Contents: Volume 73 Nos 1-2 February 2014 Volume 73 Nos 1 & 2 February 2014 CONTENTS OBITUARY – HALTON (CHIP) ARP .................................................................................... 1 OBITUARY – JOHN DOBSON ............................................................................................. 2 DESIGNING THE LARGEST RADIO TELESCOPE ON EARTH: THE FINAL RACE ......... 3 JACOB KARL ERNST HALM (1865-1944) ........................................................................ 14 THE SWALLOW PARK SUNDIALS ................................................................................... 24 COLLOQUIA AND SEMINARS .......................................................................................... 29 SKY DELIGHTS: TWO OF A KIND .................................................................................... 37 In this issue: HALTON (CHIP) ARP - JOHN DOBSON - SKA DESIGN JAKOB KARL ERNST HALM - SWALLOW PARK SUNDIALS SKY DELIGHTS (GEMINI) - COLLOQUIA EDITORIAL Mr Case Rijsdijk (Editor, MNASSA ) ASTRONOMICAL SOCIETY OF SOUTHERN AFRICA BOARD Mr Auke Slotegraaf (Editor, Sky Guide Africa South ) The Astronomical Society of Southern Africa (ASSA) was formed in 1922 by the amalgamation of Mr Christian Hettlage (Webmaster) the Cape Astronomical Association (founded 1912) and the Johannesburg Astronomical Association Prof M.W. Feast (Member, University of Cape Town) (founded 1918). It is a body consisting of both amateur and professional astronomers. Publications : The Society publishes its own electronic journal, the Monthly Notes of the Prof B. Warner (Member, University of Cape Town) Astronomical Society of Southern Africa (MNASSA) bi-monthly as well as its annual Sky Guide Africa MNASSA Mr Case Rijsdijk (Editor, MNASSA) South. PRODUCTION Dr Ian Glass (Assistant Editor) Membership : Membership of the Society is open to all. Potential members should consult the Society’s web page assa.saao.org.za for details. Joining is possible via one of the local Centres or as Mr Maciej Soltynski (Book Review Editor) a Country Member. Mr Willie Koorts (Consultant) Local Centres: Local Centres of the Society exist at Bloemfontein, Cape Town, Durban, Harare, EDITORIAL MNASSA, PO Box 9, Observatory 7935, South Africa Hermanus, Johannesburg, Pretoria and Sedgefield district (Garden Route Centre). Membership of any of these Centres automatically confers membership of the Society. ADDRESSES Email: [email protected] Sky & Telescope: Members may subscribe to Sky & Telescope at a significant discount (proof of Web page: http://mnassa.saao.ac.za membership is required). Please contact the Membership Secretary for details. MNASSA Download Page: www.mnassa.org.za Internet contact details: email: [email protected] Home Page: http://assa.saao.ac.za SUBSCRIPTIONS MNASSA is available for free download on the Council (2013-2014) Internet President Prof MJH Hoffman [email protected] ADVERTISING Advertisements may be placed in MNASSA at the Vice -President P De Villiers [email protected] Vice-President Dr I S Glass [email protected] following rates per insertion: full page R400, half page Members hip Secretary Pat Booth [email protected] R200, quarter page R100. Small advertisements R2 Hon. Treasurer Adv AJ Nel [email protected] per word. Enquiries should be sent to the editor at Hon. Secretary L Cross [email protected] Scholarships M G Soltynski [email protected] [email protected] Members C Stewart [email protected] CONTRIBUTIONS MNASSA mainly serves the Southern African G Els gels@randwater. co.za astronomical community. Articles may be submitted Bosman Olivier [email protected] by members of this community or by those with L. Labuscagne [email protected] Peter Dormehl [email protected] strong connections. Else they should deal with J Saunders [email protected] matters of direct interest to the community . MNASSA C Rijsdijk [email protected] is published on the first day of every second month Hon Auditor R G Glass (Horwath Zeller Karro) RonnieGlas [email protected] Directors of Sections and articles are due one month before the publication Shallow Sky D Blane [email protected] date. Deep Sky A Slotegraaf [email protected] RECOGNITION Articles from MNASSA appear in the NASA/ADS data Photometry, Spectroscopy Vacant system. Cosmology Astrophysics JFW de Bruyn [email protected] History C de Coning Siriusa@a bsamail.co.za Dark Sky J Smit [email protected] Imaging Gary Els [email protected] Front cover: Artist’s conception of one of the SKA dishes. Instrumentation Chris Stewart Chris .stewart@alcatel -lucent.com NGC 2331 Open 07h07m.2 +27°21’.7 8.5 18’ Cluster NGC 2365 Galaxy 07h22m.5 +22°05’.1 12.4 2.7’ x1.5’ STREICHER Asterism 07h23m.1 +29°16’.9 2.5 5.5’ mnassa 2 Vol 73 Nos 1 & 2 February 2014 NGC 2371 Planetary 07h25m.6 +29°29’.4 11.3 55” NGC 2372 Nebula Sh2-274 Emission 07h26m.2 +13°20’.7 13 615” Medusa Nebula Obituary – Halton (Chip) Arp NGC 2395 Open 07h27m.2 +13°35’.2 8 12’ Cluster Halton Christian Arp (March 21, 1927 – December 28, 2013) was one of NGC 2392 Planetary 07h29m.2 +20°54’.7 9.9 48” the most interesting and controversial astronomers of the last century. He Nebula was born in New York to an artist father. Following irregular schooling, he NGC 2420 Open 07h38m.5 +21°34’.4 8.3 10’ entered Harvard, where he graduated in 1949. He then went to Caltech as Cluster a graduate student and obtained his PhD in 1953. His thesis under Walter Baade was on a massive study of novae in M31 which was highly significant for the use of novae as distance indicators. In 1955-1957 he was attached to Indiana University as a Research Assistant. Much of this time was spent at the Royal Observatory, Cape of Good Hope, where he worked with the McClean telescope on photographic and photometric observations of the Small Magellanic Cloud, including its Cepheids. He also made observations of the globular clusters ω Cen and 47 Tuc. Michael Feast writes “Possibly Arp's most enduring work in SA was that on the colour-magnitude diagram and Cepheids in the young globular cluster NGC 1866. This was done in Pretoria [at the Radcliffe Observatory] where he spent a significant amount of time, some of it staying with me. The observational part was published with David Thackeray”. In 1957 he became a staff member of the Palomar Observatory, then by far the leading observational facility of the world. His best remembered contribution to astronomy is his “Atlas of Peculiar Galaxies”, ( Astrophys. _________________________________________________________________________________ 44 February 2014 J.Suppl . Ser. 14, 1-20. 1953). This led to widespread interest in galaxy brighter and with the help of an OIII filter the nebulosity of both lobes evolution and interactions. extends into a see-through haze. Soon afterwards Arp came to the conclusion that To end with a reference to another favourite, this time an asterism, none quasars were ejecta from galaxies and that their other than Streicher 2 , barely a half a redshift-derived motions were not of cosmological degree south-west of NGC 2371-2. origin but instead were the result of high velocities This asterism displays an exquisite caused by the ejection process. This view was not and dainty little grouping. It is quite accepted by the vast majority of quasar outstanding against the background researchers but was supported by a group of star field with the brighter “dissidents”, some of them quite famous magnitude 9.7 star towards the astronomers. As a result he ran into difficulties north. The first impression is a few with his colleagues at Palomar. stars from north-east to south-west in an uneven curve. Another short In 1983 Arp joined the Max Planck Institute for Astrophysics in Munich, string can be seen towards the east. and lived in that city for the rest of his life. When next you are lonely, take out A 1975 interview can be recommended for further information about his your close friend, the telescope, or a pair of binoculars, and bond with the interests and career (Interview with Dr Halton Arp”. By Paul Wright: twins this summer, while realising that they will always remain part of the www.aip.org/ohlist/4490.html ) [ISG (with input from MWF)]. great unknown. Obituary – John Dobson OBJECT TYPE RA DEC MAG SIZE John Lowry Dobson was born on September 14, 1915, in Beijing, China and NGC 2129 Open 06h01m.1 +23°17’.3 6.7 6’ died on January 15, 2014 in Burbank, California. He was arguably one of Cluster the best known amateur astronomers in the world for two reasons. Firstly, NGC 2158 Open 06h07m.5 +24°05’.8 8.6 5’ having made the night skies available to many people around the world Cluster with his simple telescope design, affectionately referred to nowadays as a NGC 2168 Open 06h08m.9 +24°20’.4 5.1 28’ “Dobbie”, and secondly for his founding of “Sidewalk Astronomy”. Messier 35 Cluster IC 443 Supernova 06h16m.9 +22°46’.5 12 40’ After taking a degree in chemistry at the University of California, Berkeley, Remnant in 1943, he joined the Vedanta Society Monastery where he became a NGC 2266 Open 06h43m.2 +26°58’.2 9.5 6’ Cluster _________________________________________________________________________________ _____________________________________________________________________________ 2 February 2014 mnassa 73 nos1-2 43 Another twosome shares half a monk of the Ramakrishna Order, his main role there, being to reconcile degree field of view only 1.3 astronomy with the teachings of Vedanta. He left the order in 1967 and degrees north of the founded the San Fransisco Sidewalk Astronomers with the aim of constellation Canis Minor. The popularizing astronomy. He also started teaching people how to build open cluster NGC 2395 displays a their own telescopes, the now well known Dobsonians: a simple, robust loose overall shape in a Newtonian reflecting telescope. triangular point towards the north, with faint stars scattered In 2005, the Smithsonian magazine listed John Dobson as among 35 randomly throughout. A very individuals who have made a major difference during the lifetime of that short string pointing south-west periodical.