Astronomical Observations Made at Cavan, Near Strabane, in the County of Donegal, Ireland, by Appointment of the Royal Society, by Mr. Charles Mason

XXXIX. Astronomical Observations made at Cavan, near Strabane, in the County of Donegal, Ireland, by Appointment of the Royal Society, by Mr. Charles Mason. Read November 7, 1770. Equal Altitudes of the Sun and Stars. | Time per Clock of the equal Altitudes of the O's limbs, and of *'s. | Zen. distance or points on the limb of the quadrant the nonius was set at. | O's Limb, and Stars observed. | Time per Clock when the O's cent. and * passed the merid. from the mean of the Observations. | |---|---|---|---| | **1769 April** | | | | | **3** | 7 51 11½ | 1st wire | Arcturus | | | 54 45 | middle wire | | | | 58 15 | 3d or last wire | | | | | | 64 56 | | | 7 30 7 | | Ditto. | | | 33 41+ | | | | | 37 14- | | | | | | | 59 20 | | | 9 20 14 | | Spica | | | 25 36 | | | | | 31 1½ | | | | | | | 72 40 | | **4** | 7 47 46 | | Arcturus | | | 51 19 | | | | | 54 49+ | | | | | | | 64 56 | | | 8 26 43 | | Ditto | | | 30 17½ | | | | | 33 49½ | | | | | | | | | | 9 16 49 | 2 41 59 | Spica | | | 22 11 | | | | | 27 37+ | 31 11½ | | | | | | 72 40 | | | 9 43 35+ | 2 15 10 | Ditto | | | 49 49 | 8 56+ | | | | 56 11 | 2 35 | | | | | | 70 15 | | | | | | 11 59 23¾ | ### Equal Altitudes of the Sun and Stars | Date | Time per Clock of the equal Altitudes of the limbs, and of *'s. | Zen. distance or points on the limb of the quadrant. the nonius was set at. | O's Limb, and Stars observed. | Time per Clock when the O's cent. and * passed the Merid. from the mean of the Observations. | |------------|---------------------------------------------------------------|--------------------------------------------------------------------------|-------------------------------|----------------------------------------------------------------------------------| | 1769 April | | | | | | 8—5 | h ' " | h ' " | o ' " | Arcturus. | | | | 8 23 16½ | 26 50 | 30 21½ | | | | | 9 13 23 | 2 38 30 | 18 47 | 33 7 | Spica | | | 24 11 | 27 41 | | | | | | 9 40 8+ | 2 11 44+ | 46 23½ | 5 30+ | Ditto | | | 52 44 | 1 59 9 | | | | | 7—8 | 9 36 6½ | middle wire | | | Spica | | 9—10 | 9 11 30 | 2 18 16½ | Clouds | 44 55 | O's upp. limb | | | 21 12½ | 8 33 | | | | | | 21 33 | 2 8 13½ | 26 32½ | 3 14½ | O's low. limb | | | 9 34 36 | 1 55 15 | Clouds | 54 55 | | | | 45 31½ | 52 35 | | | O'u pp. limb | | | 51 38 | 1 38 7: | Ditto | | O's low. limb | | | 8 6 9+ | | | | Arcturus | | | 9 44½ | | | | | | | 13 16 | | | | | | | 9 23 3 | 1 54 35 | Clouds | 70 15 | Spica | | | 29 16 | 1 42 0 | | | | | | 35 38 | | | | Arcturus | | 8—12 | 7 59 18½ | | | | Arcturus | | | 8 2 53 | | | | | | | 6 25 | | | | | ### Equal Altitudes of the Sun and Stars. | April 1769 | Time per Clock of the equal Altitude of the O's Limbs, and of *'s. | Zen. distance or points on the limb of the quadrant, the nonius was set at. | O's Limb, and Stars observed. | Time of Clock when the O's cent. and * paired the merid. from the mean of the Observations. | |------------|---------------------------------------------------------------|-----------------------------------------------------------------|-----------------------------|----------------------------------------------------------------------------------| | 8—12 | 8 49 25+ 54 46 9 0 13 | Cloudy at the time corresponding | 72 40 Spica | | | 24—20 | 7 47 1 50 50½ 54 33½ | 3 47 46 43 59 40 16 | 62 36 O's upp. limb. | | | | 8 6 27½ 10 17½ 14 11 | 3 28 24 24 29 20 38½ | 60 00 Ditto | | | | 8 31 58½ 36 6 40 9 | 3 2 48½ 3 58 44 54 38½ | 56 42 Ditto | | | | 44 32½ | 2 50 19 | O's lower limb | | | | 7 35 23 38 56 | | 59 20 Arcturus | | | 2—21 | 7 28 23 31 58+ 35 30 | | 59 20 Arcturus | II 1 3¾ | | | 7 59 31 8 4 22½ | 2 7 28 2 35 1 57 43½ | 75 5 Sipca | | | | 8 18 28½ 23 52 29 18 | 1 43 39 1 38 16 | 72 40 Ditto | | | h—22 | 8 45 48 49 48 53 44 | | 48 12 Arcturus | | | | 10 2 37 8 7—13 44 | | 39 25 Ditto | | ### Equal Altitudes of the Sun and Stars. | Date | Time per Clock of the equal Altitudes of the O's limb, and of *'s. | Zen. distance of points on the limb of the quad. the nonius was set at. | O's limb, and Stars observed. | Time per Clock when the O's cent.and * passed the merid. from the mean of the Observations. | |------------|------------------------------------------------------------------|-----------------------------------------------------------------|-------------------------------|----------------------------------------------------------------------------------| | 1769 April | | | | | | 3—25 | h ' " | o ' " | Arcturus | | | | 8 35 33 :: | 48 12 | | | | | 39 27 | | | | | | 43 25 | | | | | | 8 52 53 | | Ditto | | | | 57 2 | | | | | | 9 1 11 | | | | | | 9 52 17 | | Ditto | | | | 57 48 | | | | | | 10 3 25 | | | | | 8—26 | h ' " | o ' " | Arcturus | | | | 8 49 29+ | 2 22 11 | | | | | 53 39 | 18 1½ | | | | | 57 47½ | 13 53 | | | | | 9 48 57 | | Ditto | | | | 54 28 | | | | | | 10 0 5 | | | 11 35 50,2 | | 8—28 | h ' " | o ' " | Arcturus | | | | 8 | 46 00 | | | | | 8 46 47 | | | | | | 50 52:: | | | | | | 9 7 51 | 1 50 4 | Ditto | | | | 12 26 | 45 29 | | | | | 16 59 | 40 55 | | | | | 9 42 5 | | Ditto | | | | 47 35 | | | | | | 53 12 | | | | | 9—30 | h ' " | o ' " | Arcturus | | | | 12 5 9 | 40 51 | | | | | 10 11 | | | | | | 15 19 | | | | | | 12 23 11½ | | Ditto | | | | 28 52½ | | | | | | 34 40 :: | | | | **N.B.** This day I screwed the bob of the pendulum 7 revolutions and 17 divisions (of the nut) and set the clock at noon to nearly sidereal time. ### Equal Altitudes of the Sun and Stars. | Date | Time per Clock of the equal Altitude of the O's limb, and of *'s. | Zen. distance of points on the limb of the quadrant. the nonius was set at. | O's limb, and Stars observed. | Time per Clock when the O's cent. and * passed the merid. from the mean of the Observations. | |------|---------------------------------------------------------------|-----------------------------------------------------------------|-----------------------------|----------------------------------------------------------------------------------| | 1760 May 2 | 12 9 50½ 14 57 | 40 51 | Arcturus | | | | 12 4 26 9 28 14 32½ | 40 51 | Arcturus | | | | 12 28 9+ 33 57 | 39 5 | Ditto | | | 3 | 12 4 4 9 5½ 14 11 | 16 7 14 16 2 11+ 15 57 5½ | 40 51 | Arcturus | 14 5 38,9 | | | 12 27 46 33 36 | 15 43 32 37 43½ | 39 5 | Arcturus | | | 6 | 12 2 55+ 7 58 13 3½ | 40 51 | Arcturus | | | | 12 20 58 26 38 32 27— | 39 5 | Ditto | | | 10 | 12 39 28½ 25 9 30 58 | Cloudy at the time corresponding | 39 5 | Arcturus | | | 15 | 12 17 40 23 19 29 9 | Clouds Clouds 15 33 15 | 39 5 | Arcturus | 14 1 12,0 | | 18 | 11 58 30 12 3 31 8 37+ | 16 1 40 15 56 41½ | 40 51 | Arcturus | 14 0 5,0 | | 24 | 1 2 58 7 3 11 4½ | 6 54 38— 5° 33+ | 46 24 | O's supp. limb | | Clouds Equal Altitudes of the Sun and Stars. | Time per Clock of the equal Altitudes of the O's limb, and of *'s. | Zen. distance of points on the limb of the quadrant, the nonius was set at. | O's limb, and Stars observed. | Time per Clock when the O's cent. and * passed the merid. from the mean of the Observations. | |---|---|---|---| | **May** | | | | | 1766 | | | | | 24 | 1 21 4 | Clouds | 3 58 39.2 | | | 25 23½ | 6 32 10½ | 44 10 O's upp. limb | | | 29 40 | 6 27 55 | O's low. limb | | | 34 16½ | 6 23 19½ | | | 31 | 0 4 30 | 8 44 40 | 4 24 27.0 | | | 8 7 | 41 4 | 56 58 O's upp. limb | | | 11 39 | 37 30 | O's low. limb | | | 15 22½ | 33 48½ | | | | 12 45 40 | The O's last limb set over a hill, at the distance