THE HANDBOOK OF THE BRITISH ASTRONOMICAL ASSOCIATION 2020 2019 October ISSN 0068–130–X CONTENTS PREFACE . 2 HIGHLIGHTS FOR 2020 . 3 SKY DIARY . .. 4–5 CALENDAR 2020 . 6 SUN . 7–9 ECLIPSES . 10–17 APPEARANCE OF PLANETS . 18 VISIBILITY OF PLANETS . 19 RISING AND SETTING OF THE PLANETS IN LATITUDES 52°N AND 35°S . 20–21 PLANETS – Explanation of Tables . 22 ELEMENTS OF PLANETARY ORBITS . 23 MERCURY . 24–25 VENUS . 26 EARTH . 27 MOON . 27 LUNAR LIBRATION . 28 MOONRISE AND MOONSET . 30–33 SUN’S SELENOGRAPHIC COLONGITUDE . 34 LUNAR OCCULTATIONS . 35–41 GRAZING LUNAR OCCULTATIONS . 42–43 MARS . 44–45 ASTEROIDS . 46 ASTEROID EPHEMERIDES . 47–51 ASTEROID OCCULTATIONS . 52–55 ASTEROIDS: FAVOURABLE OBSERVING OPPORTUNITIES . 56–58 NEO CLOSE APPROACHES TO EARTH . 59 JUPITER . .. 60–64 SATELLITES OF JUPITER . .. 64–68 JUPITER ECLIPSES, OCCULTATIONS AND TRANSITS . 69–78 SATURN . 79–82 SATELLITES OF SATURN . 83–86 URANUS . 87 NEPTUNE . 88 TRANS–NEPTUNIAN & SCATTERED–DISK OBJECTS . 89 DWARF PLANETS . 90–93 COMETS . 94–98 METEOR DIARY . 99–101 VARIABLE STARS (RZ Cassiopeiae; Algol; RS Canum Venaticorum) . 102–103 MIRA STARS . 104 VARIABLE STAR OF THE YEAR (SV Sagittae) . 105–107 EPHEMERIDES OF VISUAL BINARY STARS . 108–109 BRIGHT STARS . 110 ACTIVE GALAXIES . 111 TIME . 112–113 ASTRONOMICAL AND PHYSICAL CONSTANTS . 114–115 GREEK ALPHABET . 115 ACKNOWLEDGMENTS / ERRATA . 116 Front Cover: Comet 46P/Wirtanen, taken 2018 December 8 by Martin Mobberley. Equipment – Televue NP127, FLI ProLine 16803 CCD British Astronomical Association HANDBOOK FOR 2020 NINETY–NINTH YEAR OF PUBLICATION © British Astronomical Association BURLINGTON HOUSE, PICCADILLY, LONDON, W1J 0DU Telephone 020 7734 4145 PREFACE Welcome to the 99th Handbook of the British Astronomical Association. The Handbook highlights forthcoming astronomical events for the year, but there are always events that can be missed, or are entirely unpredictable, like comets, asteroid close approaches, aurorae, etc. Make sure you watch the BAA’s website for the latest news. Also, make sure you are receiving the new email newsletters by keeping your email up to date with the BAA office. Once again we would also encourage everyone to join their local astronomical society to try equipment, talk to like–minded people, and to give and receive help. It can take a long time to choose the right equipment and learn how to use it, so make the most of your local society. The BAA’s Sections can help too. Contact the Section Directors, who will be pleased to help. You may also like to consider getting involved with the annual events organised as part of World Space Week (Oct. 4–10). This is an international celebration of all things SPACE and focuses on science and technology and its role in the past, present and future of mankind. World Space Week currently consists of space education and outreach events held by space agencies, aerospace companies, schools, planetaria, museums, and astronomy clubs around the world. (http://www.worldspaceweek.org/). Unfortunately we are restricted by the number of pages that we can include in the Handbook. This does mean that some things will have to be left out. This edition we have had to remove the Internet Resources pages to make room for more eclipse/transit pages. However, the Computing Section does publish all additional data on the section website (http://britastro.org/computing). This includes both Comet charts and Asteroid Oppositions and Appulses. Members may also like to know that the Computing Section provides the data for the Royal Astronomical Society’s Diary. Finally, we must thank all the contributors to the Handbook. You will find them acknowledged on page 116. Contact details for many of these can be found at the back of every Journal. Alternatively, email the Director, Steve Harvey (address below) and messages can be forwarded to those concerned. Clear skies for 2020 ! Steve Harvey FRAS Director, Computing Section Email: [email protected] 2019 August 2 Preface BAA Handbook 2020 HIGHLIGHTS FOR 2020 The following events during 2020 are worthy of note: Sun and Moon: There will be six eclipses (two of the Sun and four of the Moon). All four lunar eclipses are quite observationally challenging penumbral eclipses. An annular solar eclipse occurs June 21 and a total solar eclipse shall be visble in South America, December 14. Planets, Dwarf Planets and Asteroids: Mercury is best seen around the time of greatest elongation. For the mornings, this will be March 24, July 22 and November 10. Whilst for evening apparitions it will be February 10, June 04 and October 01. Venus is an evening object for the first half of the year and a morning object for the second half of the year. It is at Greatest Western Elongation of 46 degrees from the Sun on March 24 and again August 12. Mars is visible as an all–night object until October, after which it becomes a morning object again. Meteors: Among the meteor showers, the most favourable are: the Lyrids (April), Leonids (November) and the Geminids (December). Also favourable are: Quadrantids, Perseids, Kappa Cygnids, Orionids and the Ursids. Comets: Comet C/2017 T2 (PANSTARRS) is expected to reach peak brightness in May at +7, whilst 88P/ Howell is predicted to reach +8 in September. It is also worth paying attention to Comet 29P/Sch- wassmann–Wachmann, given that it outbursts several times each year. Refer to the BAA Comet Section for latest info : http://britastro.org/comet Space Probes and Artificial Satellites: NASA plans to launch the Mars 2020 rover, whilst ESA and Roscosmos intend to launch the ExoMars lander and rover. China is to begin construction of a large modular space station with the launch of the Tianhe Core Cabin Module. NASA will carry out the maiden launch of the Space Launch System and SpaceX will begin orbital testing of its fully reusable two–stage–to–orbit vehi- cle BFR. In early 2020 following the launch of the first 300+ satellites, the OneWeb constellation is expected to become operational, whilst SpaceX expects to begin operation of its Starlink system, with about 720 satellites launched by the end of the year. Positional predictions for the ISS and other bright satellites can be found for any geographic loca- tion at: http://www.heavens–above.com Highlights by date: Jan. 10 Penumbral lunar eclipse visible from Europe, Africa, Asia and Australia. Mar. 18 Jupiter, Mars and Moon conjunction 05:00UT 20 The vernal equinox occurs in the northern hemisphere at 03:50 UT Apr. 22 Lyrid meteor shower Jun. 5 Penumbral lunar eclipse visible from Europe, Africa, Asia and Australia 20 The summer solstice occurs in the northern hemisphere at 21:44 UT 21 An annular solar eclipse visible from central East Africa and southern Asia. Jul. 5 Penumbral lunar eclipse visible from.