Astronomical Observations by the Missionaries at Pekin. Transmitted to the Supra-Cargoes at Canton, by the Rev. Father Louis Cipolla, of the Tribunal of Mathematics, and Communicated to the Royal Society by the Court of Directors of the East-India Company

II. Astronomical Observations by the Missionaries at Pekin. Transmitted to the Supra-cargoes at Canton, by the Rev. Father Louis Cipolla, of the Tribunal of Mathematics, and communicated to the Royal Society by the Court of Directors of the East-India Company*. PREFACE, BY THE ASTRONOMER ROYAL. Redde, Nov. 4, 1773. Most of the following Observations appear to have been made with a telescope of eight feet, to which a micrometer, for measuring differences of right ascension and declination was occasionally adapted. There was besides another telescope of eight feet, consisting of two object-glasses, in the manner of Röemer, which might be brought nearer together or separated, in order that the moon's diameter might completely fill a fine reticule, in the focus, divided into twelve equal parts, for measuring the digits eclipsed in lunar eclipses. It is mentioned in the account of the lunar eclipse of Nov. 12, 1761, that * The Society was favoured with another copy of these Observations by John Blake, Esq. of Parliament-street, to whom they were transmitted by his son John Bradby Blake, Esq. Supra-cargo at Canton. the clock was regulated by a transit instrument. It is therefore probable, it was regulated in the same manner in all the succeeding observations, which consist of the following particulars. 1. Observations of the last transit of Venus over the Sun, viz. of differences of right ascension and declination between Venus and the Sun, and the internal and external contact of the limbs at the egress. It is however remarked, that the clock was counted by a person, who was sometimes found to make mistakes. 2. The eclipse of the Sun, May 25, 1770. The beginning and end were observed, and the lucid parts measured, during the eclipse, with the micrometer. 3. The beginning and end of the eclipse of the Moon, Oct. 23, 1771. 4. Emergence of Jupiter from occultation by the Moon, July 5, 1770. 5. An Occultation of Spica Virginis by the Moon; the immersion and emergence both observed, Jan. 25, 1772. 6. The occultation of a star in Scorpio by the Moon; the immersion and emergence both observed. 7. The observation of Venus in the Sun's parallel, Jan. 5, 1772, by taking the difference of right ascension and declination of Venus and the Sun. 8. The total eclipse of the Moon, Nov. 12, 1761. The beginning, total immersion, emergence, and end, were observed by three different observers, with telescopes of 5, 7, and 8 feet, in the domestic observatory. vatory of the College of the Jesuits; where also all the former observations were made. The same eclipse was also observed at the Royal Observatory at Pekin, 14" west of the Jesuit's College, with a telescope of 8 feet, composed of two object-glasses, with a reticule at the focus, divided into 12 equal intervals for measuring the digits eclipses, in the manner of Röemer. It is remarked, that the leaf, in which this observation was recorded, had been lost, and was found again, Oct. 12, 1772: on which account this observation was never transmitted