of about 3½ or 4 miles. | | | | 14 46 10— | | 38 17 | | | 49 44 | | | | | 53 14+ | | | | 15 | 12 47 | | Ditto | | | 16 24— | | | | | 19 56 | | | | | 15 36 15+ | Cloudy | | | | 39 51: | 19 42·45 | 18 20 Draconis a * 2d mag. merid. z.d. 3° 19' 38" | | | 43 19½ | 39 16 | | | | 49 8½ | 19 33 27 | 17 41 17.5 | | | 52 42 | 29 53 | | | | 56 11 | 26 23 | | | **June** | | | | | 24—1 | 0 14 38 | | 55 57 O's upp. limb | | | 18 14½ | | | | | 21 47 | | Ditto low. limb | | | 25 30 | | | | | 0 30 10 | | 53 45 O's upp. limb | | | 33 49½: | | | | | 37 27½ | | Ditto low. limb | | | 41 14 | | | N.n.n.2 ### Equal Altitudes of the Sun and Stars | Time per Clock of the equal Altitudes of the Sun's limb, and of *'s. | Zen. distance of points on the limb of the quadrant, the nonius was set at. | Stars observed. | Time per Clock when the Sun's cent. and * passed the merid. from the mean of the Observations. | |---|---|---|---| | **1769 June** | | | | | 24—1 | h ' " | h ' " | | | 1 | 6 31½ | 48 45 | Sun's upper limb | | 10 | 20 | | Ditto lower limb | | 14 | 8 | | | | 18 | 5 | | | | 21 | 12½ | | | | 25 | 9 | 46 48 | Sun's upper limb | | 29 | 2½ | | Ditto lower limb | | 33 | 10½ | | | | 2 | 4 53½ | 41 23 | Sun's upper limb | | 9 | 25 | | Ditto lower limb | | 13 | 56 | | | | 18 | 4½ | | | Cloudy with rain at night. | 2—2 | h ' " | h ' " | | |---|---|---|---| | 23 | 28 24 | 9 35 41 | Sun's upper limb | | 31 | 58½ | 32 6½ | | | 35 | 30 | 28 35 | | | 23 | 39 11 | | Sun's lower limb | | 23 | 55 11 | 9 8 53 | Sun's upper limb | | 58 | 45+ | 5 17 | | | 0 | 2 16½ | 1 46 | | | 0 | 6 0 | 8 58 7½ | Sun's lower limb | | 0 | 16 40 | 8 47 22½ | Sun's upper limb | | 20 | 15 | 43 45+ | | | 23 | 50 | | | | 27 | 33½ | | Sun's lower limb | | 38 | 38½ | | | | 42 | 19 | 8 21 39 | Sun's upper limb | | Clouds | 8 18 5½ | | | | 49 | 44 | | Sun's lower limb | 4 31 53½ ### Equal Altitudes of the Sun and Stars | Date | Time per Clock of the equal Altitudes of the O's limb, and of *'s. | Zen. distance of points on the limb of the quadrant, the nonius was set at. | O's limb, and Stars observed. | Time per Clock when the O's cent. and * passed the merid. from the mean of the Observations. | |------------|------------------------------------------------------------------|---------------------------------------------------------------------------------|-------------------------------|------------------------------------------------------------------------------------------------| | **1769 June** | **2** | **Cloudy** | | | | | **1 o o** | **8 1 58½** | **49 45** | **O's upper limb** | | | **1st wire clou.** | **7 58 11** | | | | | **1 5 48½** | **9 31 5 54 27** | | | | | **13 28** | | | | | | **Clo. 1st wire** | | | | | | **1 26 30** | **30 25 ::** | **47 00** | **O's upper limb** | | | **1 56 28** | | | | | | **Clouds** | **Cloudy at the times corresponding to these** | **42 43** | **O's upper limb** | | | **2 17 56½** | | | | | | **22 37** | | | | | | **27 18** | | | | | | **32 17½** | | | | | | **12 54 30 ::** | **The O's last limb set.** | | | | | **Cloudy all night.** | | | | | | **20 25** | **Cloudy with rain.** | | | | **3** | **0 16 47** | **8 54 43** | **56 30** | **O's upper limb** | | | **20 23** | **Clouds** | | | | | **23 57 :** | **8 47 35 ::** | | | | | **Then cloudy** | | | | | | **0 31 27½** | **Clouds** | **54 25** | **O's upper limb** | | | **35 6** | **Clouds** | | | | | **38 40½** | **8 32 51 :** | | | | | **42 27** | **Clouds** | **O's lower limb** | | | | **0 46 50½** | **Clouds** | **52 16** | **O's upper limb** | | | **Clouds** | **Clouds** | | | | | **54 10** | **8 17 18½** | | | ### Equal Altitudes of the Sun and Stars. | Time per Clock of the equal Altitudes of the Sun's limb, and of *'s. | Zen. distance of points on the limb