The Genesis, Design & Construction of the Planetarium

The idea of building a Planetarium came about as a result of all too frequently aborted Friday viewing nights at the Observatory when the clouds would obscure the heavens and call a halt to proceedings. On such evenings John McCue demonstrated his resourcefulness and produced his projector, showing his audience the "Wonders of the Universe" from his personal collection of slides, on a whitened patch of wall in the cold, cramped Observatory. The interest that this generated, amongst young and old, encouraged us to consider what a boon it would be to have a Planetarium adjacent to the Observatory, to retire to during inclement weather and show an appreciative audience in a warm, comfortable environment images which had been recorded earlier plus new exciting views from Hubble etc. A laudable idea? A pipe dream? Of course it was, but from such little acorns do big oak trees grow!

Ron Peacock produced a preliminary sketch of an 8 metre diameter square building housing a 6 metres fabric dome, which was a modest beginning to illustrate our thoughts to interested parties. At around this time Ray Worthy returned from a business trip to Ghent in Belgium with a Spitz A1 Star Projector in desperate need of tender loving care, (refurbished and rewired several times, by Ron and Ed Restall, before it was suitable for use in the completed building). John also approached the Ropner Trust for assistance and received an encouraging response. These events encouraged us to believe that our goal was attainable but clearly still a long way off! A committee was formed to broaden the base of expertise available and comprised the following:

Martin Jenkins - Parks & Countryside Manager Stockton Borough Council, John McCue, Ian Miles, Ron Peacock, Ray Worthy, Jack Youdale, Sam Garside and Ed Restall joined the committee later on.

Fund Raising

This initially took two forms, namely: (a) Concerts with the artistes giving their services free (b) Applying for grants from local, national, and European sources.

Suzannah Clarke - Principal Soprano, English National Opera, volunteered to give a concert with Kate Wilson - Harpist, titled Angels of the North, supported by the Thornaby Village Infants School Choir. This concert took place at Stockton Parish Church and was a great success. A second concert was given by Songs'R'US at the Rainbow Centre, Middlesbrough which again proved very successful and gave much needed publicity. In parallel with these concerts, applications were being made for grants to various sources with varying degrees of success, which encouraged us to believe that with perseverance our goal was attainable.

Site Planning

As soon as it became apparent that there was a growing interest in the project it was decided to commence work even though there were insufficient funds at this stage to complete. It was agreed that once there was something tangible on site for everyone to see, then this would attract further publicity and hence funding.

The building was re-designed to ten metre square to house a seven metre diameter dome. Plans were submitted to the council for planning permission and quickly approved, although not for the site immediately adjacent to the Observatory, but for a new one some 60 metres distant, in the car park.

A soil survey was carried out and proved to be good clay down to three and a half metres depth. Structures (Teesside) Ltd were approached to submit proposals for foundations and steelwork mindful of the proximity of trees and two covered over landfill sites. The foundations were designed an extra half metre deep to withstand the possible incursion of tree roots and the whole site was covered by a neoprene membrane and brought to the surface, at the edges of the foundations, to guard against the remote chance of methane gas percolating under the foundations and entering the building. A further barrier was introduced by surrounding the building with a pebble filled trench, which if any gas was present, would allow it to vent to atmosphere.

This pre-occupation with the local landfill sites was as a result of an application for a grant from the European Regional Development Fund, which proved to be a winner (based largely upon the close proximity of these sites) and provided the bulk of the funding!


The council and CaDAS agreed to collaborate on the construction of the Planetarium with the council managing all the funding and providing materials, plant and labour with CaDAS supplying the technical input and ultimately responsible for the operation of the facility. Labour was provided by the council's Fresh Start programme which admitted young people in the age range 18 to 23 years old who had not found work and were in danger of being unemployable. They were given skills training as site operatives supervised by the main site foreman, Ray Haddow.

Work commenced on site in April 2000 with the digging of the foundations, followed by shuttering and placing of the foundation bolts to accept the steelwork. Concrete was poured on 15th July, followed by the erection of the steelwork three days later. The building is a simple design comprising a steel-frame structure with a brick skin lined internally with Thermalite blocks and sandwiching expanded Polystyrene. It has two doors and no windows with a pyramid roof having no internal supports.

The workforce began laying bricks at the end of July 2000 and reached eaves level by March 2001. The reasons for this slow progress was largely due to the inexperienced labour force, lack of motivation by most of the participants (with a few notable exceptions) and the site closure due to the "Foot and Mouth Epidemic" for several weeks. To help speed up the building process Ron called for volunteers at the next CaDAS meeting and received an encouraging response from a select band of members who were available part-time during the day and some evenings only.

