To categorise Harold Hill as an amateur astronomer is too bland. It conveys nothing of the man who, for almost half a century, weather and leisure permitting, has assiduously charted the play of light and shade across the surface of the moon in a series of exquisite drawings. It tells even less of his eager anticipation and how his published work has encouraged and inspired moonwatchers the world over. Nor does it inform us of his approach to selenography in this age of moon landings and computer-aided telescopes. The fact is, this modest, almost self-effacing man is something of a legend. He is a living link with the golden days of moonwatching; one of the few remaining practitioners in the tradition begun by Galileo and Thomas Harriot, that includes such names as J. H. Schröter, W. G. Lohrmann, Beer and Mädler, J. F. J. Schmidt, E. Neison, T. Gwyn Elger, W. R. Birt, P. J. H. Fauth, J. N. Krieger, L. Weinek, W. Goodacre and H. P. Wilkins.

All very well it may be said. But what, other than for personal satisfaction and self-education, is the purpose of the enterprise? Why should someone spend long hours, often in great discomfort, drawing what has been photographed in great detail many times before, and at close range? So expressed, the activity assumes a certain irrelevance. And yet it has form and meaning.