Messenger-No117.Pdf
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
CENTAURI II Benutzerhandbuch
CENTAURI II Benutzerhandbuch SW-Version ab 3.1.0.73 MAYAH, CENTAURI, FLASHCAST sind eingetragene Warenzeichen. Alle anderen verwendeten Warenzeichen werden hiermit anerkannt. CENTAURI II Benutzerhandbuch ab SW 3.1.0.73 Bestell-Nr. CIIUM001 Stand 11/2005 (c) Copyright by MAYAH Communications GmbH Die Vervielfältigung des vorliegenden Handbuches, sowie der darin besprochenen Dokumentationen aus dem Internet, auch nur auszugsweise, ist nur mit ausdrücklicher schriftlicher Genehmigung der MAYAH Communications GmbH erlaubt. 1 Einführung ........................................................................................................... 1 1.1 Vorwort......................................................................................................... 1 1.2 Einbau / Installation ...................................................................................... 2 1.3 Lieferumfang ................................................................................................ 2 1.4 Umgebungs- / Betriebsbedingung................................................................ 2 1.5 Anschlüsse................................................................................................... 3 2 Verbindungsaufbau ............................................................................................. 4 2.1 ISDN Verbindungen mit dem Centauri II ...................................................... 4 2.1.1 FlashCast Technologie und Audiocodec Kategorien............................. 4 2.1.2 Wie bekomme ich eine synchronisierte Verbindung -
Hubble Space Telescope Observer’S Guide Winter 2021
HUBBLE SPACE TELESCOPE OBSERVER’S GUIDE WINTER 2021 In 2021, the Hubble Space Telescope will celebrate 31 years in operation as a powerful observatory probing the astrophysics of the cosmos from Solar system studies to the high-redshift universe. The high-resolution imaging capability of HST spanning the IR, optical, and UV, coupled with spectroscopic capability will remain invaluable through the middle of the upcoming decade. HST coupled with JWST will enable new innovative science and be will be key for multi-messenger investigations. Key Science Threads • Properties of the huge variety of exo-planetary systems: compositions and inventories, compositions and characteristics of their planets • Probing the stellar and galactic evolution across the universe: pushing closer to the beginning of galaxy formation and preparing for coordinated JWST observations • Exploring clues as to the nature of dark energy ACS SBC absolute re-calibration (Cycle 27) reveals 30% greater • Probing the effect of dark matter on the evolution sensitivity than previously understood. More information at of galaxies http://www.stsci.edu/contents/news/acs-stans/acs-stan- • Quantifying the types and astrophysics of black holes october-2019 of over 7 orders of magnitude in size WFC3 offers high resolution imaging in many bands ranging from • Tracing the distribution of chemicals of life in 2000 to 17000 Angstroms, as well as spectroscopic capability in the universe the near ultraviolet and infrared. Many different modes are available for high precision photometry, astrometry, spectroscopy, mapping • Investigating phenomena and possible sites for and more. robotic and human exploration within our Solar System COS COS2025 initiative retains full science capability of COS/FUV out to 2025 (http://www.stsci.edu/hst/cos/cos2025). -
JUICE Red Book
ESA/SRE(2014)1 September 2014 JUICE JUpiter ICy moons Explorer Exploring the emergence of habitable worlds around gas giants Definition Study Report European Space Agency 1 This page left intentionally blank 2 Mission Description Jupiter Icy Moons Explorer Key science goals The emergence of habitable worlds around gas giants Characterise Ganymede, Europa and Callisto as planetary objects and potential habitats Explore the Jupiter system as an archetype for gas giants Payload Ten instruments Laser Altimeter Radio Science Experiment Ice Penetrating Radar Visible-Infrared Hyperspectral Imaging Spectrometer Ultraviolet Imaging Spectrograph Imaging System Magnetometer Particle Package Submillimetre