An Account of the Eclipses or Ingresses of Jupiters Satellits into His Shadow and Such Emersions of them from It as will be Visible at the Observatory at Greenwich in the Three Last Months of This Year 1683. Sent in a Letter to the Publisher from J. F. Astron. Reg.

An account of the Eclipses or ingresses of Jupiter's Satellites into his shadow and such Emer- sions of them from it as will be visible at the Ob- servatory at Greenwich in the three last Months of this year 1683. sent in a Letter to the Publisher from J. F. Astron. Reg. SIR, I send you an account of the Eclipses or Ingresses of Jupiter's Satellites into his shadow, and such emersions of them from it as will be visible at the Observatory in the three last months of this year; they are calculated from new Tables I made this last summer, and I hope so exactly that the Ingresses of the first will seldom be found when observed, to differ above 5 minutes from the time stated, the 3 but little more; the Eclipses of the fourth and second I dare not promise you shall agree so well, for I find their motions evidently intangled with inequalitys, which it will require a long time and many more accurate observations to deter- mine and limit, then I have yet obtained: these Eclipses have been esteemed, and certainly are a much better expedient for the dis- covery of the Longitude than any yet known, by reason that they happen frequently, and are easily observable with a Telescope of 12. foot, or for need with one of 8. These Ingresses (and emersions also if visible) from the time till the opposition of the ☉ and ☿ happen truly on the right hand or in antecedence of the planet, but if they shall be observed with Telescopes of only two Convex glasses which invert the object, they appear on the contrary or left side of him. If these find acceptance with our ingenious friends the Eclipses of the next year shall be imparted early enough to be published in the December Transactions. I am SIR, yours, &c. J. FLAMSTEED. Observatory Sept. 22. 1683. The Ingresses of ye Satellites into his Shadow and Emergences of the third and fourth from it, visible at the Observatory in the months of October, November and December, 1683. October 9. Ingress of the 1. at 2. 50. Morn. 15. Ing. of the 4. at 7. 15. 16. Ing. 1. at 4. 43. 18. Ing. 2. at 3. 17. 23. Ing. 1. at 6. 37. 25. Ing. 2. at 5. 51. 31. Emergence of the 3. at 3. 42. November 1. Ingr. of the 4. at 1. 10. the 1. at 2. 59. Emer. of the 4. at 4. 52. 7. Ingr. of the 3. at 4. 10. Emer. of the 3. at 7. 38. 8. Ingr. of the 1. at 4. 49. 14. Ingr. of the 3. at 8. 05. 15. Ingr. of the 1. at 6. 40. 17. of the 1. at 1. 09. 19. of the 2. at 2. 44. 22. of the 1. at 8. 32. 24. of the 2. at 3. 00. 26. of the 2. at 5. 22. December 1. Ingr. of the 1. at 4. 50. Morn. 2. of the 1. at 11. 16. A. Noo. 3. of the 2. at 7. 47. Morn. 8. of the 1. at 6. 38. Morn. 10. of the 1. at 1. 06. Morn. 12. of the 3. at 11. 42. A. Noo. 13. and Emer. at 3. 40. Morn. 13. Ingr. of the 2. at 11. 32. A. Noo. 17. of the 1. at 2. 55. Morn. 20. Ingres. of the 3. at 3. 34. Morn. and Emer. at 7. 00. Morn. 21. Ingres. of the 2. at 2. 05. Morn. of the 4. at 6. 35. Morn. 24. Ingres. of the 1. at 4. 46. Morn. 25. the 1. at 11. 14. A. Noo. 28. the 2. at 4. 35. Morn. 31. the 1. at 6. 36. Morn.