During this period also the public work of the Observatory received a great boost, with many more visitors and parties of children and adults. Particular use of the facilities was made by school classes and youth groups. Ford extended the Observatory's displays by construction of many models including various space-crafts. He was also responsible for an important addition to the Observatory's facilities, namely the 12-seat planetarium or artificial sky, which he built himself from various oddments, and which proved a great attraction in its own right, particularly for the younger visitors, and for school parties. Although it has now been supplemented by a commercially-made planetarium which can accommodate larger parties, Ford's original planetarium is still used regularly for small groups of visitors. Dick Kennedy, the longest-serving caretaker of the Observatory, who began after McDonald left in the 1950s and continued until his retirement in 1973. He was succeeded as caretaker by Jim Richardson, who retired the following year.