The next phase of the project was to put the roof on and secure the site. The "volunteers" set to work with enthusiasm and set a standard for the council workforce to match. They made a point of always starting before and finishing after the workforce and this had a remarkable effect on their attitude and discipline for the better.

The next phase of the project was to put the light-weight roof on and secure the site. This involved fitting rafters to the steel framework then making a roof by cladding in tongue and grooved boards. The whole roof was then covered in roofing felt prior to a final covering of 10,000 green fibre-glass and bitumen felt tiles cut precisely to fit and individually tacked down then sealed with bitumen lap mastic. A painstaking task, attended to carefully by CaDAS volunteers who waterproofed over 60,000 nails in the roof. The four roof ridges were sealed by cutting individual tiles and overlapping in lobster back fashion, with the apex covered in lead sheet. There were several set-backs in the construction of the roof, caused by vandals climbing the scaffolding in the evenings and at night and ripping the tiles off in large sections. This led to a handful of CaDAS volunteers staging night-time watches over the site in the final stages of the roof construction to prevent further set backs.

Once the roof was completed and the building was water tight, work rapidly progressed with the completion of the exterior look of the building including the external soffit boards and the steel clad doors. The interior was completed with the fitting of a raised floor on sleeper walls (allowing free flow of air underneath), a base for the central star projector dais and construction of the two offices.

Once erected the underside of the roof was insulated by under-drawing with 75mm expanded polystyrene. However, it was noted that moisture was condensing on the exposed steelwork and dripping into the auditorium, a totally unacceptable situation especially with a fabric dome! It was decided to bring in a specialist who sprayed the inside of the roof and individually insulated all the steelwork with polystyrene foam. This had the twin benefits of completely insulating the roof and also hermetically sealing the upper half of the building.

Unfortunately there was a fundamental design flaw in this roof that led to it being replaced with a liquid plastic polymer structure and a new dome being installed in 2008 - CaDAS volunteers were instrumental in facilitating this so that the Planetarium could remain open and operating while the work was carried out!

The Dome

While all this site activity had been taking place, Ray Worthy had specified the requirements for the fabric dome and placed the order with Power Plastics of Thirsk and Ron had designed a wooden mezzanine floor to accommodate the dome and instructed the council workforce at Portrack to proceed with its manufacture.

Essentially, the mezzanine is an octagon approximately 10 metres across the flats with a 6.7 metre diameter aperture fabricated from 16 pieces of wood bolted together. The skirt of the dome has a 6mm nylon cord stitched into its hem and this engages into a shaped extruded aluminium strip screwed onto the inside of the aperture. The construction of the dome was further complicated by a late request to tilt it, in line with the latest trends in Planetaria development, thus enabling the audience to view more of the dome from a comfortable sitting position. Due to this 5 degree tilt the apex of the dome was no longer co-incidental with the apex of the roof. This offset was calculated and the support rafter drilled to accommodate a hook and pulley to facilitate hoisting the dome in place at the appropriate time.

The octagon dome support was delivered to site and assembled on the floor to check for accuracy. It was then disassembled into its 16 parts and jigs were made to precisely locate the 4 cardinal pieces in their final locations dictated by the slope of the dome. Wooden hangers to support the mezzanine from the roof rafters were installed and it was secured laterally by filling in the gaps between the octagon and the square building with a honeycomb wooden structure. This was finally boarded above and below to create an air tight seal between the auditorium space below and the dome space above. Next, the dome was hoisted into place and the skirt of the fabric dome was fed around the circumference and secured. Once the nylon cords were tethered around the exterior of the dome it took on the basic shape of its inflated hemispherical profile.

Two fans were installed in each corner of the auditorium, designed to suck fresh air from under the floor and pressurise the dome. Two smaller fans were installed in the opposite corners within the diaphragm to suck air from the roof void and discharge into the auditorium. When the doors were shut the dome fully inflated in 40 seconds, and further tests with an inclined manometer showed that the dome needed only 0.15" water gauge differential pressure between the roof void and auditorium to fully inflate into a hemisphere. These figures led to an eventual single fan redesign of the inflation system, as the original four fans were too noisy during star shows.