Wave Instrument Radio and Plasma Wave Instrument Overall mission profile 06/2022 - Launch by Ariane-5 ECA + EVEE Cruise 01/2030 - Jupiter orbit insertion Jupiter tour Transfer to Callisto (11 months) Europa phase: 2 Europa and 3 Callisto flybys (1 month) Jupiter High Latitude Phase: 9 Callisto flybys (9 months) Transfer to Ganymede (11 months) 09/2032 – Ganymede orbit insertion Ganymede tour Elliptical and high altitude circular phases (5 months) Low altitude (500 km) circular orbit (4 months) 06/2033 – End of nominal mission Spacecraft 3-axis stabilised Power: solar panels: ~900 W HGA: ~3 m, body fixed X and Ka bands Downlink ≥ 1.4 Gbit/day High Δv capability (2700 m/s) Radiation tolerance: 50 krad at equipment level Dry mass: ~1800 kg Ground TM stations ESTRAC network Key mission drivers Radiation tolerance and technology Power budget and solar arrays challenges Mass budget Responsibilities ESA: manufacturing, launch, operations of the spacecraft and data archiving PI Teams: science payload provision, operations, and data analysis 3 Foreword The JUICE (JUpiter ICy moon Explorer) mission, selected by ESA in May 2012 to be the first large mission within the Cosmic Vision Program 2015–2025, will provide the most comprehensive exploration to date of the Jovian system in all its complexity, with particular emphasis on Ganymede as a planetary body and potential habitat. -
Pos(Westerbork)002 Historical Introduction Historical S 4.0 International License (CC BY-NC-ND 4.0)
Historical Introduction PoS(Westerbork)002 Richard Strom ASTRON Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The Netherlands E-mail: [email protected] 50 Years Westerbork Radio Observatory, A Continuing Journey to Discoveries and Innovations Richard Strom, Arnold van Ardenne, Steve Torchinsky (eds) Published with permission of the Netherlands Institute for Radio Astronomy (ASTRON) under the terms of the Creative CommonsAttribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). Chapter 1 Historical introduction Richard Strom* rom the English longbows at the battle of Crécy (1346) to Winston Chur- chill’s world war I mobilized cannon (its true identity hidden behind the Fpseudonym “[water] tank”), warfare has always pushed technological innovation to new fronts. The second world war (WWII) was no exception. It gave us technology ranging from the dynamo-powered flashlight (a Philips invention) to jet engines, and space-capable rockets (Germany’s V2), not to mention (in a completely different realm) the mass production of Penicillin. In fact, it could be argued that WWII inventions marked the inception of the modern technological era1. In the field of electronics, the war led to innovations such as radio navigation, aircraft landing systems, and radar. It was these developments which were to * ASTRON, Univer- sity of Amsterdam, have a revolutionary impact on astronomy, initially in Britain, Australia and the The Netherlands United States. But the story begins in the US, with the electronics of the 1920s and ‘30s. Figure 1. Karl G. Jansky (c. 1933) Around 1930, there was increasing interest in the use of radio frequencies for communication. One of the main players, the Bell Telephone Laboratories in New Jersey, asked their research engineer, Karl Jansky (Figure 1), to investigate the inter- ference environment in the “short-wave” band around 20 MHz. -
• Context. Young Exoplanetary Systems with Ages 600 Ma (I.E. Hyades-Like Or Younger) Can Provide Constraints on the Time Scal
• Context. Young exoplanetary systems with ages 600 Ma (i.e. Hyades-like or younger) can provide constraints on the time scale and mechanism of planet formation, and on the planet evolution (orbital migration, late heavy bombardment...). Apart from the very young “planet” candidates found by direct imaging (around e.g. HR 8799, 2M1207-39 or AB Pic), some young planet candidates have been found with the radial velocity method, such as HD 70573b (Setiawan et al. 2007) in the Hercules-Lyra subgroup of the Local Association or the controversial TW Hya b (Setiawan et al. 2008). [left, top: histogram of planet ages, from Joergens (2009, ASTROCAM school)] • Aims. We search for bright Hipparcos stars with radial-velocity planets that are member candidates