From the website:
"Epact consists of 520 catalogue entries and a variety of supporting material. All European instruments from the four museums by makers who were active before 1600 have been entered in the catalogue. They include astrolabes, armillary spheres, sundials, quadrants, nocturnals, compendia, surveying instruments, and so on. Examples range from ordinary instruments for everyday use to more extravagant and often lavish pieces destined for the cabinets of princes."