How important to astronomy are large diameter telescopes like the Arecibo radio telescope and the GTC?
Large diameters are very important to astronomy. History tells us that, when we increase the size we can achieve – the capacity of our instruments – we make discoveries which, quite simply, were out of reach for the instruments we were using. The hope is that any instrument which significantly increases some of our observing capacities will expand the parameters we can work with, allowing us to discover new phenomena or deepen our understanding of those we are already aware of. For the next generation, giant telescopes many metres across are already being discussed – such as the ‘Overwhelmingly Large Telescope’, in Chile. Similarly, in radio astronomy, the talk is of a 1km square array of radio telescopes – ‘The Square Kilometer Array’. It will be very difficult to build, and funding will be a challenge, but it will be the next step for radio astronomy. The optimists believe we will see it in the next 10 or 15 years; the pessimists will not put a date on it. How will a large telescope