in young moving groups (Montes et al. 2001), such as the Hyades, IC 2391, Ursa Majoris and Castor superclusters and the Local Association ( = 100-600 Ma), and very young moving groups like Pictoris or TW Hydrae ( < 100 Ma). Generally, these stars are discarded from accurate radial-velocity searches based on activity indicators, but there might be young stars that passed the rejection filter (e.g. HD 81040, ~ 700 Ma; Sozzetti et al. 2006). • Methods. On 2009 Sep 1, the Extrasolar Planets Encyclopaedia (exoplanet.eu) tabulated 346 planet candidates in 295 planetary systems detected by radial velocity (35 multiple planet systems). Of them, 228 have Hipparcos stars as host stars. We have computed Galactocentric space velocities UVW derived from star coordinates, proper motions, and parallactic distances (from van Leeuwen 2007), and systemic radial velocities, Vr (), from a number of works, including Nordström et al. -
3. Extrasolar Planets How Planets Were Discovered in the Solar System
3. Extrasolar Planets How planets were discovered in the solar system Many are bright enough to see with the naked eye! More distant planets are fainter (scattered light flux - 4 ∝ apl ) and were discovered by imaging the sky at different times and looking for fast-moving things which must be relatively nearby (Kuiper belt objects and asteroids etc are still discovered in this way) but People are still some (e.g., Neptune) were predicted based on searching for planet X perturbations to the orbit of known planets in the solar system (e.g., Gaudi & Bloom Problem for detecting planets is that there is a lot of 2005 say Gaia will area of sky the planets could be hiding in, so narrow detect 1M out to searches to ecliptic planet (although tenth planet J 2000AU) has i=450) and use knowledge of dynamics to predict planet locations Can we do the same thing in extra-solar systems? Extra-solar planet Not quite so easily! The geometry of the problem is SS planet different, which means that: Earth • you don’t get a continuous motion across the sky • although we have narrowed down the region where the planet can be • but the planet is very far away and so it is faint, scattered light flux -2 -2 ∝ d* apl where d* is measured in pc (1pc=206,265AU) • which is compounded by the fact that it is close to a very bright star So how do we detect extrasolar planets? Mostly using indirect detection techniques: Effect on motion of parent star • Astrometric wobble • Timing shifts • Doppler wobble method Effect on flux we detect from parent star • Planetary transits -
Naming the Extrasolar Planets
Naming the extrasolar planets W. Lyra Max Planck Institute for Astronomy, K¨onigstuhl 17, 69177, Heidelberg, Germany [email protected] Abstract and OGLE-TR-182 b, which does not help educators convey the message that these planets are quite similar to Jupiter. Extrasolar planets are not named and are referred to only In stark contrast, the sentence“planet Apollo is a gas giant by their assigned scientific designation. The reason given like Jupiter” is heavily - yet invisibly - coated with Coper- by the IAU to not name the planets is that it is consid- nicanism. ered impractical as planets are expected to be common. I One reason given by the IAU for not considering naming advance some reasons as to why this logic is flawed, and sug- the extrasolar planets is that it is a task deemed impractical. gest names for the 403 extrasolar planet candidates known One source is quoted as having said “if planets are found to as of Oct 2009. The names follow a scheme of association occur very frequently in the Universe, a system of individual with the constellation that the host star pertains to, and names for planets might well rapidly be found equally im- therefore are mostly drawn from Roman-Greek mythology. practicable as it is for stars, as planet discoveries progress.” Other mythologies may also be used given that a suitable 1. This leads to a second argument. It is indeed impractical association is established. to name all stars. But some stars are named nonetheless. In fact, all other classes of astronomical bodies are named. -
Exploration of the Moon
