Keywords: Argelanderin refraktori 1.JPG en Argelander's refractor from ca 1820-1835 preserverd in Helsinki observatory western rotunda The two astronomical pendulum clocks are from 1760s-1780s left and ca 1823 right fi Argelanderin refraktori valmistettu noin 1820-1835 museoituna Helsingin observatorion länsirotundassa Kaksi astronomista heilurikelloa ovat 1760-1780-luvulta vasen ja noin vuodelta 1823 oikea own MKFI 2012-12-01 ImageNote 1 197 1154 770 2191 5184 3456 2 thumb ImageNoteEnd 1 Collections of the Helsinki Observatory Refracting telescopes 2012 in Helsinki December 2012 in Finland Taken with Canon EOS 60D Taken with Canon EF-S 15-85mm F3 5-5 6 IS USM Precision pendulum clocks Clocks in Finland Files by User MKFI |