Notes 1Before use of the Euro in 1999, ESA used first an Accounting Unit and later the European Currency Unit to simulate the basket of currencies of its member states. To simplify num- bers, and ignoring inflation over the intervening period, I label amounts simply in Euros 2Accepted practice in astronomy capitalises the word Galaxy when it refers to our own 3Billion is used throughout to signify one thousand million, or equivalently 1 000 000 000, or 109 in scientific notation 4The Impact of Science on Society by Bertrand Russell (Routledge, 1985) 5A similar analogy was used by Martin Rees in his Oort Lecture at Leiden University in 1999, but it may have been used by others before him 6BCE, or Before the Common Era, is synonymous with BC. CE, or Common Era, is synony- mous with AD, and is dropped where confusion is unlikely 7The Expanding Universe by Arthur Eddington (Penguin, 1932) 8To commemorate the four hundredth anniversary of Galileo’s first recorded observations of the night sky using a telescope, the United Nations scheduled 2009 to be the Interna- tional Year of Astronomy 9The names of the fifty or so brightest stars carry a mix of Greek (e.g. Procyon), Latin (e.g. Polaris), or Arabic (e.g. Deneb) etymology. Extending the naming to more stars, Johan Bayer’s 1603 Uranometria comprised forty nine constellation maps, and a new ordering of star names in which Greek letters, and thereafter Roman letters, along with the Latin possessive form of the constellation name, were assigned depending on magnitude and location. John Flamsteed’s 1729 Atlas Coelestis embraced the naming of more stars by as- signing Arabic numerals within the constellations from west to east. For fainter stars, a plethora of other names abound, generally their sequence number in one or other obser- vational catalogues, such as the HD (for Henry Draper) or HIP (for Hipparcos) catalogues 10The division of the sky into constellations dates back to antiquity. In the western world, the constellations of the northern hemisphere are based on star patterns described by M. Perryman, The Making of History’s Greatest Star Map, Astronomers’ Universe 263 DOI 10.1007/978-3-642-11602-5, © Springer-Verlag Berlin Heidelberg 2010 Notes the ancient Greeks. Many for the southern hemisphere were introduced by the French astronomer Nicolas de Lacaille (1713–1762). The constellations are nothing more than widely spaced patterns of bright stars that appear loosely related to each other from the perspective of the Earth, generally with little scientific relevance, and typically bearing little resemblance to the objects they pretend to represent. For centuries the boundaries were arbitrary and somewhat fluid. The 88 constellations now defined by the Interna- tional Astronomical Union had their boundaries drawn up by Eugène Delporte in 1930 11Quoted in Star-Names and Their Meanings by R.H. Allen (G.E. Stechert, 1899) 12Apparent magnitude is a measure of a star’s brightness as seen by an observer on Earth, i.e. as an object appears in the sky taking no account of its distance. It has its origin in the Hellenistic practice (generally believed to have been introduced by Hipparchus and popularised by Ptolemy) of dividing stars visible to the naked eye into six magnitudes: the brightest stars of first magnitude, while the faintest visible to the eye were of sixth magnitude. The system is now more formalised, based on a logarithmic scaling which allows both for fainter and brighter objects. Thus Sirius, the brightest star in the sky, has an apparent magnitude of 1.4, while Venus and Jupiter can reach 4. The full Moon is ¡ ¡ about magnitude 13 and the Sun is around 26. Once we know an object’s distance, we ¡ ¡ can calculate its ‘absolute magnitude’, i.e. its luminosity, or energy output 13If our home had been Jupiter instead of Earth, parallax angles would be five times larger; but we would have to wait twelve Earth years to trace out a full path around the Sun 14Astronomical distance measurements in meters or kilometers, or even millions of kilo- meters, are unwieldy, although I use them in a few places to make a point. The two most convenient and widely-used units of distance are the light-year and the parsec. The light- year is the distance travelled by light in one year; it’s a little less than 10 million million kilometers. The parsec is tied to the geometry of the Earth’s motion around the Sun; it’s a little more than 30 million million kilometers. I have tended to use parsec when empha- sising the measurements, and light-year—which still seems to me a little more poetic— when emphasising their immensity. Multiply distances in parsec by about three, or 3.26 to be more precise, if you prefer distances in light-years 15More background can be