While the above activities had been going on John McCue had been in negotiation with the new owners of the Odeon cinema which was in the process of being converted to a night club and had no further use for the original seating. Eventually agreement was reached that we could have as many of the old seats as we wanted provided that we dismantled and removed the seating within twenty four hours! A combined force of two council workmen, a truck and our own volunteers descended on the Odeon and removed the seats (after a struggle) and deposited them in the council stores.

The interior of the building next received the focus of our attention as Ed commenced the installation of the electrical wiring, single handed, covering the lighting, heating, sound, projection, computer network, Observatory video link, telephones, power cables for fans and power sockets. The dais was built and a host of cables pulled in through ducting from the Observatory via the control room to the dais. A contractor was brought in to cover the floor with heavy duty quality carpet, doors were fitted and painted, and exterior, interior as well as dome lighting installed by Ed.

An initial electrical survey by Ed had shown the inadequacy of the existing power supply to the Observatory to be utilised by the Planetarium, and having consulted the council's electrical engineers it was decided that it was necessary to dig a trench from Station House along the path of the Castle Eden Walkway via the Observatory to the Planetarium and lay a new electrical supply cable to meet present and future needs, and additionally telephone, computer network, astrophotography video and CCTV cables.

While the above work was proceeding, the salvaged seats from the cinema were brought to the Planetarium for stripping and cleaning. They were in a truly dreadful state and a working party of volunteers and their partners performed a minor miracle in cleaning and restoring the seats to a fit condition for installation. The seats were laid out in rows with provision for wheelchair access giving a minimum capacity of 72 people. They were also given a special fireproof coating to meet modern Health & Safety standards.

Jack Youdale created the frieze of silhouettes that cover the pelmet at the base of the dome. He chose a total of 32 local sites of interest and made black silhouettes of their outlines and stuck them on two metre lengths of opalescent Perspex which were fixed around the base of the dome forming a back illuminated pelmet. These included such famous landmarks as the Angel of the North, the bridges across the Tees and Roseberry Topping - have a go and see how many you can name!

Final plastering, painting, cleaning and installation of fittings went ahead as the volunteers worked seven days a week and evenings to complete the project in time for the official opening in November. Additional funding was also forthcoming, prior to opening, from Company Barclaycard to provide computers and an LCD data projector. In the event, the work was completed two weeks early and within budget (£90, 000) - a remarkable achievement considering the timescales involved and the cost of similar facilities constructed in the UK at this time!


The official opening took place on Friday the 9th of November 2001 when the guest speaker was Professor Allan Chapman (Astronomical Historian and fellow of Wadham College, Oxford University) who declared the Planetarium open. A second informal opening took place on the 26th of February 2002 when a long held promise was kept to invite back Suzannah Clarke (Soprano), Kate Wilson (Harpist), and the Thornaby Village Infants School children to give a second concert in celebration of the completion of the Planetarium. It was also the occasion of the first star show given in the building by John McCue.

The first computer network was also installed at this time by Ed using largely donated computers and some new equipment that John won in a competition. This allowed electronic communication with the outside world from all the computers on the network and a continuation of the participation in the Telescopes in Education scheme, for schools, by John and Ed. The initial publicity impetus for the launch came from a promotional leaflet designed by the SBC graphics department and the first joint Planetarium & CaDAS website, which was designed, written and maintained by Ed.

The Planetarium commenced operations in April, 2002 under its full time director John McCue and in its first full year of operation gave over 200 performances. Ed Restall became Planetarium Director in October 2005 The Planetarium now receives well over 10,000 visitors annually.


The project would not have been realised without the joint efforts of Stockton Council employees and the many CaDAS volunteers who freely gave up their time to make the dream become a reality. A full list appears below but special thanks go to the original project manager, Ron Peacock, his deputy Ed Restall and to Dave Lewis for their monumental efforts during the building phase of the project.

Martin Jenkins (Stockton Borough Council), Jack Coulthard, Paul & Pat Duggan, Sam Garside (Stockton Borough Council), Ray Haddow (Stockton Borough Council), Peter Kent, Dave Lewis, John McCue, Ian Miles Ron & Margaret Peacock, Charles Reece, Ed Restall, Mark & Linda Rice, Ken Stewart, Jack Youdale

Although not involved with the original construction, this article could not be written without mention of former CaDAS member Bob Mullen who was not only invaluable in helping to establish the early operational success of the Planetarium, but who was also instrumental to the bedding-in and development of all electrical and electronic systems within the facility.

This account is based upon an abridged version of an article written by Ron Peacock. Ron is a chartered mechanical engineer and former member of CaDAS who drew up the plans for the Planetarium and was very much involved in its creation.