Undergraduate Lecture Notes in Physics Mark Gallaway An Introduction to Observational Astrophysics Undergraduate Lecture Notes in Physics More information about this series at http://www.springer.com/series/8917 Undergraduate Lecture Notes in Physics (ULNP) publishes authoritative texts covering topics throughout pure and applied physics. Each title in the series is suitable as a basis for undergraduate instruction, typically containing prac- tice problems, worked examples, chapter summaries, and suggestions for further reading. ULNP titles must provide at least one of the following: An exceptionally clear and concise treatment of a standard undergraduate subject. A solid undergraduate-level introduction to a graduate, advanced, or nonstandard subject. A novel perspective or an unusual approach to teaching a subject. ULNP especially encourages new, original, and idiosyncratic approaches to physics teaching at the undergraduate level. The purpose of ULNP is to provide intriguing, absorbing books that will continue to be the reader’s preferred reference throughout their academic career. Series editors Neil Ashby Professor Emeritus, University of Colorado Boulder, CO, USA William Brantley Professor, Furman University, Greenville, SC, USA Matthew Deady Professor, Bard College, Annandale, NY, USA Michael Fowler Professor, University of Virginia, Charlottesville, VA, USA Morten Hjorth-Jensen Professor, University of Oslo, Norway Michael Inglis Professor, SUNY Suffolk County Community College, Selden, NY, USA Heinz Klose Professor Emeritus, Humboldt University Berlin, Germany Helmy Sherif Professor, University of Alberta, Edmonton, AB, Canada Mark Gallaway An Introduction to Observational Astrophysics 123 Mark Gallaway University of Hertfordshire Hockley, Essex, UK ISSN 2192-4791 ISSN 2192-4805 (electronic) Undergraduate Lecture Notes in Physics ISBN 978-3-319-23376-5 ISBN 978-3-319-23377-2 (eBook) DOI 10.1007/978-3-319-23377-2 Library of Congress Control Number: 2015950477 Springer Cham Heidelberg New York Dordrecht London © Springer International Publishing Switzerland 2016 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. Printed on acid-free paper Springer International Publishing AG Switzerland is part of Springer Science+Business Media (www. springer.com) This work is dedicated to the University of Hertfordshire’s Astronomy Public Outreach Team. Your professionalism, dedication and enthusiasm to educate and entertain the public with little/no reward are inspiring. Long may it continue. Acknowledgements I’d like to thank Dr David Murray and Dr Stuart Alder to whom I am truly indebted, for their work on the truly dull bits of editing. I would also like to thank all of my students both current and past. Without your youthful enthusiasm, my job would be a lot less interesting. I’d also like to thank the staff of the Physics, Mathematics and Astronomy Department of the University of Hertfordshire whose work many of the practicals herein we derived. Lastly, I’d like to thank my wife, Sarah, for leaving me alone when needed and supplying mugs of steaming tea late into the night. vii Contents 1 Introduction ................................................................. 1 1.1 The Reader............................................................ 1 1.2 Required Equipment and Software ................................. 2 1.3 How to Use This Book ............................................... 3 1.4 Introduction: Best Practice........................................... 4 2 The Nature of Light ........................................................ 7 2.1 Introduction........................................................... 7 2.2 The Quantum Nature of Light ....................................... 9 2.3 Measuring Light ...................................................... 11 2.4 The Magnitude Scale................................................. 12 2.5 Filters ................................................................. 15 2.6 Colour................................................................. 18 2.7 Polarisation ........................................................... 19 3 The Telescope ............................................................... 21 3.1 Telescopes ............................................................ 21 3.2 Mounts ................................................................ 27 3.3 Eyepieces and Additional Optics .................................... 29 3.4 Problems .............................................................. 31 4Time.......................................................................... 35 4.1 Introduction........................................................... 35 4.2 Solar Time ........................................................... 37 4.3 Julian Date ............................................................ 39 4.4 Sidereal Time ......................................................... 39 5 Spheres and Coordinates .................................................. 43 5.1 Introduction .......................................................... 43 5.2 Altitude and Azimuth ................................................ 44 5.3 Equatorial ............................................................. 46 5.4 Galactic Coordinates ................................................. 48 ix x Contents 5.5 Other Minor System.................................................. 49 5.6 Spherical Geometry .................................................. 49 6 Catalogues and Constellations ............................................ 53 6.1 Introduction........................................................... 53 6.2 Constellations, Asterisms and Bright Stars ......................... 53 6.3 Catalogues ............................................................ 56 6.4 Databases ............................................................. 63 7 The Astronomical Detector ................................................ 67 7.1 The Detector .......................................................... 67 7.2 Noise and Uncertainty in CCD ...................................... 69 7.3 Binning and Sub-framing ............................................ 72 7.4 The FITS File Format ................................................ 73 7.5 Calibration Frames ................................................... 74 7.5.1 Practical 1: The Bias and Dark Frames .................... 78 7.5.2 Practical 2: Flat Frames .................................... 80 7.6 Linearity of CCD ..................................................... 83 7.6.1 Practical 3: Measuring CCD Linearity .................... 84 7.7 Bad Pixels and Cosmic Rays ........................................ 85 7.7.1 Practical 4: Bad Pixels and Cosmic Rays ................. 86 7.8 Gain ................................................................... 86 7.8.1 Practical 5: Measuring Camera Gain ...................... 87 7.9 Saturation, Blooming and Other Effects ............................ 88 8 Imaging ...................................................................... 91 8.1 Introduction........................................................... 91 8.2 Planning .............................................................. 92 8.3 In Dome Pre-observation Preparation ............................... 94 8.3.1 Calibration Frames ......................................... 94 8.3.2 Pointing ..................................................... 97 8.3.3 Focusing..................................................... 98 8.4 Guiding ............................................................... 100 8.5 Target Specific Problems............................................. 101 8.5.1 Imaging Open Clusters ..................................... 102 8.5.2 Imaging Globular Clusters ................................. 105 8.5.3 Imaging Galaxies ........................................... 107 8.5.4 Planetary and Emission and Dark Nebulae ................ 108 8.6 Stacking and Dithering............................................... 110 8.7 Practical 6: The Messier Marathon .................................. 111 8.7.1 Aims......................................................... 111 8.7.2 Planning ..................................................... 111 8.7.3 Getting Ready............................................... 112 8.7.4 Imaging ..................................................... 113 8.7.5 Shutdown ................................................... 114 Contents xi 8.7.6 Post Imaging ...............................................