The Royal Observatory Edinburgh is open to the public on Saturday 24th and Sunday 25th September.

The observatory’s master clock supplied the time to the One o’ Clock Gun until the 1970s. The City Observatory on the Calton Hill is also open to the public on Saturday 24th September. Don’t miss this unique opportunity to visit both observatories which supplied the city's daily time signal to the One o’ Clock Gun and the Nelson Monument time-ball.

This week’s illustration shows Ralph Copeland the Astronomer Royal for Scotland who helped to set up the new Royal Observatory when it moved from the old building on the Calton Hill to the Blackford Hill in 1896.

Thomas Henderson Scotland's first Astronomer Royal is buried in Greyfriars cemetery.

He was succeeded by Professor Charles Piazzi Smyth who worked with Frederick James Ritchie and Chief Master Gunner Findlay to set up the One o' Clock Gun.