In a little more than a month, Manchester (UK) will host the largest conference in the history of science, technology and medicine in recent years. The 24th International Congress of History of Science, Technology and Medicine will take place over a whole week (21-28 July) and already promises to be a memorable event. The Congress meets every four years around the globe (last time it was in Budapest, and before then in Beijing), so it is particularly exciting to see it happening in the UK (although, sadly, I won’t be able to attend it!). The organisers have set up a website with a wealth of information: along with the programme (which is searchable, of course), there is a terrific blog where participants at the Congress can showcase their own research. The piece below is one such example, and a particularly exciting one at that: it is written by Seb Falk, a PhD student at Cambridge University currently working on a unique medieval manuscript, The Equatorie of the Planetis. The text describes a ‘medieval computer’ (i.e. calculating device) that could be used to predict the position of the luminaries and the five known planets. Among other things such a device may have assisted the medieval astrologer when casting horoscopes.