The "Dodo-Postcards" watermark is NOT on the actual card – it is an online watermark only.
Greenwich Observatory. Galvano Magnetic Clock. Standard Time. Perkins. 1907
Royal Observatory. Greenwich. Perkins and Sons
Royal Observatory. Greenwich. Perkins. No. 41
Royal Observatory. Greenwich. Perkins. 1906
Greenwich. Royal Observatory. Perkins. Series No. C 44. 1916
Greenwich Park. London. Old Royal Observatory. The Greenwich Meridian. Longitude Zero crosses the Courtyard. Department of the Environment. Crown
Sussex. The Royal Greenwich Observatory. The Isaac Newton Telescope. J. Arthur Dixon. D. R. G. 1976
Sussex. The Royal Greenwich Observatory. The Isaac Newton Telescope. J. Arthur Dixon
