The "Dodo-Postcards" watermark is NOT on the actual card – it is an online watermark only.
Greenwich Planetarium. Old Royal Observatory. National Maritime Museum. Greenwich. Card No. 231. W. S. Cowell
Greenwich. National Maritime Museum. the Royal Observatory and Sir Christopher Wren Old Royal Naval College. Daraotsu. London A Z postcard
Greenwich. The Old Royal Observatory. National Maritime Museum. Larkfield Printing
National Maritime Museum. Greenwich. Old Royal Observatory. Time Ball and 24 Hour Clock. Crown
Greenwich. National Maritime Museum. Old Royal Observatory. Artisan Press. England. No. 239
National Maritime Museum. 2004 stamp. Royal Observatory Greenwich