to Europe before. NEVIL MASKELYNE. Transitus & infra discum ⊙, die 4 Junii, anni 1769. Pekini, in residentiā S. Josephi, tubo 8 pedum, observatus. Temp. ver. mat. | h | m | s | Description | |---|---|---|-------------| | 4 | 42 | 5 | limbus occ. ⊙ ad horarium | | 4 | 44 | 21 | limb. ort. ⊙ ad hor. | | 2 | 16 | | mora diametri ⊙ - - - - 31 38 | | 4 | | | mora diam. ⊙ - - - - 56 | | 4 | 54 | 39 | limb. occ. ⊙ ad hor. | | 4 | 55 | 55 | centr. ⊙ ad hor. | | 1 | 16 | | ⊙ à limb. bor. ⊙ - - - - 5 5 | | 5 | 19 | 36 | limb. occ. ⊙ ad hor. | | 5 | 20 | 45 | cent. ⊙ ad hor. | | 1 | 9 | | ⊙ à limb. bor. ⊙ - - - - 5 30 | | 5 | 24 | 44 | limb. occ. ⊙ ad hor. | | 5 | 25 | 52 | cent. ⊙ ad hor. | | 1 | 8 | | ⊙ à limb. bor. ⊙ - - - - 5 35 | | 5 | 53 | 30 | limb. occ. ⊙ ad hor. | | 5 | 54 | 30 | cent. ⊙ ad hor. | | 1 | 0 | | ⊙ à limb. bor. ⊙ - - - - 6 18 | | 5 | 57 | 50 | limb. occ. ⊙ ad hor. | | 5 | 58 | 49 | cent. ⊙ ad hor. | | 59 | | | ⊙ à limb. bor. ⊙ - - - - 6 36 | | 6 | 2 | 56 | limb. occ. ⊙ ad hor. | | 6 | 3 | 53 | cent. ⊙ ad hor. | | 57 | | | ⊙ à limb. bor. ⊙ - - - - 6 44 | | 6 | 42 | 16 | limb. occ. ⊙ ad hor. | | 6 | 43 | 3 | cent. ⊙ ad hor. | | 47 | | | ⊙ à limb. bor. ⊙ - - - - 7 25 | Temp. Temp. ver. mat. 6 51 42½ limbus occ. ⊙ ad horarium 6 52 27 centr. ⊙ ad hor. 44 ⊙ à limb. bor. ⊙ - - - - 7 28 7 0 2 limb. occ. ⊙ ad hor. 7 0 44 cent. ⊙ ad hor. 42 ⊙ à limb. bor. ⊙ - - - - 7 18 7 4 7½ limbus occ. ⊙ ad hor. 7 4 48 cent. ⊙ ad hor. 40½ ⊙ à limb. bor. ⊙ - - - - 7 24 7 7 13 limbus occ. ⊙ ad hor. 7 7 53 cent. ⊙ ad hor. 40 ⊙ à limb. bor. ⊙ - - - - 7 25 7 15 53 limbus occ. ⊙ ad hor. 7*18 31 cent. ⊙ ad hor. 38 ⊙ à limb. bor. ⊙ - - - - 7 33 7 52 36 limbus occ. ⊙ ad hor. 7 53 4 cent. ⊙ ad hor. 28 ⊙ à limb. bor. ⊙ - - - - 8 10 7 58 5½ limbus occ. ⊙ ad hor. 7 58 32 cent. ⊙ ad hor. 26½ ⊙ à limb. bor. ⊙ - - - - 8 14 8 3 2 limbus occ. ⊙ ad hor. 8 3 28 cent. ⊙ ad hor. +25½ ⊙ à limb. bor. ⊙ - - - - 8 24 * The same in both the manuscripts. But there must be an error either in this number, or that next above. S. Horsley. † The manuscripts still agree. The error probably lies upon the number next but one preceding, viz. the time of the appulse of the ⊙'s west. limb to the hor. wire; which may have been 8 3 2½. S Horsley. Temp. ver. mat. 8 6 4½ limbus occ. ⊙ ad horarium 8 6 29 cent. ♀ ad hor. 24½ ♀ à limb. bor. ⊙ - - - - 8 38 8 24 28½ limbus occ. ⊙ ad hor. 8 24 48 cent. ♀ ad hor. ‡29½ ♀ à limb. bor. ⊙ - - - - 8 50 8 26 2 limbus occ. ⊙ ad hor. 8 26 21 cent. ♀ ad hor. 19 ♀ à limb. bor. ⊙ - - - - 8 58 9 6 50 Videtur ♀ prolongari, ac velut radios emittere offuscantes limbum facie occidentali Solis. 9 7 32 Contactus interior circularis. 9 22 8 limbus ort. ♀ ad horarium. 9 24 19 limbus ort. ⊙ ad hor. 2 11 ♀ à limb. bor. ⊙ - - - - 9 54 9 26 32 Egref. tot. ♀ à ⊙. Amice rogatus observationem hanc communem facio, quamvis non nimis confidam, ejus praesertim causā, qui horologio aderat, et quem in notando tempore minus fidelem aliquando deprehendi. Eclipsin ⊙ hāc ipsā die spectandam nubes eripuere. † The manuscripts agree: but the error is manifest. Read 29½. S. Horsley. Eclipsis Eclipsis ☉, die 25 Maii, anni 1770. Pekini, in residentiâ Sancti Josephi, tubo 8 pedum, observatâ. Temp. ver. Diam. ☉ capta plur. = 33\(\frac{1}{4}\) Rev. = 31 35 44 7 31 7 Cœperat Eclipse. 