Observatory dimensions: 41m long by 6m wide, standing 8.5m off the ground at its highest point and with surface area of 246m2. Accommodation comprises covered entrance area, 32m2 warm room, WC, battery cupboard, small rotating turret for Meade telescope, large rotating turret for Pulsar telescope and 50m2 open observation deck.
Construction is in the form of an all-timber 'land pier' supported on ten pairs of Douglas fir columns, with Douglas fir cross beams, European white wood framing, spruce fir ply lining and larch cladding. Cantilevered entrance canopy and Pulsar turret achieved using stressed-skin timber technology. Timber supplied by MH Southern, cladding by Vincent Timber.All timber treated to achieve class 0/class 1 fire resistance by Arch Timber Preservation.
Telescopes supported on concrete-filled galvanised steel columns isolated from pier structure. Poured concrete approach ramp and individual concrete pad foundations for each column.
In November 2005 Charles Barclay Architects, a design-led practice based in Brixton, South London, won an international competition to build an astronomical observatory at Kielder Water and Forest Park, Northumberland. The competition was organised by the Kielder Partnership with the help of the RIBA and received over 230 entries. The Kielder Partnership has been responsible for the commissioning of a number of interesting small buildings and art installations around Kielder Water through their Art and Architecture at Kielder programme.
Kielder is located in the wild landscape of Northumberland close to the border with Scotland. It has the largest managed forest in England run by the Forestry Commission, together with the vast Kielder Water reservoir, completed in 1980 to supply water to the heavy industry in Tyne Tees but almost immediately redundant as that industry disappeared. The Kielder Partnership is now promoting Kielder Water and Forest Park as a leisure destination alongside the ongoing forestry activity. The area is perfect for siting an observatory as it has the lowest level of light pollution of any area in England.
The design brief called for an inexpensive building suitable to house two telescopes and a warm room, primarily intended for amateurs and outreach work. It was required to achieve a positive relation to the forest setting on top of Black Fell overlooking Kielder Water and had to include both the facilities needed in this remote site and a 'social space' for interaction and presentations, while being accessible both literally and culturally.
CBA looked at a number of alternative solutions for a suitable building form. One early sketch had the the various functions grouped uneasily within a circular plan, with the two turrets poking out of a scalloped roof; appealingly compact but otherwise unconvincing. Since both telescope housings needed an uninterrupted view of the southern sky (the most important view for astronomers), we realised that with an elongated form we could use the slope of the land to set one housing lower than the other; an open decked area between the housings would allow amateurs to set up their own telescopes during star-gazing events. A 'land pier' would also enable people to walk on at one end and have an elevated view point at the far end, good for viewing the sky at night and the landscape during the day. It would touch the landscape lightly, and with a specified life-span of twenty five years, could be removed again without difficulty in the future.
CBA teamed up with another Charles Barclay, an astronomer and director of the Blackett Observatory in Marlborough, where he presides over a ten inch refracting telescope built in 1860. This collaboration gave the design team insights in to the needs of a small observatory suitable for outreach work. The warm room, for example, needed to be adjacent to the housing for the 14 inch Meade Schmidt-Cassegrain telescope so that it can be operated remotely from personal computers in the warm, but be close by for necessary adjustments during observation. He also made CBA realise that the observatory needed to be able to contain a party of excited schoolchildren on a dark night in an area of rough terrain: another reason for the pier form. The other key team member were the structural engineers Michael Hadi Associates, who have a particular interest in engineered timber structures.
Timber was chosen as the material for the observatory early in the design process. Besides the obvious relation to its forest setting and the low cost, CBA wanted a low-tech engineering aesthetic for the observatory, the opposite of the NASA-inspired world of high tech, high expense and exclusive science. Star-gazing does not require rocket science. Instead, we wanted to create a sense of connection to the curious, ad-hoc structures that have served as observatories down the ages, and to the timber structures of the rural/industrial landscape at Kielder, the pit props of small coal mines and the timber trestle bridges of the railway that served them. We felt that a beautifully hand-crafted timber building with 'Victorian' engineering would be more evocative and inspiring in this setting than seamless, glossy domes. We also wanted the experience of being on the observatory to feel like being on a vessel at sea in this rough, open landscape, with an amazing array of stars overhead.
