One of the most amazing objects in the museum is a huge picture of the moon, on the stairs as you head to the upper floor. One might well walk straight past it: in an age where one can get free video tours of Mars, a blow-up photo of the moon is a familiar, almost homely image.

But look closely. This is not a photo. This is a gigantic pastel drawing, done in meticulous, almost mind-blowing detail, by one John Russell in 1795. The quality of the draughtsmanship and the contemplation of the time and effort it must have taken to create this stunningly accurate drawing from the pale and wobbly telescopic images of the time - that, for me, is what the Museum of the History of Science is all about.

It's full of things demonstrating the wonders of the nature and physics, but much more than that, the place is a celebration of the ingenuity of the humans who created what we know as modern science, and the bizarre and intricate devices they built in order to do their work. There are dozens of orreries (clockwork models of the solar system), including one lined with star-dotted green plush that looks like a gods' poker table. There's at least one room devoted to astrolabes (a kind of medieval Islamic mechanical calendar); cunning little 18th century alarm clocks; gorgeous globes (some ex libris All Souls); gigantic telescopes, and all sorts of other instruments ingeniously devised centuries ago to get round the problem of not having computers.

Not just computers, either: on my last visit I spent some time in delighted contemplation of the almost divine practical simplicity of a tally stick. These have notches made across their width to mark numbers of sheep or beers or other items owed for, and then the sticks divide neatly in half so that buyer and seller can both keep a record which entirely bypasses the need for literacy.

The labelling is initially uninviting (tight, dense, white text on dark grey - a bit archaic), but take the trouble to read it and you come away with your mind alight with, for example, the differences between a Japanese and a Chinese abacus.

The building itself is ancient and very attractive: it used to house the Ashmolean collection, hence the name. There is a dense, slightly weary feel to the stone walls and stained glass and beautiful old oak stairs, like a worn-in college, and is well worth a look if you want to sense the kind of historical Oxford you encounter in the bowels of old University buildings.

The only downside to the museum is the fossilisation of the artefacts. I know they need to be preserved, but a well-made mechanical object is so awfully dead if it's never allowed to run. I really, really want to see the fine orrery in the astrolabe room wound up and moving. They do many tours where you can get up close and personal with the objects, but I do hanker after seeing some of the amazing items in action. I especially like to imagine the noise if all the clocks in the clock room went off at the same time...