7 31 0 Init arbitratum. Pars ☉ illuminata. | Temp. | ☉ | |-------|---| | 7 38 11 | 29 25 35 | | 7 39 34 | 27 54 21 | | 7 40 40 | 27 27 44 | | 7 42 23 | 26 47 6 | | 7 43 45 | 26 10 40 | | 7 45 14 | 25 56 40 | | 7 46 21 | 25 32 31 | | 7 47 49 | 25 7 37 | | 7 49 25 | 24 42 24 | | 7 50 30 | 24 11 34 | | 7 51 59 | 23 35 8 | | 7 54 32 | 22 50 19 | | 7 55 47 | 22 36 18 | | 7 57 25 | 22 19 29 | | 7 58 26 | 21 51 28 | | 7 59 29 | 21 37 27 | | 8 0 36 | 21 16 26 | | 8 1 52 | 21 1 1 | | 8 2 57 | 20 44 13 | | 8 4 18 | 20 30 11 | | 8 5 25 | 20 23 11 | | 8 6 42 | 20 9 10 | Temp. | Temp. ver. | Pars o illuminata | |-----------|-------------------| | h | ' " " " | | 8 7 49 | 19 42 33 | | 8 9 35 | 19 32 45 | | 8 10 49 | 19 1 56 | | 8 13 1 | 18 58 44 | | 8 13 56 | 18 54 56 | | 8 15 30 | 18 39 31 | | 8 16 55 | 18 32 30 | | 8 18 20 | 18 31 6 | | 8 20 30 | 18 29 42 | | 8 21 33 | 18 24 6 | | 8 23 2 | 18 28 18 | | 8 25 30 | 18 38 6 | | 8 27 12 | 18 40 55 | | 8 28 30 | 18 47 55 | | 8 35 34 | 19 21 33 | | 8 37 58 | 19 36 57 | | 8 39 24 | 19 41 9 | | 8 41 16 | 19 48 9 | | 8 44 14 | 19 55 10 | | 8 46 47 | 21 2 25 | | 8 48 2 | 21 22 2 | | 8 49 16 | 21 31 51 | | 8 50 26 | 21 48 40 | | 8 52 37 | 22 2 40 | | 8 56 42 | 23 51 57 | | 8 58 19 | 24 42 24 | | 9 0 17 | 25 7 37 | | 9 1 41 | 25 17 26 | | 9 2 58 | 25 24 27 | | 9 5 52 | 26 44 18 | Temp. Temp. ver. Pars o illuminata. 9 7 42 - - - - - - - 27 29 8 9 9 27 - - - - - - - 27 55 45 9 10 49 - - - - - - - 28 13 59 9 12 6 - - - - - - - 28 33 36 9 13 44 - - - - - - - 29 7 13 9 14 52 - - - - - - - 29 17 2 9 17 34 - - - - - - - 30 48 6 9 19 52 Finis Eclipseos. Eclipsis τ, die 23 Octob. anni 1771. Pekini, in residentiâ S. Josephi, per me ægrotum observata. 11 22 6 Init. Eclipseos. 13 37 13 Finis. Maximam Eclipse non notavi. à tectus, die 5 Julii 1770. Pekini, in residentiâ Sancti Josephi, tubo 8 pedum, observatus. Ingressum non observavi, tarde accedens ad observandum. Temp. ver. | h | m | s | |---|---|---| | 7 | 57 | 29 | | 7 | 59 | 59 | | 8 | 10 | 6 | | 8 | 11 | 20 | | 1 | 14 | Tych. à limb. bor. | | 8 | 18 | 20 | | 8 | 19 | 34 | | 1 | 14 | Tych. à limb. aust. | | 8 | 25 | 56 | | 8 | 27 | 26 | | 1 | 30 | | | 8 | 36 | 3 | | 8 | 36 | 46 | | 1 | 43 | * | | 8 | 45 | 20 | | 8 | 47 | 9 | | 1 | 49 | | | 8 | 53 | 27 | | 8 | 55 | 29 | * The manuscripts agree. It is uncertain, whether the error be upon the number next preceding, or the next but one. S. Horsley. Temp. | Temp. ver. | h | m | s | |-----------|---|---|---| | | | | | | 8 | 59| 3 | u | | 9 | 1 | 15| T | | | 2 | 12| - | | | 9 | 12| 24| u | | | 9 | 14| 40| T | | | | 2 | 16| - | | | 9 | 19| 11| u | | | 9 | 21| 46| T | | | | 2 | 36| - | | | 9 | 28| 29| u | | | 9 | 31| 22| T | | | | 2 | 53| - | | | 9 | 34| 19| u | | | 9 | 37| 20| T | | | | 3 | 1 | - | | | 9 | 14| 56| u | | | 9 | 45| 9 | T | | | | 3 | 13| - | | | 9 | 52| 49| u | | | 9 | 56| *7| T | | | | 3 | 28| - | | 10 | 5 | 6 | u | | 10 | 8 | 53| T | | | | 3 | 47| - | | 10 | 14| 37| u | | 10 | 18| 37| T | | | | 4 | 0 | - | * It is so in both the manuscripts, but if the numbers next above and next below be right, this ought to be 17. S. Horsley. Vol. LXIV. G Adde Adde sequentes observationes eodem tubo per me factas. In residentiâ Sancti Josephi. * Spic. Virg. a tecta, d. 25°. Jan. 1772. Ingr. 5h 27' 41'' t.v. * a limb. bor. c 29 2 Egr. 6 34 07 * a limb. bor. c 19 30 Capta diameter. 