verzeichnung Bildverzerrungen Helligkeitsinhomogenität Objektive 86 Linsenobjektive Spiegelobjektive Vergütung Optische Qualitätsprüfung RC-Wert RGB-Chromasietest Okulare 97 Zusatzoptiken 100 Barlow-Linse Shapley-Linse Flattener Spezialokulare Spektroskopie Herschel-Prisma Fabry-Pérot-Interferometer Vergrößerung 103 Welche Vergrößerung ist die Beste? Blickfeld 105 Lichtstärke 106 Kontrast Dämmerungszahl Auflösungsvermögen 108 Strehl-Zahl Luftunruhe (Seeing) 112 Tubusseeing Kuppelseeing Gebäudeseeing Montierungen 113 Nachführfehler -
The Puzzle of the Strange Galaxy Made of 99.9% Dark Matter Is Solved 13 October 2020
The puzzle of the strange galaxy made of 99.9% dark matter is solved 13 October 2020 The galaxy Dragonfly 44 was discovered in a deep survey of the Coma cluster, a cluster with several thousand galaxies. From the start, the galaxy was considered remarkable by the researchers because the quantity of dark matter they inferred was almost as much as that in the Milky Way, the equivalent of a billion solar masses. However, instead of containing around a hundred thousand million stars, as has the Milky Way, DF44 has only a hundred million stars, a thousand times Image and amplification (in color) of the ultra-diffuse fewer. This means that the amount of dark matter galaxy Dragonfly 44 taken with the Hubble space was ten thousand times greater than that of its telescope. Credit: Teymoor Saifollahi and NASA/HST. stars. If this had been true, it would have been a unique object, with almost 100 times as much dark matter as that expected from the number of its stars. At present, the formation of galaxies is difficult to understand without the presence of a ubiquitous, Nevertheless, by an exhaustive analysis of the but mysterious component, termed dark matter. system of globular cluster around Dragonfly 44, the Astronomers have measure how much dark matter researchers have detected that the total number of there is around galaxies, and have found that it globular clusters is only 20, and that the total varies between 10 and 300 times the quantity of quantity of dark matter is around 300 times that of visible matter. -
Lenticular Galaxy, a Bit Spiral, a Bit Elliptical
Lenticular galaxy, a bit spiral, a bit elliptical Domingos Soares Lenticular galaxies were the last to be included in the morphological classification of galaxies designed by the American astronomer Edwin Hubble (1889-1953). Morphology refers to the shapes of galaxies. The lenticular are galaxies whose stars are distributed in the form of a disk and a central spheroid, like spiral galaxies, but they do not have spiral arms. Besides, they are \clean", like elliptical galaxies, that is, they lack interstellar gas and dust, but unlike those, they do not show a global spheroidal shape. All in all, lenticular galaxies have a bit of each one of the two classes of galaxies. When Hubble put forward his classification of galaxies, for the first time, in 1926, the lenticular class was not recognized. But through the years, Hub- ble began to believe that there should be a class of galaxies that could make a bridge between ellipticals, that have the general form of a spheroid, and spiral galaxies, that are predominantly disk galaxies, with bright and majes- tic arms. In his 1936 book, \The Realm of the Nebulae", he included this class in his galaxy tunning fork. The elliptical galaxies were in the handle of the tunning fork and the spiral galaxies, with and without bars, in the two arms of the fork. In the vertex of the tunning fork, representing a morpho- logical transition between ellipticals and spirals, he postulated the existence of a new class, that of the lenticular galaxies. They were designated by the letter \S" followed by \0", that is, S0. -
Messier Objects
Messier Objects From the Stocker Astroscience Center at Florida International University Miami Florida The Messier Project Main contributors: • Daniel Puentes • Steven Revesz • Bobby Martinez Charles Messier • Gabriel Salazar • Riya Gandhi • Dr. James Webb – Director, Stocker Astroscience center • All images reduced and combined using MIRA image processing software. (Mirametrics) What are Messier Objects? • Messier objects are a list of astronomical sources compiled by Charles Messier, an 18th and early 19th century astronomer. He created a list of distracting objects to avoid while comet hunting. This list now contains over 110 objects, many of which are the most famous astronomical bodies known. The list contains planetary nebula, star clusters, and other galaxies. - Bobby Martinez The Telescope The telescope used to take these images is an Astronomical Consultants and Equipment (ACE) 24- inch (0.61-meter) Ritchey-Chretien reflecting telescope. It has a focal ratio of F6.2 and is supported on a structure independent of the building that houses it. It is equipped with a Finger Lakes 1kx1k CCD camera cooled to -30o C at the Cassegrain focus. It is equipped with dual filter wheels, the first containing UBVRI scientific filters and the second RGBL color filters. Messier 1 Found 6,500 light years away in the constellation of Taurus, the Crab Nebula (known as M1) is a supernova remnant. The original supernova that formed the crab nebula was observed by Chinese, Japanese and Arab astronomers in 1054 AD as an incredibly bright “Guest star” which was visible for over twenty-two months. The supernova that produced the Crab Nebula is thought to have been an evolved star roughly ten times more massive than the Sun. -