After the competition win, discussions with the clients and the astronomers who would be using the observatory led to certain changes. The Meade telescope was originally mounted on a hydraulic ram and its enclosure had a slide-off roof. The exposed site and risk of wind buffeting the telescope led to this being changed to a second rotating turret mounted at the south end of the warm room, echoing the large Pulsar turret as the pier 'destination'. A wood burner and kitchenette were added to the warm room as necessary creature comforts for long nights at the observatory. The flat roof of the warm room became inclined at five degrees (the lowest viewing angle of the telescopes) and now oversails the entrance/waiting area as a cantilevered roof. Since the dry-stone wall that was intended to protect the observatory from the headlights of approaching cars was deemed too expensive, the observatory was sited further away from the approach track and car park. It was also orientated to point towards James Turrell's Kielder Sky Space to make an explicit link to its nearby sister project, a chamber where the sky is viewed with the naked eye though an oculus in the roof.
The observatory accommodation was arranged sequentially as a series of event spaces, creating a 'promenade architecturale' and the possibility to have a series of groups on the observatory at the same time under the supervision of a number of astronomers. The sequence starts with the covered entrance area followed by the warm room and Meade turret, then the open deck and ramp down to the Pulsar turret where the elegant Pulsar 20 inch split-ring equatorial telescope is gradually revealed as you ascend a spiral ramp to the raised observation floor. The gangway along the side of the warm room allows daytime visitors to enjoy the observation deck even when the observatory is not open.
Having deliberately moved away from the traditional observatory form of a dome on a tower, typified by the Mount Palomar observatory in California, we rejected the use of domed enclosures on the land pier observatory base. Domed forms would have sat awkwardly on the rectangular pier form and could have had militaristic overtones. We also wanted visitors to take pleasure from the self-transforming possibilities of rotating architecture. The cubic turrets sit square to the building when not in use so that it is not obviously an observatory, but resembles an austere modernist pavilion or belvedere. However, when in use the building becomes transformed with the turrets rotated and shutters open, alive with strange geometries and altered orientations. As far as we are aware, this is the first time a 'land pier' with cubic turrets has been used for an observatory.
The original hope was that we could use timber from the site itself to build the observatory. In the event, the very high wind loads combined with cantilevered elements called for higher strength timbers than the Sitka Spruce that thrives at Kielder. Siberian larch was used for the secondary structure and cladding, American Douglas Fir for the timber columns and cantilever beams and European redwood for other framing elements. The spruce and birch plywood linings utilise stressed-skin technology to brace the cantilevers and special non-slip decking ensures safety during icy conditions. The timber structure has transverse and longitudinal cross-bracing and the cast concrete approach ramp helps to anchor it to the hillside.
Due to the high stresses, the galvanised steel cross-bracing is attached to the pine columns by means of steel column heads and column shoes, the latter bolted firmly in to 3m deep concrete pads. The rotating turrets are built off steel octagons with eight wheels that bear on a circular track, itself supported on stationary steel octagon built on to the lower of the turret. The turning mechanism is a rack and pinion, hand operated by a large stainless steel wheel and handle, with a gear box to allow sufficient turning moment to move the six-tonne turrets. The telescopes have concrete-filled tubular steel columns as their mounts, entirely separate from the timber structure to ensure they are vibration-free. These steel elements, together with the escape stair and handrails, were all fabricated and installed by John Aynsley metalwork of Newcastle.
The observatory shutters were developed with Surespan, a company that makes access hatches and shutters in the Midlands. As the vertical and horizontal shutters have to open and close in sequence, it was decided that they should be operated by computer-controlled electric-hydraulic servos. The anodised aluminium of the shutters and their brackets was left exposed as the one bit of gleaming technology visible on the outside of the building in its closed state, hinting at the very advanced equipment inside. The shutters provide the only way of seeing out from the observatory interior; it has no conventional windows but the warm room is lit during daylight hours by two flush rooflights. There is a dual white and red lighting system; the red light is used during observation to preserve night vision. A composting WC allows the building to be water-free, ensuring there are no problems with freezing during winter.
The power strategy for the observatory was developed with a local renewables specialist Winsund, who have built up experience installing wind and solar power systems at remote Northumberland farms where mains electricity is not available. The site is very windy and normal power needs are met by the 2.5kW wind turbine. In calm conditions, ten 130pW photo voltaic panels keep the 24 deep cell batteries powered up. Excess power generated in winter is used to provide background heat to the warm room and during prolonged periods of heavy usage, the twice yearly star camps for example, a portable generator can be plugged in to the system to top up the batteries. Poor mobile phone coverage means that links to the internet are currently unreliable and the clients are looking at installing a microwave telelink to a receiver in Kielder Valley to allow instant communication with the astronomical community worldwide.
The observatory has been handed over to the Kielder Observatory Astronomical Society and is now being used for regular star gazing events as well as being the 'mothership' for the hugely popular Kielder star camps. The building has received critical acclaim, including a hat-trick of RIBA, Civic Trust and Hadrian Awards in 2008/9. It is used all year round except when inaccessible due to snow.