British Astronomical Association VARIABLE STAR SECTION CIRCULAR No 161, September 2014 Contents Chi Cygni Chart - J Toone ....................................................... inside front cover From the Director - R. Pickard ........................................................................... 3 Thomas Lloyd Evans - R. Pickard ..................................................................... 3 Variable Star Section Meeting, York (part 1) - M. Taylor .................................. 5 Hiroaki Narumi - J. Toone ................................................................................ 10 BAA VSS Facebook Update - T. Markham .................................................... 14 Recent Measurements of HR Del - D. Boyd .................................................. 15 Chi Cygni - The Faintest Maximum - J. Toone ............................................... 18 Observing Ecliptic Variables Near Conjunction - T. Markham ........................ 20 Gaps in Historical Light Curves - T. Markham ............................................... 22 Examples of Light Curves with Gaps in Data .......................................... 22 - 33 Binocular Programme - M. Taylor ................................................................... 33 Eclipsing Binary Predictions – Where to Find Them - D. Loughney .............. 34 Charges for Section Publications .............................................. inside back cover Guidelines for Contributing to the Circular .............................. inside back cover ISSN 0267-9272 Office: Burlington House, Piccadilly, London, W1J 0DU CHI CYGNI JOHN TOONE FROM THE DIRECTOR ROGER PICKARD VSS Meeting 2014 The recent VSS Meeting at York was a great success and I hope that those of you unable to attend have enjoyed browsing the presentations available at: http://www.britastro.org/vss/York_June21_2014.htm. Missing Data I wrote in the last Circular that there were many gaps in the data for a large number of the stars on our Programmes. In order to fill in some of these gaps I am very grateful to Tony Markham for producing the graphs shown in this Issue, and the explanatory text (see “Gaps in Historical Light Curves”). All of the graphs and text have also been placed on the website. So, if you think some of your data is missing and you still have it please contact the me so that we can arrange keying it in. Binocular Programme You will notice that we are no longer publishing the full list of Binocular Programme Stars which we have been doing for the last few Circulars. All of the information is on the web pages after all, but for those of you who prefer it in paper format please contact either Melvyn Taylor < [email protected] > or myself < [email protected] >. * * * THOMAS LLOYD-EVANS (1940-2014) Tom Lloyd-Evans passed away quite suddenly on 12 June 2014 at the age of 73. Tom joined the BAA in 1956 after becoming interested in astronomy following encouragement from both parents and teachers alike. Along with his younger brother and during vacations from school, he built wooden box cameras with ex- WD Aero-Ektar lenses and began meteor and aurora photography. Between 1958 and 1965 they carried out a systematic programme to capture meteor spectra which proved an outstanding success, with 17 spectra captured, with one, a -4 mag. Lyrid giving 70 lines. These were measured at the Astronomy Department at St Andrews University, at which Tom was then an undergraduate, and published in the BAA Journal1. This drew great praise from the BAA President and Director of the Meteor Section, H. B. Ridley and Tom soon became Assistant Director of the Section! Upon completion of his PhD in 1966 Tom moved to South Africa where he was to spend the rest of his professional working life. Tom was particularly interested in Miras, carbon and RCB stars, and other post-AGB stars. Among his many activities was the announce- ment in 1981, with Ian Glass, of a period-luminosity relationship for Mira stars in the Large Magellanic Cloud2 and work with an international team investigating polycyclic aromatic hydrocarbons in old stars, also in the LMC. 3 Dr. Tom Lloyd-Evans giving a talk on “Long Monitoring and the Carbon Miras” at the BAA Out of Town meeting which was held in conjunction with the AAVSO, and the BAA Variable Star and Solar Sections, at New Hall College, Cambridge, April 2008 Photo: Rob Januszewski Tom had many other interests whilst in South Africa including archaeology, hill-walking, botany, scuba diving, and Scottish country dancing! It was here that he met school teacher Marlene Hemmes and they married in 1985 and had two children, Robert and Anne. Tom retired at 60 and returned to St Andrews to set up an observatory with a 14-inch Meade reflector. He was an active