National Aeronautics and Space Administration A Guide to Smartphone Astrophotography National Aeronautics and Space Administration A Guide to Smartphone Astrophotography A Guide to Smartphone Astrophotography Dr. Sten Odenwald NASA Space Science Education Consortium Goddard Space Flight Center Greenbelt, Maryland Cover designs and editing by Abbey Interrante Cover illustrations Front: Aurora (Elizabeth Macdonald), moon (Spencer Collins), star trails (Donald Noor), Orion nebula (Christian Harris), solar eclipse (Christopher Jones), Milky Way (Shun-Chia Yang), satellite streaks (Stanislav Kaniansky),sunspot (Michael Seeboerger-Weichselbaum),sun dogs (Billy Heather). Back: Milky Way (Gabriel Clark) Two front cover designs are provided with this book. To conserve toner, begin document printing with the second cover. This product is supported by NASA under cooperative agreement number NNH15ZDA004C. [1] Table of Contents Introduction.................................................................................................................................................... 5 How to use this book ..................................................................................................................................... 9 1.0 Light Pollution ....................................................................................................................................... 12 2.0 Cameras ................................................................................................................................................. 15 2.1 Basic Definitions ............................................................................................................................... 15 2.2 Spectral Response .............................................................................................................................. 16 2.3 Camera Sensors and Pixels - How They Work ................................................................................. 16 2.4 The basic camera mechanism and controllable factors ..................................................................... 21 2.4.1 Aperture size ............................................................................................................................... 21 2.4.2 The F-stop ................................................................................................................................... 23 2.4.3 Exposure speed ........................................................................................................................... 26 2.4.4 ISO .............................................................................................................................................. 28 2.5 Sources of Noise ................................................................................................................................ 30 3.0 The art of calibration and why it works ................................................................................................. 31 3.1 But First A bit of Statistics ................................................................................................................ 31 3.2 Gain Correction and Flat Fielding ..................................................................................................... 33 3.3 Bias Frames ....................................................................................................................................... 35 3.4 Dark Current ...................................................................................................................................... 35 4.0 Which smartphone camera should I use? .............................................................................................. 41 5.0 Software ................................................................................................................................................ 45 5.1 The Native Camera ............................................................................................................................ 45 5.1.1 Manual Mode .............................................................................................................................. 45 5.1.2 Low-Light Photography.............................................................................................................. 46 5.2 Third Party Apps................................................................................................................................ 49 5.3 Stacking and Adjusting apps ............................................................................................................. 51 5.4 Intervalometers .................................................................................................................................. 52 6.0 External Equipment ............................................................................................................................... 52 6.1 Telephoto Lenses ............................................................................................................................... 52 [2] 6.2 Binoculars .......................................................................................................................................... 57 6.3 Telescopes .......................................................................................................................................... 58 7.0 Star field photography ........................................................................................................................... 60 7.1 Stellar Magnitudes ............................................................................................................................. 60 7.2 One-Shot Wonders. ............................................................................................................................ 61 7.3 With a tripod – Now that’s more like it ............................................................................................. 62 7.4 Star Trails........................................................................................................................................... 71 8.0 Photographing the Moon ....................................................................................................................... 75 9.0 Photographing the Planets ..................................................................................................................... 80 10.0 Photographing Deep Sky Objects ........................................................................................................ 84 10.1 The Orion Nebula – Messier 42 ....................................................................................................... 85 10.2 The Pleiades ..................................................................................................................................... 88 10.3 Other Star Clusters ........................................................................................................................... 90 10.4 Other Nebulae .................................................................................................................................. 94 10.5 Galaxies ........................................................................................................................................... 94 10.6 Supernova ...................................................................................................................................... 103 11.0 Photographing the Sun ....................................................................................................................... 104 11.1 Solar Eclipse Photography ............................................................................................................. 107 11.2 Lunar eclipses ................................................................................................................................ 112 11.3 Extra-solar Photography ................................................................................................................ 113 11.4 Solar surface photography with telescopic imaging ...................................................................... 116 11.4.1 Broadband Filters.................................................................................................................... 117 11.4.2 Narrow-band Filters ................................................................................................................ 121 12.0 Meteors and Comets .......................................................................................................................... 122 13.0 Photographing Artificial Satellites .................................................................................................... 127 13.1 The International Space Station ..................................................................................................... 128 13.2 Starlink Satellites ........................................................................................................................... 131 14.0 Photographing the Aurora Borealis ................................................................................................... 137 14.1 Aurora Colors and Forms .............................................................................................................. 137 14.2 Space Weather ..............................................................................................................................