of the quadrant. The monius was set at. | Stars observed. | Time per Clock when the Sun's center passed the merid. from the mean of the Observations. | |---|---|---|---| | **1769 June** | | | | | h | m | s | | | | | | 3 | 54 | 19 | Clouds | O's low. middle wire | 4 | 35 | 37.8 | | | 57 | 58½ | Clouds | Ditto last wire | | | | | 4 | 43 | | | | | | | 8 | 28 | | | | | | | 12 | 11½ | | | | | | | 16 | 5+ | | | | | | | 22 | 2 | Clouds | | | | | | | | Clouds | | | | | | | | Clouds | 7 | 41 | 43 | | | 33 | 47 | 7 | 37 | 40 | O's low. limb | | | | | | | | | | | | | Clouds | So hazy that I could not see the Sun's limb at time correspond. | | | | | | | Clouds | | | | | | 50 | 46 | | | | | | | 55 | 00 | 7 | 16 | 25 | O's low. limb | | | 2 | 0 | 2 | Clouds | | | | | | | Clouds | 7 | 7 | 9 | | | | | Clouds | 7 | 2 | 54½ | | | 3 | 1 | 00 | Clouds | | | | | | 6 | 55 | 6 | 4 | 25 | | | | 13 | 4 | Clouds | | | | | Then cloudy | | | | | | | Though the air at external contact was not quite so clear as at some times I have seen, yet the sun's limb appeared well defined, and the spots in the disk very strong, their edges keen and distinct. At the internal contact, the air was much changed, and the limb of Venus seemed to cohere to the Sun's limb, by a protuberance that appeared like a dark shade; which seemed to prevent my seeing the thread of light for about 40" longer than I expected. ### Equal Altitudes of the Sun and Stars. When the planet was upon the ⊙’s disk, there appeared a faint light shade (having a gentle fluctuating motion) round its periphery, and widest on that part farthest on the Sun’s disk: it appeared as per fig. the black circle representing the periphery of Venus, and the dotted one that of the shade, which was very regular and well defined; \( v \) the upper, and \( m \) the lower part of the planet: and the whole shade was apparently of equal brightness. | Time per Clock | Zen. distance of points of the limb of the quadrant. the nonius was set at. | ⊙’s limb, and Stars observed. | Time per Clock when the ⊙’s cent.and passed the merid. from the mean of the Observations. | |----------------|-------------------------------------------------|--------------------------------|-------------------------------------------------| | 14 45 2½ | | 38 17 α Lyrae | | | 48 38 | | | | | 52 13 | | | | | 15 11 39+ | | 34 28 Ditto | | | 15 16½ | | | | | 18 48+ | | | | | 22 15 | Cloudy with rain | | | | 40 | Cloudy | | | | 49 28 | The eclipse of the sun began | | | | 49 35 | Very plain | | | | 52 | Cloudy with rain | | | | 23 28 | The clouds began to break; and from this time to 23h 54’ I endeavoured with a micrometer (of Mr. Dollond’s construction) to get measurements for determining the digits eclipsed; but was so interrupted by flying clouds, that nothing could be done with certainty; then cloudy with rain till the end of the eclipse was past. | ⊙—Cloudy ⊙—Cloudy ⊙—Cloudy ### Equal Altitudes of the Sun and Stars | Date | Time per Clock of the equal Altitudes of the Sun's limb, and of *'s. | Zen. distance of points of the limb of the quadrant, the nonius was set at. | Stars observed. | Time per Clock when the Sun's cent. and * passed the merid. from the mean of the Observations. | |------------|---------------------------------------------------------------------|------------------------------------------------------------------------------|-----------------|----------------------------------------------------------------------------------| | 1769 June | | | | | | D — 5 | 15 10 56 | | | | | | 14 31½ | | | | | | 18 5 | | | | | | | | | 34 28 α Lyrae | | § — 7 | 14 43 32½ | | | | | | 47 6 | | | | | | 50 36 | | | | | | | | | 38 17 α Lyrae | | ⊙ — 11 | 14 42 4 | | | | | | 45 37+ | | | | | | 49 8 | | | | | | | | | 38 17 