Refracting telescope with equatorial mounting, Washington DC, USA, 1876.
© Science Museum / Science & Society Picture Library
Photograph of one the telescopes at the United States Naval Observatory in Washington when it occupied its original site at Foggy Bottom. This view shows an equatorially mounted refracting telescope of 24.5 cm (9.62 inch) aperture made by the German makers Merz & Mahler of Munich. The telescope was one of the original instruments installed at the observatory when it was completed in 1844.