Winter Constellations
Winter Constellations *Orion *Canis Major *Monoceros *Canis Minor *Gemini *Auriga *Taurus *Eradinus *Lepus *Monoceros *Cancer *Lynx *Ursa Major *Ursa Minor *Draco *Camelopardalis *Cassiopeia *Cepheus *Andromeda *Perseus *Lacerta *Pegasus *Triangulum *Aries *Pisces *Cetus *Leo (rising) *Hydra (rising) *Canes Venatici (rising) Orion--Myth: Orion, the great hunter. In one myth, Orion boasted he would kill all the wild animals on the earth. But, the earth goddess Gaia, who was the protector of all animals, produced a gigantic scorpion, whose body was so heavily encased that Orion was unable to pierce through the armour, and was himself stung to death. His companion Artemis was greatly saddened and arranged for Orion to be immortalised among the stars. Scorpius, the scorpion, was placed on the opposite side of the sky so that Orion would never be hurt by it again. To this day, Orion is never seen in the sky at the same time as Scorpius. DSO’s ● ***M42 “Orion Nebula” (Neb) with Trapezium A stellar nursery where new stars are being born, perhaps a thousand stars. These are immense clouds of interstellar gas and dust collapse inward to form stars, mainly of ionized hydrogen which gives off the red glow so dominant, and also ionized greenish oxygen gas. The youngest stars may be less than 300,000 years old, even as young as 10,000 years old (compared to the Sun, 4.6 billion years old). 1300 ly. 1 ● *M43--(Neb) “De Marin’s Nebula” The star-forming “comma-shaped” region connected to the Orion Nebula. ● *M78--(Neb) Hard to see. A star-forming region connected to the Orion Nebula. -
Multicolor Surface Photometry of Lenticular Galaxies
The Astronomical Journal, 129:630–646, 2005 February # 2005. The American Astronomical Society. All rights reserved. Printed in U.S.A. MULTICOLOR SURFACE PHOTOMETRY OF LENTICULAR GALAXIES. I. THE DATA Sudhanshu Barway School of Studies in Physics, Pandit Ravishankar Shukla University, Raipur 492010, India; [email protected] Y. D. Mayya Instituto Nacional de Astrofisı´ca, O´ ptica y Electro´nica, Apdo. Postal 51 y 216, Luis Enrique Erro 1, 72000 Tonantzintla, Pue., Mexico; [email protected] Ajit K. Kembhavi Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411007, India; [email protected] and S. K. Pandey1 School of Studies in Physics, Pandit Ravishankar Shukla University, Raipur 492010, India; [email protected] Receivedv 2003 Auggust 13; accepted 2004 October 20 ABSTRACT We present multicolor surface and aperture photometry in the B, V, R,andK0 bands for a sample of 34 lenticular galaxies from the Uppsala General Catalogue. From surface photometric analysis, we obtain radial profiles of surface brightness, colors, ellipticity, position angle, and the Fourier coefficients that describe the departure of isophotal shapes from a purely elliptical form; we find the presence of dust lanes, patches, and ringlike structure in several galaxies in the sample. We obtain total integrated magnitudes and colors and find that these are in good agreement with the values from the Third Reference Catalogue. Isophotal colors are correlated with each other, following the sequence expected for early-type galaxies. The color gradients in lenticular galaxies are more negative than the corresponding gradients in elliptical galaxies. There is a good correlation between BÀVand BÀR color gradients, and the mean gradients in the BÀV, BÀR,andVÀK0 colors are À0:13 Æ 0:06, À0:18 Æ 0:06, and À0:25 Æ 0:11 mag dexÀ1 in radius, respectively. -
CONSTELLATION TRIANGULUM, the TRIANGLE Triangulum Is a Small Constellation in the Northern Sky