α Lyrae | | h — 15 | Wound up the clock | | | | | § — 21 | 14 41 54 | | | | | | 45 25 | | | | | | | | | 38 17 α Lyrae | | ⊙ — 25 | 16 25 45 | | | | | | 29 59 | | | | | | 34 15 | | | | | | | Cloudy at the time corresponding to these | | | | | | | | 23 22 α Lyrae | | § — 30 | 2 30 23 | Clouds | | | | | 34 5 | Clouds | | | | | 37 43½ | 9 57 7 :: | | | | | 41 31 | | | | | | 2 45 29 | 9 49 24 | | | | | 49 14 | 9 45 38 | | | | | Clouds | Clouds | | | | | | | | 49 18 ⊙'s upp. limb | | | | | | ⊙'s low. limb | | | 14 49 35½ | ⊙'s last limb set | | | | | | | | 6 17 28,9 | | | 16 14 3 | Cloudy at the time corresponding | | | | | 18 5 | | | 25 6 α Lyrae | | | 16 23 53 | | | | | | 28 8 | | | 23 22 Ditto | | | 32 24 | | | | ### Equal Altitudes of the Sun and Stars | Year | Month | Time per Clock of the equal Altitudes of the Sun's limb, and of *'s. | Zen. distance or points of the limbs of the quadrant, the monius was set at. | Stars observed. | Time per Clock when the Sun's cent. and *'s passed the merid., from the mean of the Observations. | |------|-------|---------------------------------------------------------------|-----------------------------------------------------------------|----------------|--------------------------------------------------| | 1769 | July | 5 — 1 | 3 25 22½ | 9 17 1 | 44 33 | Sun's upper limb | | | | | 3 29 22 | 13 0 | | | | | | | Clouds | | | | | | | 30 40 17 | Clouds | 8 57 51 | 42 40 | Ditto | | | | | Clouds | | | | | | | 48 37 | | | | | | | | 16 9 39½ | | | 25 6 | α Lyrae | | | | Clouds | | | | | | | | Clouds | | | | | | 2 — 3 | | 16 8 53 | | | 25 6 | α Lyrae | | | | 12 54½ | | | | | | | | 16 55 | | | | | | | | 22 45— | | | | | | | | 27 0— | | | | | | | | 31 14½ | | | 23 22 | Ditto | | 4 — 6 | | 2 12 20 | | | | | | | | 15 56 | | | | | | | | 19 29 | | | | | | | | 23 10+ | | | | | | | | 10 50 31½ | | | | | | | | 26 51 | | | | | | | | 30 29½ | | | | | | | | 34 3½ | | | | | | | | 37 46 | | | | | | | | 41 55½ | | | | | | | | 11 7 21+ | | | 57 30 | Sun's upper limb | | | | 3 44½ | | | | | | | | 0 13+ | | | | | | | | 10 52 49 | | | | | | | | 49 13 | | | | | | | | 45 39+ | | | | | | | | 55 26 | | | | | | | | Sun's upper limb | | | 6 39 56,8 | | | | Sun's lower limb | | | | | | 8 — 7 | | 16 11 24 | | | 25 6 | α Lyrae | | | | 15 24 | | | | | | | | 16 21 15— | | | | | | | | 25 29 | | | | | | | | 29 45 | | | | | | | | 23 22 | | | | | | | | Ditto | | | | | Vol. LX. | Date | Time per Clock of the equal Altitudes of the Sun's limb, and of *'s. | Zen. distance or points on the limb of the quadrant, the nonius was set at. | Stars observed. | Time per Clock when the Sun's cent. and *'s passed the merid. from the mean of the Observations. | |------|---------------------------------------------------------------|-----------------------------------------------------------------|----------------|----------------------------------------------------------------------------------| | 1769 July | Wound up the Clock | | | | | 16 | 4 44 15 | Clouds | 43 45 | Sun's upper limb | | | 48 34 | 9 52 17 | | | | | 52 54 | 47 59 | | | | | 57 27½ | 43 24½ | | | | | 5 1 56 | 9 38 55 | 41 12 | Sun's upper limb | | | 6 32 | 34 14 | | | | | 5 16 8 | 9 24 42 | | | | 21 | 16 2 4 | | 25 6 | α Lyrae | | | 6 6 | | | | | | 10 6½ | | | | | | 16 15 56½ | | 23 22 | Ditto | | | 20 11 | | | | | | 24 26½ | | | | | 22 | 3 41 45½ | 11 35 12+ | 55 6 | Sun's upper limb | | | 45 27 | 31 32 | | | | | 49 4 | 27 53 | | | | | 49 15 | 27 42 | | | | | 52 54½ | 11 24 4 | | | | | 3 56 48½ | 11 20 9½ | 53 1 | Sun's upper limb | | | 4 0 35 | 16 25 | | | | | Clouds | 12 42 | | | | | 4 16 47½ | 11 0 11½ | 50 50 | Sun's upper limb | | | 4 20 47 | 10 56 23½ | | | | | 24 37+ | 10 52 23 | | | | | 16 1 42½ | | 25 6 | α Lyrae | | | 5 43½ | | | | | | 9 44 | | | | ### Equal Altitudes of the Sun and Stars | Date | Time per Clock of the equal Altitudes of the O's limb, and of *'s. | Zen. distance or points on the limb of the quadrant. The nonius was set at. | O's limb, and Stars observed. | Time per Clock when the O's cent. and *'s passed the merid. from the mean of the Observations. | |------------|------------------------------------------------------------------|-----------------------------------------------------------------|-----------------------------|--------------------------------------------------------------------------------| | July 1769 | h ' " | | | | | 12 - 22 | 16 15 33½ | | | | | | 19 49 | | | | | | 24 4 | | | | | 6 - 25 | 16 0 33 | | | | | | 4 35½ | | | | | | 8 35½ | | | | | | 14 25 | | | | | | 18 40 | | | | | | 22 25 | | | | | 12 - 29 | 15 59 4 | | | | | | 16 3 3½ | | | | | | 7 5 | | | | | | Then cloudy | | | | | August | | | | | | O - 6 | 4 2 35+ | | | | | | 6 13½ | | | | | | 9 46+ | | | | | | 9 57 | | | | | | 13 33 | | | | | | 12 49 1 | | | | | | 4 18 36 | | | | | | 22 17 | | | | | | 25 54 | | | | | | 29 42+ | | | | | | 12 43 58+ | | | | | | Clouds | | | | | | 12 36 42 | | | | | | 29 42+ | | | | | | 12 32 53 | | | | | 7 | Clouds | | | | | | Clouds | | | | | | 16 17 59 | | | | | 8 - 9 | | | | | | | 16 17 15+ | | | | | | | | | | O o o 2 ### Equal Altitudes of the Sun and Stars | Date | Time per Clock of the equal Altitudes of the Sun's Limb, and of *'s. | Zen. distance or points on the limb of the quadrant, the horizon was set at. | Stars observed | Time per Clock when the Sun's cent, and *'s passed the meridian, from the mean of the Observations | |------------|---------------------------------------------------------------------|---------------------------------------------------------------------------------|----------------|--------------------------------------------------------------------------------------------------| | 1769 April | | | | | | 8—9 | h ' " | h ' " | | | | | 17 25 24½ | 25 45 α Cygni | | | | | 29 00 | | | | | | 32 32 | | | | | | 37 43½ | | | | | | 41 21 | | | | | | 44 56 | | | | | 8—16 | h ' " | h ' " | | | | | 17 22 49 | 25 45 α Cygni | | | | | 26 25 | | | | | | 29 57 | | | | | | 17 35 7½ | 24 oo Ditto | | | | | 38 44½ | | | | | | 42 20+ | | | | | b—17 | h ' " | h ' " | | | | | 17 51 17 | 21 57 23 | | | | | 54 58½ | | | | | | 58 38 | | | | | | 18 4 23 | 19 53 Ditto | | | | | 8 9½ | | | | | | 11 55 | | | | | d—21 | h ' " | h ' " | | | | | 17 49 47 | 21 41 α Cygni | | | | | 53 28 | | | | | | 57 8 | | | | | | 18 2 52 | 19 53 Ditto | | | | | 6 39 | | | | | | 10 24 | | | | | 24—24 | h ' " | h ' " | | | | | 17 10 47½ | 25 45 α Cygni | | | | | 23 22½ | | | | | | 26 25 | | | | | | Clouds | | | | | | 18 5 30 | 19 53 Ditto | | | | | 9 17½ | | | | ### Equal Altitudes of the Sun and Stars | Date | Time per Clock of the equal Altitudes of the ⊙'s limb, and of ✡'s. | Zen. distance or points on the limb of the quadrant, the nonius was set at. | ⊙'s limb, and Stars observed. | Time per Clock when the ⊙'s cent, and ✡'s passed the merid. from the mean of the Observations. | |------------|------------------------------------------------------------------|----------------------------------------------------------------------------|-------------------------------|---------------------------------------------------------------------------------| | 1769 August | | | | | | ⊙—27 | h ' " | o ' " | | | | | Clouds | | | | | | 17 22 15½ | | | | | | Clouds | | | | | | 17 34 36 | | | | | | 38 11 | | | | | | 23 30 | | | | | | Saw a Comet near | | | | | Sept. | | | | | | ♡—1 | | | | | | | Saw the aforementioned Comet through a thick haze; it was moved to the eastward. | | | | | 24—7 | | | | | | | Clouds | | | | | | 17 21 40 | | | | | | 17 26 