Exploration of the Moon The physical exploration of the Moon began when Luna 2, a space probe launched by the Soviet Union, made an impact on the surface of the Moon on September 14, 1959. Prior to that the only available means of exploration had been observation from Earth. The invention of the optical telescope brought about the first leap in the quality of lunar observations. Galileo Galilei is generally credited as the first person to use a telescope for astronomical purposes; having made his own telescope in 1609, the mountains and craters on the lunar surface were among his first observations using it. NASA's Apollo program was the first, and to date only, mission to successfully land humans on the Moon, which it did six times. The first landing took place in 1969, when astronauts placed scientific instruments and returnedlunar samples to Earth. Apollo 12 Lunar Module Intrepid prepares to descend towards the surface of the Moon. NASA photo. Contents Early history Space race Recent exploration Plans Past and future lunar missions See also References External links Early history The ancient Greek philosopher Anaxagoras (d. 428 BC) reasoned that the Sun and Moon were both giant spherical rocks, and that the latter reflected the light of the former. His non-religious view of the heavens was one cause for his imprisonment and eventual exile.[1] In his little book On the Face in the Moon's Orb, Plutarch suggested that the Moon had deep recesses in which the light of the Sun did not reach and that the spots are nothing but the shadows of rivers or deep chasms. -
Radio Astronomy
Theme 8: Beyond the Visible I: radio astronomy Until the turn of the 17th century, astronomical observations relied on the naked eye. For 250 years after this, although astronomical instrumentation made great strides, the radiation being detected was still essentially confined to visible light (Herschel discovered infrared radiation in 1800, and the advent of photography opened up the near ultraviolet, but these had little practical significance). This changed dramatically in the mid-20th century with the advent of radio astronomy. 8.1 Early work: Jansky and Reber The atmosphere is transparent to visible light, but opaque to many other wavelengths. The only other clear “window” of transparency lies in the radio region, between 1 mm and 30 m wavelength. One might expect that the astronomical community would deliberately plan to explore this region, but in fact radio astronomy was born almost accidentally, with little if any involvement of professional astronomers. Karl Jansky (1905−50) was a radio engineer at Bell Telephone. In 1932, while studying the cause of interference on the transatlantic radio-telephone link, he discovered that part of the interference had a periodicity of one sidereal day (23h 56m), and must therefore be coming from an extraterrestrial source. By considering the time at which the interference occurred, Jansky identified the source as the Milky Way. This interesting finding was completely ignored by professional astronomers, and was followed up only by the radio engineer and amateur astronomer Grote Reber (1911−2002). Reber built a modern-looking paraboloid antenna and constructed maps of the radio sky, which also failed to attract significant professional attention. -
Cryogenics in Space
— 37 — Cryogenics in space Nicola RandoI Abstract Cryogenics plays a key role on board space-science missions, with a range of applications, mainly in the domain of astrophysics. Indeed a tremendous progress has been achieved over the last 20 years in cryogenics, with enhanced reliability and simpler operations, thus matching the needs of advanced focal-plane detectors and complex science instrumentation. In this article we provide an overview of recent applications of cryogenics in space, with specific emphasis on science missions. The overview includes an analysis of the impact of cryogenics on the spacecraft system design and of the main technical solutions presently adopted. Critical technology developments and programmatic aspects are also addressed, including specific needs of future science missions and lessons learnt from recent programmes. Introduction H. Kamerlingh-Onnes liquefied 4He for the first time in 1908 and discovered superconductivity in 1911. About 100 years after such achievements (Pobell 