The idea of an 18 diameter Astronomical Telescope for Chesterfield was conceived in the 1950s by W. Horace Barnett, after he had successfully completed the engineering on a 12 instrument for Sheffield Astronomical Society. His dream acquired the reality of decision when he discovered that two Chesterfield members of the British Astronomical Association, Val Warburton, (a professional pianist) and Douglas Saunderson, were prepared to support him. Both were keen observers with their own instruments and Val Warburtons long experience in the making of astronomical mirrors offered a solution to the problem of obtaining optical parts.

With William Brown, then Joint Managing Director of Chesterfield Tube Company offering his personal support, as well as the support of his Company in the shape of raw materials and facilities, Horace Barnett at once began work on the heavy engineering parts, and interest in the idea mounted swiftly among his many friends and colleagues, interest which led to a large number of promises of half-a-crown a week donations for a year to finance the project. This enthusiasm led on the 17th November 1956 to the formation of The Chesterfield Astronomical Society and the election of Horace Barnett as Project Director.

Added momentum from the eighty members of the new society, and assistance from the local authorities, led not only to the lease of the Newbold site, but also in the offer of used bricks from a demolition programme.

An eighteen foot (5.5m) observatory with a hemispherical dome for the telescope and a fully equipped adjoining lecture room were designed by Peter F. R. Glossop, a professional architect who on joining the society offered his services. His design was accepted and in the Spring of 1957, members launched their first attack upon the spade work of the foundations.

With Horace Barnett setting a hectic pace, late summer saw not only the lecture room taking shape, but the pillar, headstock and main tube of the telescope assembled in position. The Society's achievements raised public interest, progress being closely followed in the local press, and an appeal to local concerns in the district raised over £400 in cash together with further help in valuable materials.

It was at this time that Val Warburton began his task of producing, by hand, a parabolic mirror 18 (450 mm) in diameter from plate glass only 37 mm thick. Working alone all winter in the new lecture room, he faced disappointment after disappointment and by spring 1958 had almost despaired of making such a thin disc to such fine tolerances. Being away for the summer season he left it unfinished, whilst work on the lecture room was completed and thoughts turned toward the last major constructional task. the dome.

William Brown, interesting himself in this problem, had meanwhile consulted Reynolds Aluminium Ltd., who dispatched one of their engineers to study the site and agree upon a workable design. The result was a donation to the Society from Reynolds Aluminium Ltd., of sufficient aluminium sheet and girders to completely build the dome.

In the autumn of 1958, Val Warburton renewed his attack on the mirror with the aid of a machine he and Horace Barnett had specially built for the job. Once more his efforts, even with the help of an eminent mirror maker, were unrewarded and it appeared that the glass was just too thin to be properly worked. Again he tried, working on his own and after much toil quite suddenly the miracle occurred and he had produced the figure he wanted. The great mirror was finished.

Meanwhile the circular observatory wall, built single-handedly by the society's eldest member Raymond G. Farmer, awaited the dome and Horace Barnett began construction of this during the summer of 1959, with such vigour, that only two months later it was revolving freely on its rollers. With the observatory weatherproof, work began on the installation of the optical components and final equipping of the telescope with its drive, finders and setting circles.

When the first successful observations were made in November 1959, just three years of hard work had elapsed between the idea and its attainment.

The Barnett Observatory housing the William Brown telescope was officially opened by the Astronomer Royal Dr. Richard van der Riet Woolley, O.B.E., M.A., M.Sc., Ph.D., Sc.D., F.R.S. on Saturday April 23rd 1960.