Imagine having an equatorial observatory built for you on your 16th birthday as a present from your father. That’s what happened to Thereza Dillwyn Llewelyn at Penllergare in 1851.

Equatorial ObservatoryFather and daughter were enthusiastic astronomers and it was from here they made one of the first photographs of the moon (c.1857/8). So what did the equatorial observatory look like and how did it work?

There was a stone rotunda building capped by a wooden, copper-clad drum. This revolved on metal rollers pulled by a chained gearing system.

ScienceHalfway across the diameter of the drum was a top shutter. There was also another on the side through which the telescope could be pointed.The inside walls were lined with hollow clay bricks for the dual purpose of retaining heat and preventing vibrations; and the telescope rested on a central pillar within a pit surrounded by an elevated wooden floor.

We believe the adjoining lower room was used as a laboratory and photographic darkroom.

Today it is one of the few remaining original structures on the estate. It has unfortunately fallen into a rather poor condition but you’ll be pleased to hear that we are repairing the observatory in early 2015.

Thereza Dillwyn Llewelyn

Thereza Dillwyn Llewelyn. Photo by John Dillwyn Llewelyn (19th century)


With his fervent interest in scientific invention, John also became involved, with the engineer Benjamin Hill of Clydach, in the design of an electrically powered boat. A small motor was tried out at his brother Lewis’s laboratory in 1841 and John went on to design a larger version that he fitted to one of his boats and demonstrated on the Upper Lake at Penllergare. He assisted Sir Charles Wheatstone with experiments of electrical underwater telegraphy off Mumbles Head and an electric bell between the lodge and Sketty Hall.

Learn more about the photographer of Penllergare