32 29 In residentiâ Sancti Josephi. * Scorp. a tecta, d. 29°. Jan. 1772. Ingr. 4h 16' 35'' t.v. * a limb. aust. c 13 0 Egr. 5 33 31 * a limb. aust. c 20 9 Capta diameter. 31 53 In collegio Pékin. § in parallelo o d. 5°. Jan. 1772. diam.o 6h 35' 47'' limb. ort. o ad hor. 31 44 φ 55 05 § ad hor. à parallel. limb. bor. 22 11 3 16 13 diff. atc. diff. decl. 9 33 Eclipsis Eclipsis Lunæ totalis, anno 1761, Novembris 12°, vespere observata, Pekini Sinarum. In Observatorio domestico Collegii Soc. Jesu. | | P. Florian Bahr. | P. Ignatius Francisci. | P. Josephus Bernardo | |----------------------|------------------|------------------------|---------------------| | Tubo 5 pedum | Tubo 7 pedum. | Tubo 8 pedum. | | h ' " | h ' " | h ' " | | Initium Eclipseos | 5 29 12 | 5 28 4 | 5 29 3 | | Immers. tot. Lunæ | 6 28 59 | 6 24 33 | 6 27 18 | | Init. emers. Lunæ | 8 2 37 | 8 7 2 | 8 4 23 | | Finis eclipseos | 9 4 32 | 9 4 42 | 9 3 52 | | Medium. ex init. | 7 16 52 | 7 16 23 | 7 16 27 | | et fine | | | | | Med. ex immer. | 7 15 48 | 7 15 47 | 7 15 50 | | et emers. | | | | | Et horum med. | 7 16 20 | 7 16 5 | 7 16 8 | | Ex his confit med. | | | | | eclipseos | 7 16 11 | | | Et observata sunt hæc ad pendulum, quod quotidie ad solem et stellas exigitur, telescopio meridianó, quod, vocant “l’instrument des passages.” In Observatorio Regio, tubo 8 pedum cum duobus objectivis et reticulo. | Initium eclipseos | Initium Emerf. | |------------------|---------------| | Digit. umbræ I. | Digit. lucis I. | | II. | II. | | III. | III. | | IV. | IV. | | V. | V. | | VI. | VI. | | VII. 6 | VII. | | VIII. | VIII. | | IX. | IX. | | X. | X. | | XI. | XI. | Immerf. Lunæ tot. 27 o | Finis eclips. 5 o Ex his conficitur medium eclips. 7 16 20 Atqui constat observatorium regium orientalius esse collegio 14'' pend. Observata sunt hæc ad horologium manuale bonæ notæ, quod ante cum eodem pendulo compositum, et post cum illo collatum sibi probe constitit, uti alias solet. Tempora Tempora sunt vera omnia. Numeri ab observatione intacti. Coelum toto tempore serenum fuit, et quietum a vento; umbra tamen terrae admodum non terminata, praesertim initio: Luna in umbra semper clare visa tota, margine bene terminato; quin tamen maculae distinguerentur. Color Lunae instar ferri candentis; post immersionem obscurior, et ante emersionem obscurior, qua axem umbrae, in medio umbrae obscurior, qua centrum terrae spectabat. Paullo ante initium emersionis visa stellula sic satis lucida, verticaliter Lunae imminens, nempe in tubo situ inverso, distans a limbo Lunae quasi 3 diametri; et spes erat videndi hujus occultationem, antequam eclipsis finiret: sed vix digitus unus Lunae emersit, cum lumine Lunae extincta videri desit. Porro, | Medium Eclipsos dabant | D. Halleii | 7 | 20 | 56 | |------------------------|------------|----|----|----| | | D. Cassini | 7 | 23 | 20 | | tab. | P. Gramatis| 7 | 22 | 26 | | Institit. Astron. D. Monnier | 7 | 15 | 39 | | Ephemerides Parisientes, necesse ex quibus tabulis | 7 | 33 | 33 | Ad merid. Collegii hujus. Folium, in quo praesens observatio erat notata, perditum fuerat, et, die 19 Octobris anni 1772, calu inventum; adeoque haec observatio eclipses Lunae nunquam in Europam fuit missa.