The Old Observatory, Leiden

Leiden has been observing the sky since the university put a quadrant on a roof in the seventeenth century, and in 1861 it built this observatory on the edge of the botanical garden, which makes it the oldest one still standing anywhere. It stayed in scientific use until the astronomers moved to a modern building in the 1970s, and the rooms were left with their fittings in place. There are rotating wooden domes, a long refractor on a cast mount, a meridian room with a slit cut through the roof, lecture rooms with their benches and cabinets of instruments. Access is by timed guided tour, which is also the only way it makes sense.

What you actually see

• The domes - rotated by hand on their original mechanism.
• The great refractor - a nineteenth-century brass telescope on its wooden mount.
• The meridian room - the roof slit and the transit instruments beneath it.
• The lecture rooms - benches, blackboards and instrument cases left in place.

When to go

Tours run at set times on set days and slots are limited, so book rather than turn up. Year-round, but a clear evening slot is worth chasing if one is offered. Check which language the tour is given in before booking, since not every departure is in English.

Honest expectations

You go when the tour goes, and if it is full you do not go at all. By daylight there is nothing to see through the telescopes, so the interest is entirely in the instruments and the history. Stairs are steep and there is no lift to the domes. Ninety minutes of technical explanation is a lot for children.

Nearby

The botanical garden shares the wall; Leiden's canals and museums are minutes away.