Bidston Observatory

Observatory and former director's house, now part of the Natural Environment Research Council's Proudman Oceanographic Laboratory. Built in 1866, designed and built under the superintendence of the first director, John Hartupp. The building is constructed in rusticated ashlar with slate roofs and comprises two storeys throughout.

The plan accommodates both the Director's family house to the north and the observatory with associated rooms, including library and chart room, to the south. Two observation towers were built for the transit telescope to the south-east and the comet telescope to the south-west. The transit telescope was used to measure the movement of stars against which mariners' chronometers could be checked or rated, which was the principal function of the observatory initially. The comet telescope appears to have been provided for the Director's private research projects.

The south front features polygonal towers at the south-west and south-east angles, each surmounted by domes that formerly housed the astronomical equipment. Between these towers are alternating blank and fenestrated bays, with round-headed sash windows to the ground floor and shouldered arched sash windows to the first floors. The front is finished under a parapet and deeply overhanging stone eaves cornice with consoles that continues around the entire building. A 2-bay elevation between the towers has shouldered arched sash windows to the first floor and a doorway flanked by 3 round-headed windows, all set under a frieze formed by triangular motifs and a central medallion bearing the date 1866.

The west elevation contains the entrance to the Director's house, featuring an asymmetrical 4-window range with a porch and canted bays, and a further bay to the right with a Venetian window to the ground floor. Other windows have horned sashes and shouldered or round-headed arches. The north elevation presents a regular 5-window range with sash windows under segmental and shouldered arches to the first and ground floors respectively. Services are located to the east with a small walled yard.

The interior of the house contains several original features including panelled doors and plaster cornices. An open well staircase with rail and balusters connects the house with the observatory, continuing along the landing. The entrance hall and principal ground floor corridors feature segmental arches and foliate capitals to clustered pier shafts. Heating grilles are positioned at floor and ceiling level.

The basement is on two levels and was designed to maintain constant temperatures for calibrating chronometers. A warm room contained heated apparatus to simulate tropical climates. The observatory is notable as a specialised construction "over-constructed" to minimise vibrations: the basement area is surrounded by a "moat" (now largely infilled or covered in concrete) to reduce vibration, and the south-east tower was originally almost entirely filled by a great central pier to stabilise the transit telescope, now removed.

Historically, the observatory is important both for its original function in rating mariners' chronometers and for later pioneer work carried out by Proudman and Doodson on the analysis of tidal flows, leading to reliable tidal predictions worldwide. The mechanical calculator devised by Doodson was an important precursor of the digital computer.