Letter, from John Flamsteed to Henry Oldenburg, dated at Derby Encloses a paper of observations of Jupiter near fixed stars (see EL/F1/96); wishes for more apparatus to be able to rectify errors in Tycho's work and to add some stars to his catalogue; discussing the object glass for his telescope Read to the Royal Society on 7 May 1673 Edited version printed in 'Philosophical Transactions', vol 8, no 94, p 6033 19 April 1673