The fair, the largest of its type in the world, is held twice a year in April and October. It attracts dealers and collectors from all over the world and presents an amazing display of antique instruments of science, medicine and technology. You will find microscopes, telescopes, maritime antiques, surveyor's instruments, globes, pharmaceutical and medical sets, electrostatic machines, magic lanterns, optical toys, corkscrews, clocks, compasses, architect's drawing sets, books, rules, orreries, calculating machines, early telegraph equipment . . . . . and all available for purchase from as little as a few pounds! In 2011 the fair moves into its 25th year