52 | | | | | | Clouds | | | | | | 34 2½ | | | | | | Rain in the night | | | | | | 24 00 | | | | | ⊙—10 | | | | | | | Cloudy with rain till about half past 4 in the morning, when the clouds broke in the east, and I saw the Comet a little to the south of Procyon; its tail extended nearly to the belt of Orion, and made a splendid appearance. Cloudy and rain in 8' after. | | | | | D—11 | | | | | | ♡—15 | | | | | | | 17 23 53+ | 22 3 3+ | | | | | 27 32 | 21 59 26 | | | | | 31 6 | 21 55 50½ | | | | | | | | | | | 17 40 25:: | | | | | | 44 8 | 21 42 50 | | | | | Clouds | | | | | | | | | | | | 19 54 59½ | 21 31 58+ | | | | | 58 46 | 21 28 10+ | | | | | 2 32 | | | | --- *Note:* The observations are recorded in detail, including times, conditions, and celestial objects observed. ### Equal Altitudes of the Sun and Stars | Time per Clock of the equal Altitudes of the ⊙'s limb, and of *'s. | Zen. distance or points on the limb of the quadrant, the nonius was set at. | ⊙'s limb, and Stars observed. | Time per Clock when the ⊙'s cent. and *'s passed the merid. from the mean of the Observations. | |---|---|---|---| | **1769 Sept.** | | | | | 2 — 18 | h m s | h m s | ⊙'s limb, and Stars observed. | | | 17 22 46 | 24 00α Cygni | | | | 26 24+ | | | | | 29 59 | | | | | 3 — 20 | h m s | h m s | ⊙'s limb, and Stars observed. | | | 17 53 5½ | 19 41α Cygni | | | | 56 53½ | | | | | 18 0 39 | | | | | Clouds | 18 00 Ditto | | | | 18 9 37½ | | | | | Clouds | | | | | 24 — 21 | h m s | h m s | ⊙'s limb, and Stars observed. | | | 8 10 33 | 13 54 51 | 63 48 ⊙'s upp. limb | | | 15 20½ | 50 4½ | | | | 20 9 | 45 16 | | | | 20 26 | 44 59— | ⊙'s low. limb | | | 25 21 | 40 6½ | Ditto | | | 8 32 44½ | 13 32 36 | 61 30 ⊙'s upp. limb | | | 38 8 | | | | | 43 27 | | | | | 43 46 | | ⊙'s low. limb | | | 49 15 | | | | | 17 52 43 | | | | | 56 33½ | | | | | 18 0 17½ | | | | | 18 5 20½ | | | | | 9 15½ | | | | | 13 10 | | | | | 8 — 29 | h m s | h m s | ⊙'s limb, and Stars observed. | | | 9 9 9 | 13 47 59 | 63 24 ⊙'s upp. limb | | | 14 54 | | | | | 20 45 | | | | | Clouds | Very thick and hazy | | | | Clouds | | | | | Cloudy at the time corresponding to these | 18 00α Cygni | | | --- *Note:* The table provides data on the equal altitudes of the Sun and Stars, including times per clock, zenith distances, and observations made during specific dates in September 1769. ### Equal Altitudes of the Sun and Stars | Time per Clock of the equal Altitudes of the ⊙'s limb, and of ✡'s. | Zen. distance or points on the limb of the quadrant, the nonius was set at. | ⊙'s limb, and Stars observed. | Time per Clock when the ⊙'s cent. and ✡'s passed the merid. from the mean of the Observations. | |---|---|---|---| | **1769 Sept.** | | | | | h ' " | h ' " | o ' " | | | 8 — 25 | 8 15 24 | 19 28 | Cloudy at the time corresponding to these | 16 50 Ditto | | 18 26 14½ | 30 39 | 35 3½ | | 15 CO. | | 18 53 8 | 57 52 | 19 4 1 | | | | 8 40 12 | 14 23 27½ | 45 10 | 18 34 | 66 55 ⊙'s upp. limb | | 50 5 | 13 37 | 50 24 | 14 13 17½ | ⊙'s low. limb | | 55 27 | 8 16 | | Ditto | | 9 3 34 | 14 0 8 | 9 3 | 13 54 40 | 64 35 ⊙'s upp. limb | | 14 32 | 49 4 | | | 11 32 14¾ | | 9 9 18 | 13 54 25 | 14 55 | 13 48 43 | Ditto low. limb | | 20 41 | 43 2 | | | | | 18 19 7 | 20 56 39 | 16 50 α Cygni | | 18 25 52½ | 20 49 53+ | 30 14 | 45 30 | 15 00 Ditto | | 34 41 | 41 5 | | | 19 37 52¾ | | **9 Oct.