Observations of Immersions and Emersions of Jupiter's First Satellite, Made at Funchal, in Madeira, with a Reflecting Telescope of 18 Inches Focus, Made by Mr. Short. The Time Was Found by Taking Equal Altitudes, with a Quadrant of 12 Inches Radius, Made by Mr. Bird, and with the Help of a Good Pendulum Clock Made in London. By the Late Thomas Heberden, M. D. F. R. S.

XLI. Observations of Immersions and Emerisions of Jupiter's first Satellite, made at Funchal, in Madeira, with a reflecting Telescope of 18 Inches Focus, made by Mr. Short. The Time was found by taking equal Altitudes, with a Quadrant of 12 Inches radius, made by Mr. Bird, and with the help of a good Pendulum Clock made in London. By the late Thomas Heberden, M.D. F.R.S. Read Dec. 13, 1770. The latitude of the place of observation in Funchal, by a mean of several observations made with the same quadrant = 32° 33' 35". | Magnif. power | Apparent time | Obsr. made at Greenwich with a reflector of six feet focus, power 100 | Calculated in the Connoissance des temps | Diff. of Mer. between Madeira and Greenwich | |---------------|---------------|-------------------------------------------------|----------------------------------------|------------------------------------------| | | | Emerisions. | | | | 1763 Dec. 26 | 95 | 7 16 4 | 8 31 47 | 1 6 27 | | 1764 Jan. 11 | 95 | 5 27 35 hazy | 6 42 55 | 1 6 4 | | | 25 | 9 12 42 | 10 28 24 | 1 6 26 | | Feb. 10 | 55 | 7 29 47 | 8 45 34 | 1 6 31 | | | 17 | 9 25 12 flying clouds | 10 41 3 | 1 6 35 | | Mar. 27 | 55 | 8 9 3 clouds | 9 24 48 | 1 6 29 | | 1765 Dec. 24 | | 10 39 27 | | | | 1766 Jan. 16 | 55 | 9 31 20 | 10 47 48 | 1 7 12 | | Feb. 1 | 55 | 7 44 38 | 9 0 43 | 1 6 49 | | | | Emerisions. | | | | Mar. 5 | 55 | 6 37 36 doubtful | 7 45 5 | 1 6 36 | | 1767 Apr. 16 | 55 | 8 9 48 | 9 16 13 | 1 7 7 | | May 9 | 55 | 8 25 35 flying clouds | 9 32 26 | 1 7 37 | Observations Observations of Jupiter's first Satellite, made at Madeira. | Magnif. power | Apparent time | Obser. made at Greenwich with a reflector of six feet focus power 100 | Calculated in the nautical almanac | Diff. of Mer. between Madeira and Greenwich | |---------------|---------------|---------------------------------------------------------------------|-----------------------------------|------------------------------------------| | | | | | | | 1768 Mar. 26 | 55 | h ' " | | | | | | 8 26 51 | | | | Apr. 2 | | | | | | Apr. 18 | | | | | | 25 | | | | | | 27 | | | | | | May 4 | 55 | | | | | | | 7 19 24 | | | | | | 9 15 doubtful | | | | 11 | | | | | | 18 | | | | | | 20 | | | | | | 27 | | | | | | June 3 | | | | | | July 5 | | | | | Add for diff. of telescopes diff. of meridians N. B. 25" are to be allowed for the difference between the reflector used at Greenwich and that used at Madeira. 9' 16" are allowed for the difference of meridians between Paris and Greenwich. Diff. of the two mer. by the obf. of 16 April, 1767 1 6 25 1 6 50 1 6 55 1/2 mean.