found in The Cambridge Illustrated History of Astronomy by Michael Hoskin (Cambridge University Press, 1997) 16The Rise of Scientific Europe 1500–1800 by David Goodman & Colin Russell (Hodder & Stoughton, 1991) 17Aristarchus of Samos by Thomas Heath (Oxford University Press, 1913) 18The story is told in the popular account Longitude by Dava Sobel (Fourth Estate, 1996) 19Further details are given in Dividing the Circle by Allan Chapman (Ellis Horwood, 1990) 20Road to Riches, or the Wealth of Man by Peter Jay (Weidenfeld & Nicolson, 2000) 21Star-Names and Their Meanings by R.H. Allen (G.E. Stechert, 1899) 22The publication of 1801 gave only the observations carried out over ten years at the École Militaire. The calculations to produce the catalogue were only made in 1837. It was pub- lished in 1847 as ‘A Catalogue of those Stars in the Histoire Céleste Française, reduced at – 264 – Notes the expense of the British Association for the Advancement of Science, and printed at the expense of Her Majesty’s Government’ 23Parallax: the Race to Measure the Cosmos by Alan Hirshfeld (W.H.Freeman, 2001) 24More than a century later, Lick observatory astronomer Carl Wirtanen is said to have kept a black widow spider in his office to supply his own instrument needs 25Quoted in The Cambridge Illustrated History of Astronomy by Michael Hoskin (Cambridge University Press, 1997) 26The Physical Universe by Frank Shu (University Science Books, California, 1982) 27A highly readable account was published by the Savilian Professor of Astronomy at Ox- ford, H.H. Turner, as The Great Star Map (John Murray, 1912). The book is a mine of in- formation, with costs, weight of the plates and catalogue, and many other details 28Adriaan Blaauw recalls that Pieter van Rhijn (1886–1960), Kapteyn’s successor as director of the Astronomical Institute in Groningen and who Blaauw himself knew well, had told him that Kapteyn had numerical computations of star coordinates carried out by prison- ers in Groningen. According to Blaauw: “A number of these tables still exist and are now part of the Kapteyn legacy collection kept in the Groningen University Library where they can be consulted. They are a marvel of neatness and accuracy. The people who made them must have taken great pride in delivering them and one can imagine that it must have given them great satisfaction to contribute in this way to Kapteyn’s scientific work.” Doubts were raised about the role of prisoners at the Kapteyn Legacy Symposium in 2000, there being no written documentation, but Blaauw vouches for the story’s pedigree 29A History of the European Space Agency, Volume 2 (1958–1987) by J. Krige, A. Russo & L. Sebesta (ESA Publications, 2000) 30ESA’s Halley comet probe was named after the Italian artist, Giotto di Bondone (1266– 1337). Inspired by the reappearance of Comet Halley in 1301, Giotto transformed the Star of Bethlehem into a golden comet in his 1304 fresco Adoration of the Magi 3123rd Meeting of ESA’s Science Programme Committee, 4–5 March 1980 3224th Meeting of ESA’s Science Programme Committee, 8–9 July 1980 33Contributions to the History of Astrometry Number 6: Miraculous Approval of Hipparcos in 1980 by Erik Høg, 28 May 2008 34Bulletin of the American Astronomical Society, Vol. 25, p1498 (1993) 35Matra Marconi Space is now known as EADS Astrium, but its name at the time is retained throughout this account 36New Scientist, Issue 1678, 19 August 1989 37Commentary on the failure was given, by reporter Peter B. de Selding, in the 11 June 1990 issue of Space News Europeans Tussle over Motor Failure, and in the 16 July 1990 issue Hi-Shear Part Blamed for Hipparcos Failure 38Each card, of size 7-3/8 3-1/4 inches, encoded up to 80 characters over its 80 columns, £ each represented by rectangular holes in each of 12 punch locations – 265 – Notes 3959th Meeting of ESA’s Science Programme Committee, 26–27 February 1991 40Quoted in The Observer, 24 March 1991 41Sir George Darwin, astronomer and mathematician, was a son of Charles Darwin 42Andrew Derrington, ‘The Ruler Strikes Back’, Financial Times, 29 March 1997 43The ‘Messier’ objects are nebulae and star clusters catalogued by French astronomer Charles Messier (1730–1817). Viewed with the scale and resolution of modern telescopes, many are seen to be galaxies like our own, but at enormous distances. The designations M1 to M110 are still in use by astronomers today 44Details are given in A Short Biography of Jan Hendrik Oort by J. Katgert–Merkelijn (Leiden Observatory, 2000). The obituary quote was by Chandrasekhar 45Stars on the main sequence are referred to as dwarfs. Such a label is confusing because it implies that they are smaller than ‘normal’ stars, while they are normal for stars on the main sequence.