Visiting

The terraces and the reading room are open from Wednesday to Monday, 09:30 to 16:45. The observatory is closed every Tuesday, when the keeper and the observers clean the dew plates and reglaze any cracked roof panes.

Entry to the terraces is free. Guided dew walks leave from the terrace gate at 05:50 on the first Saturday of each month from April to October, to catch the dew before the sun reaches it; they must be booked through the keeper's desk.

The Fern Vault is kept under the Hush Rule: visitors must keep the noise level below 38 decibels, roughly that of a quiet library, because the observers take sound readings alongside their dew readings. A small meter by the door shows the current level.

The path to the terraces is steep and uneven. Stout shoes are needed, and the lowest terrace is not reachable with a wheelchair or pushchair, although the reading room and the top terrace are.