An Occultation of Jupiter and His Satellites by the Moon, October 28. 1740. in the Morning; Observed at Mr. George Graham's, F. R. S. House in Fleetstreet, London, by Dr. Bevis and Mr. James. Short, F. R. S.

Cassini, in his Astronomy, mentions much such another Observation. I likewise observed Two darkish Spots upon the Body of Venus; for the Air was exceeding clear and serene. XXIV. An Occultation of Jupiter and his Satellites by the Moon, October 28. 1740. in the Morning; observed at Mr. George Graham's, F. R. S. House in Fleetstreet, London, by Dr. Bevis and Mr. James Short, F. R. S. Times by the Clock, October 26. Apparent Times. October 27. Clock above Stairs. h. ' ". " 23. 46. 38. o. o. o. Clock below. 14. 49. 4. 15. 2. 25. The Sun's Centre passed the Meridian in the Transitory. The Moon's illuminate Limb preceded Jupiter in Right Ascension 1'. 38"'. in time. The same Limb preceded Jupiter 1'. 31"'. These were taken with a reflecting Telescope, 9 Inches | Clock above | h. ' " | h. ' " | |------------|--------|--------| | 15. 26. 1. | 15. 39. 20. | 9 Inches Focus, fitted with Wires at half Right Angles, and which magnified 30 times. | | 15. 37. 43. | 15. 51. 2. | Sirius passed the Meridian. The Moon's Centre passed the Meridian. Jupiter's Centre passed the Meridian. | | 15. 39. 9. | 15. 52. 28. | Jupiter's Third Satellite eclipsed by the Moon. Jupiter's Second Satellite eclipsed by the Moon. Jupiter's preceding Limb immersed. Jupiter's subsequent Limb immersed. Jupiter's First Satellite eclipsed by the Moon. These Immersions were taken with a Reflecting Telescope, of 16.5 Inches Focus, that magnified 120 times. Procyon passed the Meridian. The Sun's Centre passed the Meridian. | N. B. The Clock in the lower Room was all along 2" slower than the Clock in the upper Room. None None of the Emersions could be seen for Clouds. Whilst Jupiter was immerging, the Sky was perfectly serene; and, at his nearest Approach to the Moon, he did not appear to alter his Figure in the least, nor to be tinged with any prismatic Colours; neither did he (as is said to have been sometimes observed through refracting Telescopes) seem to enter at all upon the Moon's Body. That Part on the Moon's Limb where Jupiter entered, was a Hollow; and though some are of Opinion, that the Circumference of the Moon, as it is bounded to our Eye, is a perfectly smooth Circle, and that no Hills or Hollows appear there, as on the Surface of the Moon; yet if it be looked at in a clear Night with a good Telescope, that magnifies about 100 times, or even less, it will be seen rugged and uneven all round. Notwithstanding Jupiter's Light seems to be more vivid than that of the Moon, when he is seen at a good Distance from her, and far more so when the Moon is away; yet the contrary is plainly discerned when they are near one another: And in this Observation, whilst Jupiter was immerging behind the Moon, his Disk appeared much dimmer, and of a more faint and dusky Complexion, than the Disk of the Moon.