1996), cryogenics plays a key role on board space-science missions, providing the environ- ment required to perform highly sensitive measurements by suppressing the thermal background radiation and allowing advantage to be taken of the performance of cryogenic detectors. In the last 20 years several spacecraft have been equipped with cryogenic in- strumentation. Among such missions we should mention IRAS (launched in 1983), ESA’s ISO (launched in 1995) (Kessler et al 1996) and, more recently, NASA’s Spitzer (formerly SIRTF, launched in 2006) (Werner 2005) and the Japanese mis- sion Akari (IR astronomy mission launched in 2006) (Shibai 2007). New missions involving cryogenics are the ESA missions Planck (dedicated to the mapping of the cosmic background radiation) and Herschel (far infrared and sub-millimetre observatory), carrying instruments operating at temperatures of 0.1 K and 0.3 K, respectively (Crone et al 2006). -
Desert Skies Since 1954 Spring 2015 Volume LXI, Issue 1
Tucson Amateur Astronomy Association Observing our Desert Skies since 1954 Spring 2015 Volume LXI, Issue 1 Inside this issue: The Tadpoles in IC410 President’s 2 Letter Outreach 3, 5 New RideShare 7 Program Observing & 8 - 11 Imaging Featured 12, 14 Articles Classifieds 7 Sponsors 7 Contacts 15 Take Note! Science Fair and Book Festival Reports TAAA member Howard Bower photographed IC 410 which is found in Auriga TAAA RideShare Program using a Telescope Engineering Company TEC 140 ED apochromat refractor with Announced a field flattener resulting in f/7.4. This is a narrow band image with 34 exposures in Hydrogen Alpha (30 minutes each), 34 exposures in Oxygen III (binned 2x2 at Jupiter Opposition 2015 15 minutes each), and 34 exposures in Sulphur II (binned 2x2 at 15 minutes each). Report IC410 is a faint emission nebula surrounding the star cluster NGC 1893. At the Constellation of the top left of the nebula are two objects known as “The Tadpoles”. These are likely Season—Centaurus areas of stellar formation. Each tadpole is about 10 light years long. This object is at a distance of about 12,000 light years. © 2013 Howard Bower. Used by New Items in the Classifieds permission. Desert Skies Page 2 Volume LXI, Issue 1 From Our President As I reviewed the March Bulletin it was really heartwarming to see all of the activities in which we are involved. It takes a lot of Our mission is to provide opportunities for members dedication and hard work to put this all together and make it and the public to share the joy and excitement of work.. -
The Odin Orbital Observatory
A&A 402, L21–L25 (2003) Astronomy DOI: 10.1051/0004-6361:20030334 & c ESO 2003 Astrophysics The Odin orbital observatory H. L. Nordh1,F.vonSch´eele2, U. Frisk2, K. Ahola3,R.S.Booth4,P.J.Encrenaz5, Å. Hjalmarson4, D. Kendall6, E. Kyr¨ol¨a7,S.Kwok8, A. Lecacheux5, G. Leppelmeier7, E. J. Llewellyn9, K. Mattila10,G.M´egie11, D. Murtagh12, M. Rougeron13, and G. Witt14 1 Swedish National Space Board, Box 4006, 171 04 Solna, Sweden Letter to the Editor 2 Swedish Space Corporation, PO Box 4207, 171 04 Solna, Sweden 3 National Technology Agency of Finland (TEKES), Kyllikkiporten 2, PB 69, 00101 Helsinki, Finland 4 Onsala Space Observatory, Chalmers University of Technology, 439 92, Onsala, Sweden 5 Observatoire de Paris, 61 Av. de l’Observatoire, 75014 Paris, France 6 Canadian Space Agency, PO Box 7275, Ottawa, Ontario K1L 8E3, Canada 7 Finnish Meteorological Institute, PO Box 503, 00101 Helsinki, Finland 8 Department of Physics and Astronomy, University of Calgary, Calgary, ABT 2N 1N4, Canada 9 Department of Physics and Engineering Physics, 116 Science Place, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada 10 Observatory, PO Box 14, University of Helsinki, 00014 Helsinki, Finland 11 Institut Pierre Simon Laplace, CNRS-Universit´e Paris 6, 4 place Jussieu, 75252 Paris Cedex 05, France 12 Global Environmental Measurements Group, Department of Radio and Space Science, Chalmers, 412 96 G¨oteborg, Sweden 13 Centre National d’Etudes´ Spatiales, Centre Spatial de Toulouse, 18 avenue Edouard´ Belin, 31401 Toulouse Cedex 4, France 14 Department of Meteorology, Stockholm University, 106 91 Stockholm, Sweden Received 6 December 2002 / Accepted 17 February 2003 Abstract.