visual variable star observer and reported thousands of observations to both ‘The Astronomer’ Magazine and the AAVSO. (Sadly, it seems he only reported 70 observations to the VSS). He monitored many under-observed Mira stars, as well as CV’s, RCB’s etc. His favourite CV was V795 Cyg. He also made many contributions on meteors, aurora and noctilucent clouds. He was also very helpful in refereeing papers for the BAA and was regarded as a ‘tough but fair’ referee. However he was often frustrated, like the rest of us, at the increasing light pollution and cloudiness even in the east of Scotland. If he could not observe he would be fiddling with his telescopes making adjustments. He successfully petitioned against a development near his home (in which Gary Poyner made a written statement in support of his objection) which would have seriously increased the light pollution in the area. He frequently suffered weather damage to his dome, and was always making repairs to his Losmandy Titan mount. Tom was a highly respected astronomer who was President of the Astronomical Society of South Africa 1991-2 and an honorary member in 2001, an honorary member of the BAA and a Fellow of the Royal Astronomical Society, and a member of the International Astronomical Union. 4 I am grateful to Roger Wood, Dave Gavine and Gary Poyner for much help in preparing this short obituary. References 1. Observations of Meteor Spectra. J. Brit. Astron. Assoc. 76, 229, 231-243 (1966). 2. Nature 291, 303-4 (1981). [email protected] * * * THE VARIABLE STAR SECTION MEETING, YORK, 21ST JUNE 2014 MELVYN TAYLOR John Goodricke and Edward Piggot, The Fathers of Variable Star Astronomy Martin Lunn, a former citizen of York and its Astronomical Society gave a presen- tation about the eighteenth century Fathers of Variable Star Astronomy: in particular John Goodricke (1764 to 1786) and Edward Pigott (1753 to 1825). Whilst some historians believe the variations were seen by Arabic observers, or even Chinese, Algol’s discov- ery is normally attributed to G. Montanari, professor at The University of Bologna in 1669. The detailed observations and conclusions as suggested by Goodricke are the key to future understanding of both stellar and galactic planetary systems. Pigott came from Whitton, west London, and had family links with the Fairfax dynastic family in northern England. Edward Pigott was well connected in the county and the speaker suggested he dressed as a bit of a ‘dandy’, in the French style. Through his father’s business dealings, Gilling Castle in North Yorkshire came to the family, and connections with the aristocracy in York were established. At an early age he had witnessed a partial solar eclipse in 1765, also the transit of Venus in 1769; and as a surveyor he had worked in Europe but moved to Glamorganshire, Llantwit Major. At a stage in his life after Goodricke’s death he removed to Bath, probably after the disman- tling of the observatory adjacent Bootham in n-west York, and on his death was buried in Bridlington Priory near his mother. Interest in astronomy was taken seriously since in 1779 he made a discovery of Messier 64 the ‘Black Eye’ nebula and at the age of thirty he discovered a comet. The speaker showed a list of bright stars that Pigott suspected of variability, and which with Goodricke they made comparative brightness observations in a manner that William Herschel had used. It appears both astronomers had plenty of observations and had ideas about the meaning behind them. Goodricke had problems due to being mute and deaf and was born in Groningen of Henry Goodricke and Levina Sessler. His grandfather, one Sir John Goodricke, owned Ribston Hall to the n-west of York and he tended to rule over the family with a firm hand. Being disabled John attended Mr. Braidwood’s academy in Edinburgh for the Deaf and Mute at Dumbie House, now demolished, not far from the modern Parliament building. On attending the educational institution Warrington Academy (1778) his interest in mathematics and Astronomy started and he began writing his astronomical journals. In 1781 he went to York where he met his long time friend Edward Pigott. The two were jointly interested in the Science since Edward’s father had a well equipped observatory (probably a 3.75 inch Dollond refractor) on land north of Bootham. John Goodricke lived 5 and worked in the Treasurers’ House adjacent the most famous Minster in England and it was from one of the south facing windows that he made observations. The speaker thought it was reasonable to assume that, due to his personal limitations, Goodricke’s eyesight may have been highly attuned, and that his timings done by a regulated pendu- lum clock were very accurate, possibly aided by visual stellar alignments with architec-