Eclipses of Jupiter's First Satellite, the Eclipse of the Moon, and Occultations of Fixed Stars by the Moon. Observed at the Royal Observatory at Greenwich, in the Year 1769. Communicated by the Astronomer Royal

Read December 21, 1769. LV. Eclipses of Jupiter's First Satellite, the Eclipse of the Moon, and Occultations of Fixed Stars by the Moon. Observed at the Royal Observatory at Greenwich, in the Year 1769. Communicated by the Astronomer Royal. Apparent time. | Date | Time | Remarks | |--------|------|---------| | March 29 | 12 25 7 | with a 2 feet reflector of Short's constr. | | April 12 | 16 16 8 | with a 2 feet reflector of Bird's constr. | | April 28 | 14 35 17½ | with a 2 feet reflector of Short's. | | May 16 | 9 32 15 | with a 6 feet reflector of Short's. | | June 8 | 9 40 56 | with a 6 feet reflector of Short's. | | June 15 | 11 35 33 | with a 2 feet reflector of Short's. | | July 1 | 9 50 24 | Air a little hazy. Jupiter very clear. | ECLIPSE OF THE MOON. Observed with a 3½ feet achromatic treble object glass telescope of Dollond, with least magnifying power 30 times; and a 2 feet reflector of Short's, with least magnifying power 60 times. Apparent time. | Date | Time | Remarks | |--------|------|---------| | Dec. 12 | 16 57 13 | Beginning of eclipse. | | | 16 57 9 | The shadow first touches Kepler. | | | 17 3 3 | bisects ditto. | | | 17 3 33 | covers ditto. | Apparent Apparent time. | Dec. 12 | h | " | h | " | |---------|-----|-----|-----|-----| | | 17 | 9 | 19 | | | | 17 | 10 | 32 | 17 | | | 17 | 13 | 22 | | | | 17 | 15 | 54 | 17 | | | 17 | 16 | 56 | | | | 17 | 18 | 20 | | | | 17 | 20 | 1 | | | | 17 | 26 | 1 | 17 | | | | | | 26 | | | | | | 5 | The shadow touches Pytheas. covers ditto. covers Timochares. covers Archimedes. touches Eratothenes. covers ditto. bisects Copernicus. touches Mare Serenitatis. touches Manilius. covers ditto. touches Menelaus. covers ditto. touches Plinius. covers ditto. covers Dionyius. covers a spot between Plinius and Promont. Somnii. bisects a black spot surrounded by a white circle in Terra Mannae, lying in a leni joining Langrenus and Kepler. The observations in the first column were made by myself, with the 3½ f. achromatic telescope; and the others by my assistant W. Bayley, with the 2 f. reflector. OCCULTATIONS OF FIXED STARS BY THE MOON. Apparent time. | April 11 | h | " | |----------|-----|-----| | | 7 | 24 | | | 11 | | Em. of μ Geminorum, from the Moon’s bright limb. Certain to 5 or 10 seconds, with Dollond’s 3½ feet telescope. May 9 Em. of ξ Geminorum, from the Moon’s bright limb, with a 2 feet reflector. The true emersion is supposed to have been about 5 seconds sooner. Mean Mean time. Sept. 15 8 1 43.3 im. of 16 Piscium, at D's bright limb, with 6 f. reflector, certain to 1". between 10 22 47.3 and 49",3 with 6 feet refl. between 10 22 50.3 and 51",3 with 2 f. ref. by W. B. Sept. 20 10 28 19.6 im. of 1st x Tauri, with both telescopes exactly the same. 11 12 28.2 em. of 1st x Tauri, at D's dark limb, with 2 feet reflector. 11 16 54.5 em. of 2d x Tauri, with both telescopes exactly the same. Sept. 25 17 24 14.6 im. b Leonis, at D's bright limb, with 6 feet refl. 17 24 12.6 ditto, with 2 f. reflector, by W. B. The star was eclipsed to the north of the Moon's center, and the time seemed certain to less than a second, with both telescopes. Nov. 18 14 39 3.7 im. of 2d α Cancri, at D's bright limb, with 2 f. refl. Uncertain to 10". 15 5 49.3 em. of ditto, at D's dark limb, instantaneous, and the same with both telescopes.