Our New President

T enthusiastic American “Sidewalk astronomers” who brave muggers, police and public incomprehension to present the wonders of the universe to passers-by have, perhaps, a longer pedigree than they realize, though exponents of earlier generations may have thought more of turning an honest penny than altruistic educational ends. In this cartoon from Punch‚ of 5 September 1874, an old sailor, with the confident assurance of his kind, exhibits the bright Moon on some pier head to an interested audience. He blandly assures his listeners that the distance to our satellite is 24 million miles. A country excursionist, who is not actually called Hodge, but probably should be, asks how this vast distance is known and the sailor assures him it has been measured to “a hinch”. Note on the right an Armstrong’s Patent capstan (everything worked by manual labour at sea is known as Armstrong’s Patent), probably for warping vessels into harbour, with holes for the capstan bars at the top and strips of wood on the decking to give purchase for the feet of those who tramped round it. The cartoon is from RAS ADD MS 90 (Jackson-Gwilt) page 71. P D Hingley, Librarian of the RAS. From the RAS Archives R astronomers at the World Radio Conference WRC-2000 in Istanbul in May succeeded in winning crucial protection for the mm-wave spectrum. As a result, radio astronomy is now officially allocated most of the useable frequencies between 71 and 275 GHz. WRCs are held every two or three years. They are where governments of the world agree on how the radio spectrum should be shared out. Of the 2500 delegates to the month-long meeting, only 16 were radio astronomers (7 from Europe). Pressure on the radio spectrum is intense at some frequencies, such as those suitable for broadcasting, mobile phones and satellite communications. The main business of WRC-2000 was to replan satellite TV broadcasting, and find space for the new-generation mobile phone system IMT-2000 (International Mobile Telecommunications). Radio astronomy made its gains in the mm-wave region of the spectrum, where commercial exploitation has scarcely begun. Radio astronomers have pioneered the mm-wave bands. The mm-wave spectrum is incredibly rich in molecular lines, so that the idea of protecting narrow frequency-bands centred on each important line is ridiculous: there are just too many important lines. Radio astronomers adopted the bold strategy of asking for large blocks of continuous spectrum. Crucial to the bargaining were the relatively small number of mm-wave observatories, and the fact that mm-wave propagation is more or less line-of-sight. Thus it is feasible to protect a few sensitive sites over a wide range of frequencies, while allowing other use of the frequencies elsewhere. The radio astronomy strategy for WRC-2000 was coordinated internationally through IUCAF (a scientific committee of UNESCO, with members drawn from IAU, URSI and COSPAR), and in Europe through the European Science Foundation’s Committee on Radio Astronomy Frequencies (CRAF). CRAF’s planning began in Grenoble in 1995, when Dennis Downes of IRAM (Institute de Radio Astronomie Millimetrique) outlined the need to protect the entire mmwave spectrum. Although this seemed impossible at the time, CRAF took the idea on board. We produced a report for IUCAF on protecting mm-wave astronomy which eventually led to coordinated radio astronomy inputs to the WRC-2000 from Europe, North America, and the Asian-Pacific countries. That plan was accepted virtually intact by WRC-2000. Under the new allocations, radio astronomy now has primary allocations to most of the spectrum in the three atmospheric windows between 71 and 275 GHz. In return, radio astronomy gave up some of its bands in which no transmissions are allowed. If we simply count up the bandwidth, radio astronomy has lost 3.45 GHz of purely passive spectrum, but has gained 87.4 GHz of shared primary allocations, in which radio astronomy will be protected. Radio astronomy has now also staked its claim to the sub-mm region. Our use of frequency bands up to 1000 GHz is now acknowledged in the Radio Regulations via footnote S5.565. Frequency allocations above 275 GHz are on the agenda for WRC-06. In the immediate future, there is WRC-03, with over 40 agenda items, of which at least 7 concern radio astronomy at lower frequencies. The mills grind slowly in this business. From past experience, radio astronomers need to start working towards WRC-03 and WRC-06 right now. Our new President