[1] Built in 1935, the observatory is classically styled in sandstone and has a distinctive 7 m dome, which houses a Victorian refracting telescope, a small planetarium, and display areas.

As a young man and a member of the Original Secession Kirk, he had been greatly influenced by the Reverend Thomas Dick, philosopher and author of a number of books on Astronomy and Christian Philosophy.

Dr Dick attempted to harmonize science and religion, and believed that the greatness of God could best be appreciated by the study of astronomy, to which he devoted his life after a period as an ordained minister at Methven.

However, the geography of Dundee is unique, in that it has Balgay Hill overlooking a river estuary, protected from the main lights of the city by trees which also help to provide a purer atmosphere, and at the same time very accessible to the public.

Professor Sampson collaborated with James MacLellan Brown, the City Architect, in designing a much more modern building than the one originally planned before the war.

The Observatory was formally opened by Professor Sampson on 28 October 1935, and presented to the Town Council by Mr. Milne of the Mills Trust in the presence of Lord Provost Buist.

Articles on current celestial objects were written in the local press by the Reverend John Lees, who usually acted as chairman at public lectures given at the Observatory by visiting astronomers The first Curator was J.

The 18-inch telescope was rarely used at full aperture, due to its tendency to be affected by reflections from street lights caused by the open lattice-work tube.

For this reason the Council placed the Observatory under the administrative control of the Parks Superintendent, under whom it remained until reorganisation brought a transfer to the Museums Department.

The expansion of the city north and west and the development of sodium and mercury street-lighting hampered the work of stellar photography, so in February, 1951 Bruce and Professor Freundlich suggested that the pilot telescope be transferred to St. Andrews University Observatory, eleven miles (18 km) to the south, for better conditions and proximity to the workshops.

Originally built in 1871 it was, at one time, privately owned by Walter Goodacre, president of the British Astronomical Association (BAA), who lived in the village of Four Marks, near Winchester.

In the autumn of 1952, the Observatory resumed its public functions under a new Curator, Jaroslav Císař DSc, FRAS, a research astronomer at St. Andrews.

Dr. Císař, from Czechoslovakia, soon aroused interest by his popular courses in astronomy at the adult education classes and encouraged young amateurs, including a number who became active in the Dundee Astronomical Society (DAS), which was formed a few years later.

In view of this, one of the keenest of the local amateurs, Harry Ford, a technician at Queen's College, became his assistant, and acted as Curator in Dr. Císař's absence.

The DAS became involved in work of the Observatory with the stimulation and encouragement given by Ford, who had inaugurated a programme for the instruction of the public using visual aids and experimental techniques.

Ford also organised displays of the work of the Observatory and the local Society at the BAA’s Exhibition Meetings in London, which excited great interest among the assembled amateurs, and resulted in many of them making a special journey to Dundee during their holidays.

This was the period of the great upsurge of interest due to the space spectaculars of the USSR and United States, culminating in the Apollo missions to the Moon.

In July 1969, during the period of the Apollo 11 landing on the Moon, the Observatory witnessed the largest gathering of people in its history, when a colour TV was installed in the lecture-room giving full coverage of the mission, interspersed with talks, slide-shows, and an exhibition, stewarded by members of the DAS.

Another significant event which stimulated local press interest was the expedition by Ford, Morgan Findlay and Dave Taylor to observe the 1973 total solar eclipse off the coast of Mauretania, as part of the BAA organised cruise on the ship "Monte Umbe", covered for the BBC by Patrick Moore and shown on his "Sky at Night" programme on television.

Possibly the greatest highlight of this entire period was the "Out of London" meeting of the BAA held on 25 September 1975 at the University of Dundee, which was organised by Harry Ford and the DAS, followed by a public lecture at night given by Patrick Moore on the subject of Mars.

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.

The following year saw the inauguration of great changes at the Observatory, the net result of which improved the structure and facilities in a marked way the installation of central heating, the re-surfacing of the balcony, the general redecoration of the whole building, and the upgrading of the lecture-room to an audio-visual theatre with carpeted flooring.

This, together with the development of the display area and sales section, was made possible by a grant from the Scottish Tourist Board, and meant the greatest upheaval since the Observatory was built.

Despite this the work of the Observatory continued uninterrupted and indeed it hosted a record number of booked parties and casual visitors, a tribute to the efforts of the Astronomer and her Assistant.

[4] In February 2024, there were plans for the observatory to close as a result of budget cuts proposed by Dundee City Council alongside Broughty Castle and the Caird Park golf course.

In response, a petition was created which led to over 3,000 signatures, and in June 2024, STAR-Dundee, a space technology company based in Dundee, committed £50,000 to the observatory which will be distributed over the course of five years.

[13] In February 2025, a lunar manuscript, The Moon – With a Description of its Surface Formations, which was donated to the observatory by Sir Patrick Moore in 1972, was put on display for the first time.

When the Mills Observatory opened on 28 October 1935, it originally housed a 450mm (18 inch) reflecting telescope, constructed by the Newcastle based company of Grubb Parsons.

On Balgay Hill, an outdoor planet trail, scale model of the Solar System, is arranged to entertain and educate the exploring visitor.

The main area in the centre of the building at ground floor level provides changing displays of pictures and models, and also houses the observatory shop.