The site is enclosed by a boundary wall with a monument to John Playfair, president of the Edinburgh Astronomical Institution, in the southeast corner.

The oldest part is the Gothic Tower in the southwest corner, facing Princes Street and Edinburgh Castle.

[1] The City Observatory site was opened freely to the public for the first time on 24 November 2018 as Collective, a centre for contemporary art.

These were made available to build Short's observatory; and the City of Edinburgh provided a plot of land on Calton Hill.

James Craig designed the observatory, which, under Robert Adam's influence, was to look like a fortification with a wall and Gothic towers at its corners.

In 1850 this was removed[3] and she moved to Castle Hill, where her enterprise eventually became today's Camera Obscura on the Royal Mile.

In 1839 he published his results regarding the distance of alpha Centauri based on observations he had made 1832/33 at the Royal Observatory, Cape of Good Hope.

In 1846 Charles Piazzi Smyth became second Astronomer Royal for Scotland and set about reducing and publishing the backlog of Henderson's observations.

and his "The Red Lions", a dining club for younger members of the British Association, (named after the tavern where the first meeting was held), had occasion to run up to the observatory of Calton Hill for astronomical studies.

Accurate time was important for navigation, and mariners would bring ships' chronometers from the port of Leith up to Calton Hill for adjustment.

The 6-inch (15 cm) Cooke refractor was donated by William McEwan and installed in the dome on the Playfair Building.

[5] After Peck's death in 1925 his assistant John McDougal Field continued to run the City Observatory.

[7] The Council renovated Observatory House and the interior was restored by the Vivat Trust (a charity which aims to preserve old buildings) who let it as holiday accommodation.

In 2014, Collective relocated from their gallery in Cockburn Street, Edinburgh, opened an exhibition in the City Dome[14] and received an award of £900,000 from Creative Scotland to further develop the site.

[11][17] William Playfair's Observatory has been restored according to his surviving plans and the original Transit instrument is now on public display.