Diagram for determining longitude
                                Date
                            
                            
                                9 May 1688
                            
                            
                        
                            
                            
                            
                                Creator
                            
                            
                                Unknown, Artist
                            
                            
                        
                            
                            
                            
                                Object type
                            
                            
                            
                        
                            
                            
                            
                                Archive reference number
                            
                            
                            
                        
                            
                            
                            
                                Manuscript page number
                            
                            
                                p328
                            
                            
                        
                            
                            
                            
                                Material
                            
                            
                            
                        
                            
                            
                            
                                Dimensions
                            
                            
                                height (page): 369mm
width (page): 232mm
                            
                        
                            
                            
                            width (page): 232mm
                                Subject
                            
                            
                            
                        
                            
                            
                            
                                Description
                            
                            
                                Diagram to help calculate longitude from the position of two stars. From a paper reviewing various methods for determining longitude by Edmond Halley, who proposed to the meeting of the Royal Society on 9 May 1688 that it would not be possible to determine longitude at sea without a complete theory of lunar motion.
This diagram is copied in RBC/7/389.
                            
                            
                        
                            
                            
                            This diagram is copied in RBC/7/389.
                                Object history
                            
                            
                                9 May 1688, 'Halley read a discourse of his own concerning the Longitude, being a full state of the case of that most famous problem, wherein he reckoned up the severall methods that have hitherto been used to discover it shewing the conveniencys and inconveniencys of each of them, and in what they are deficient. He concluded that it would be scarce possible ever to find the Longitude at Sea sufficient for Sea uses, till such time as the Lunar Theory be fully perfected' (JBO/8/205).
                            
                            
                        
                            
                            
                            
                                Related fellows
                            
                            
                                Edmond Halley (1656 - 1742, British) , Astronomer
                            
                            
                        
                            
                            
                            
                                Associated place