CONSTELLATION TRIANGULUM, THE TRIANGLE Triangulum is a small constellation in the northern sky. Its name is Latin for "triangle", derived from its three brightest stars, which form a long and narrow triangle. Known to the ancient Babylonians and Greeks, Triangulum was one of the 48 constellations listed by the 2nd century astronomer Ptolemy. The celestial cartographers Johann Bayer and John Flamsteed catalogued the constellation's stars, giving six of them Bayer designations. The white stars Beta and Gamma Trianguli, of apparent magnitudes 3.00 and 4.00, respectively, form the base of the triangle and the yellow-white Alpha Trianguli, of magnitude 3.41, the apex. Iota Trianguli is a notable double star system, and there are three star systems with planets located in Triangulum. The constellation contains several galaxies, the brightest and nearest of which is the Triangulum Galaxy or Messier 33—a member of the Local Group. The first quasar ever observed, 3C 48, also lies within Triangulum's boundaries. HISTORY AND MYTHOLOGY In the Babylonian star catalogues, Triangulum, together with Gamma Andromedae, formed the constellation known as MULAPIN "The Plough". It is notable as the first constellation presented on (and giving its name to) a pair of tablets containing canonical star lists that were compiled around 1000 BC, the MUL.APIN. The Plough was the first constellation of the "Way of Enlil"—that is, the northernmost quarter of the Sun's path, which corresponds to the 45 days on either side of summer solstice. Its first appearance in the pre-dawn sky (heliacal rising) in February marked the time to begin spring ploughing in Mesopotamia. -
Wynyard Planetarium & Observatory a Autumn Observing Notes
Wynyard Planetarium & Observatory A Autumn Observing Notes Wynyard Planetarium & Observatory PUBLIC OBSERVING – Autumn Tour of the Sky with the Naked Eye CASSIOPEIA Look for the ‘W’ 4 shape 3 Polaris URSA MINOR Notice how the constellations swing around Polaris during the night Pherkad Kochab Is Kochab orange compared 2 to Polaris? Pointers Is Dubhe Dubhe yellowish compared to Merak? 1 Merak THE PLOUGH Figure 1: Sketch of the northern sky in autumn. © Rob Peeling, CaDAS, 2007 version 1.2 Wynyard Planetarium & Observatory PUBLIC OBSERVING – Autumn North 1. On leaving the planetarium, turn around and look northwards over the roof of the building. Close to the horizon is a group of stars like the outline of a saucepan with the handle stretching to your left. This is the Plough (also called the Big Dipper) and is part of the constellation Ursa Major, the Great Bear. The two right-hand stars are called the Pointers. Can you tell that the higher of the two, Dubhe is slightly yellowish compared to the lower, Merak? Check with binoculars. Not all stars are white. The colour shows that Dubhe is cooler than Merak in the same way that red-hot is cooler than white- hot. 2. Use the Pointers to guide you upwards to the next bright star. This is Polaris, the Pole (or North) Star. Note that it is not the brightest star in the sky, a common misconception. Below and to the left are two prominent but fainter stars. These are Kochab and Pherkad, the Guardians of the Pole. Look carefully and you will notice that Kochab is slightly orange when compared to Polaris. -
The Dynamical State of the Coma Cluster with XMM-Newton?
A&A 400, 811–821 (2003) Astronomy DOI: 10.1051/0004-6361:20021911 & c ESO 2003 Astrophysics The dynamical state of the Coma cluster with XMM-Newton? D. M. Neumann1,D.H.Lumb2,G.W.Pratt1, and U. G. Briel3 1 CEA/DSM/DAPNIA Saclay, Service d’Astrophysique, L’Orme des Merisiers, Bˆat. 709, 91191 Gif-sur-Yvette, France 2 Science Payloads Technology Division, Research and Science Support Dept., ESTEC, Postbus 299 Keplerlaan 1, 2200AG Noordwijk, The Netherlands 3 Max-Planck Institut f¨ur extraterrestrische Physik, Giessenbachstr., 85740 Garching, Germany Received 19 June 2002 / Accepted 13 December 2002 Abstract. We present in this paper a substructure and spectroimaging study of the Coma cluster of galaxies based on XMM- Newton data. XMM-Newton performed a mosaic of observations of Coma to ensure a large coverage of the cluster. We add the different pointings together and fit elliptical beta-models to the data. We subtract the cluster models from the data and look for residuals, which can be interpreted as substructure. We find several significant structures: the well-known subgroup connected to NGC 4839 in the South-West of the cluster, and another substructure located between NGC 4839 and the centre of the Coma cluster. Constructing a hardness ratio image, which can be used as a temperature map, we see that in front of this new structure the temperature is significantly increased (higher or equal 10 keV). We interpret this temperature enhancement as the result of heating as this structure falls onto the Coma cluster. We furthermore reconfirm the filament-like structure South-East of the cluster centre. -
Spiral Galaxies, Elliptical Galaxies, Irregular Galaxies, Dwarf Galaxies, Peculiar/Interacting Galalxies Spiral Galaxies
