The Astronomical Museum was set up in 1987 with the mission to preserve what remained of items used by the astronomers over the last two centuries. Many historical instruments had been scrapped or sold and others were being neglected.

The displays are of items interesting and/or historical. As many as space allows are shown. There may sometimes be a feeling of clutter, but what is the good of keeping things if they are never seen?

The Museum occupies the telescope building nowadays called the "McClean" after its donor, the noted British amateur astronomer, Frank McClean. As well as the telescope(s), there are a darkroom, a store room, an office and a laboratory. The last is now the main room of the Museum.

The collection is divided into themes that reflect the interests of the observatory over time. Most items are from the Royal Observatory period for the practical reason that the larger telescopes at Sutherland have accessories that are too large to display in a small place.