Lecture 33: Announcements 1) Pick up graded hwk 5. Good job: Jessica, Jessica, and Elizabeth for a 100% score on hwk 5 and the other 25% of the class with an A. 2) Article and homework 7 were posted on class website on Monday (Apr 18) . Due on Mon Apr 25. 3) Reading Assignment for Quiz Wed Apr 27 Ch 23, Cosmic Perspectives: The Beginning of Time 4) Exam moved to Wed May 4 Lecture 33: Galaxy Formation and Evolution Several topics for galaxy evolution have already been covered in Lectures 2, 3, 4,14,15,16. you should refer to your in-class notes for these topics which include: - Types of galaxies (barred spiral, unbarred spirals, ellipticals, irregulars) - The Local Group of Galaxies, The Virgo and Coma Cluster of galaxies - How images of distant galaxies allow us to look back in time - The Hubble Ultra Deep Field (HUDF) - The Doppler blueshift (Lectures 15-16) - Tracing stars, dust, gas via observations at different wavelengths (Lecture15-16). In next lectures, we will cover - Galaxy Classification. The Hubble Sequence - Mapping the Distance of Galaxies - Mapping the Visible Constituents of Galaxies: Stars, Gas, Dust - Understanding Galaxy Formation and Evolution - Galaxy Interactions: Nearby Galaxies, the Milky Way, Distant Galaxies - Mapping the Dark Matter in Galaxies and in the Universe - The Big Bang - Fates of our Universe and Dark Energy Galaxy Classification Galaxy: Collection of few times (108 to 1012) stars orbiting a common center and bound by gravity. Made of gas, stars, dust, dark matter. There are many types of galaxies and they can be classfiied according to different criteria. -
The Maunder Minimum and the Variable Sun-Earth Connection
The Maunder Minimum and the Variable Sun-Earth Connection (Front illustration: the Sun without spots, July 27, 1954) By Willie Wei-Hock Soon and Steven H. Yaskell To Soon Gim-Chuan, Chua Chiew-See, Pham Than (Lien+Van’s mother) and Ulla and Anna In Memory of Miriam Fuchs (baba Gil’s mother)---W.H.S. In Memory of Andrew Hoff---S.H.Y. To interrupt His Yellow Plan The Sun does not allow Caprices of the Atmosphere – And even when the Snow Heaves Balls of Specks, like Vicious Boy Directly in His Eye – Does not so much as turn His Head Busy with Majesty – ‘Tis His to stimulate the Earth And magnetize the Sea - And bind Astronomy, in place, Yet Any passing by Would deem Ourselves – the busier As the Minutest Bee That rides – emits a Thunder – A Bomb – to justify Emily Dickinson (poem 224. c. 1862) Since people are by nature poorly equipped to register any but short-term changes, it is not surprising that we fail to notice slower changes in either climate or the sun. John A. Eddy, The New Solar Physics (1977-78) Foreword By E. N. Parker In this time of global warming we are impelled by both the anticipated dire consequences and by scientific curiosity to investigate the factors that drive the climate. Climate has fluctuated strongly and abruptly in the past, with ice ages and interglacial warming as the long term extremes. Historical research in the last decades has shown short term climatic transients to be a frequent occurrence, often imposing disastrous hardship on the afflicted human populations. -
Highlights and Discoveries from the Chandra X-Ray Observatory1
Highlights and Discoveries from the Chandra X-ray Observatory1 H Tananbaum1, M C Weisskopf2, W Tucker1, B Wilkes1 and P Edmonds1 1Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138. 2 NASA/Marshall Space Flight Center, ZP12, 320 Sparkman Drive, Huntsville, AL 35805. Abstract. Within 40 years of the detection of the first extrasolar X-ray source in 1962, NASA’s Chandra X-ray Observatory has achieved an increase in sensitivity of 10 orders of magnitude, comparable to the gain in going from naked-eye observations to the most powerful optical telescopes over the past 400 years. Chandra is unique in its capabilities for producing sub-arcsecond X-ray images with 100-200 eV energy resolution for energies in the range 0.08<E<10 keV, locating X-ray sources to high precision, detecting extremely faint sources, and obtaining high resolution spectra of selected cosmic phenomena. The extended Chandra mission provides a long observing baseline with stable and well-calibrated instruments, enabling temporal studies over time-scales from milliseconds to years. In this report we present a selection of highlights that illustrate how observations using Chandra, sometimes alone, but often in conjunction with other telescopes, have deepened, and in some instances revolutionized, our understanding of topics as diverse as protoplanetary nebulae; massive stars; supernova explosions; pulsar wind nebulae; the superfluid interior of neutron stars; accretion flows around black holes; the growth of supermassive black holes and their role in the regulation of star formation and growth of galaxies; impacts of collisions, mergers, and feedback on growth and evolution of groups and clusters of galaxies; and properties of dark matter and dark energy.