** | | | | | 9 18 33 | 14 11 15½ | 24 12 | 13 59 58 | 65 50 ⊙'s upp. limb | | 29 53 | | | | | | 24 29 | 59 32 | 30 16 | | ⊙'s low. limb. | | 36 7 | 53 37 | | | 11 45 17¾ | ### Equal Altitudes of the Sun and Stars | Date | Time per Clock of the equal Altitudes of the Sun's Limbs, and of *'s. | Zen. distance or points on the limb of the quadrant, the nonius was set at. | Stars observed | Time per Clock when the Sun's cent. and *'s palled the merid. from the mean of the Observations. | |------------|---------------------------------------------------------------------|-----------------------------------------------------------------------------|----------------|----------------------------------------------------------------------------------| | 1769 October 8 - 4 | 9 44 35 13 45 15 | 63 36 Sun's upper limb | | | | 24 - 5 | 18 24 1 20 48 2 28 24 43 39 32 49 39 12 | {15 00 Cygni} | | 19 36 1,3 | | | 18 49 52 20 22 10½ 55 39 20 16 25 | {12 14 Ditto} | | | | 8 - 10 | 9 44 48 14 24 28: 50 48 14 18 30 56 50 Clouds | {67 23 Sun's upper limb} | | 12 5 1,6 | | | 9 51 5 57 16 | {Sun's lower limb} | | | | | 10 3 33 14 5 42 | | | | | 24 - 12 | 9 20 33 15 2 3 25 40 14 56 53 30 49 51 47 | {71 00 Sun's upper limb} | | 12 11 41,0 | | | 25 55 14 56 36 31 10 51 25 36 26 46 8 | {Ditto lower limb} | | | | 23 - 23 | 9 23 7 27 46 32 25 | {Cloudy at the time corresponding} | {68 16 Sun's upper limb} | | | | 9 28 11 32 45 37 26½ 15 59 39½ | | | | | | 9 45 16 15 51 45 50 18 46 40 55 20 41 37½ | {75 54 Sun's upper limb} | | 12 48 52,1 | | | 9 50 35 46 24 55 42 41 16 10 0 50 36 9 | {Ditto lower limb} | | | Apparent Zenith Distances of the ☉, ♦, and *'s. | Date | ☉, ♦, or *'s observed | Apparent zenith distance on the meridian | Barom. | Ther. | |--------|-----------------------|------------------------------------------|--------|-------| | April 1769 | Spica | 64° 45' 24" | | | | | ♦'s upper limb | 42° 51' 00" | 29 | 69 | | | Ditto lower limb | 43° 22' 40" | | | | | Spica | 64° 45' 32" | | | | | Arcturus | 34° 26' 20" | | | | | ♦'s center | 71° 21' 36" | | | | | ♦'s lower limb | 77° 30' 36" | | | | | Antares | 80° 38' 40" | 29 | 52 | | | Spica | 64° 45' 16" | 20 | 93 | | | Arcturus | 34° 27' 00" | | | | | Ditto | 34° 27' 00" | | | | May | ♦'s upper limb | 39° 37' 40" | 29 | 97 | | | Ditto lower limb | 40° 9' 16" | | | | | Spica | 64° 46' 00" | | | | | ♦'s upper limb | 39° 19' 24" | | | | | Ditto lower limb | 39° 51' 16" | | | | | ♦'s lower limb | 39° 33' 26" | | | | | Spica | 64° 46' 00" | | | | | Arcturus | 34° 26' 52" | | | | | Antares | 80° 39' 12" | | | | | ♦'s upper limb | 38° 26' 16" | | | | | Spica | 64° 45' 50" | | | | | Arcturus | 34° 26' 52" | | | | | ♦'s upper limb | 37° 36' 00" | | | | | Ditto lower limb | 38° 7' 56" | | | | | Spica | 64° 45' 50" | | | | | Arcturus | 34° 26' 48" | | | | | Jupiter's center | 70° 52' 24" | | | Vol. LXX. P p p Apparent Zenith Distances of the ⊙, ♦, and ✡'s. | ⊙, ♦, or ✡'s observed | Apparent zenith distance on the meridian | Barom. | Ther. | |-----------------------|----------------------------------------|--------|------| | May | | | | | 12 | Spica | 64 45 46 | | | | Arcturus | 34 26 48 | 29 86 | 43 | | | ♦'s upper limb | 36 17 16 | 29 60 | 54 | | | Ditto lower limb | 36 49 48 | | | | | Spica | 64 46 00 | | | | 13 | ♦'s upper limb | 36 2 42 | 29 52 | 58 | | | Ditto lower limb | 36 34 30 | | | | | ♦'s upper limb | 35 48 28 | | | | | Ditto lower limb | 36 20 2 | 29 55 | 57 | | | ♦'s upper limb | 55 50 56 | 29 63 | 49 | | | Spica | 64 45 55 | | | | | Arcturus | 34 26 52 | 29 69 | 44 | | 15 | ♦'s upper limb | 60 54 40 | 29 69 | 44 | | | Spica | 64 46 00 | | | | 18 | ♦'s upper limb | 34 53 40 | | | | | Ditto lower limb | 35 25 12 | 29 54 | 51 | | | Spica | 64 46 00 | | | | | ♦'s upper limb | 73 30 32 | | | | | ♦'s cent. | 70 30 20 | 29 64 | 37 | | 23 | ♦'s upper limb | 33 53 00 | 29 22 | 59 | | | Ditto lower limb | 34 24 32 | | | | | Arcturus | 34 26 52 | 29 34 | 55 | | 24 | ♦'s upper limb | 33 41 48 | 29 41 | 64 | | | Ditto lower limb | 34 13 38 | | | | June | | | | | 11 | ♦'s upper limb | 31 25 40 | 29 41 | 53½ | | | Ditto | 31 22 00 | 29 66 | 55 | | | Arcturus | 34 26 44 | | | | 14 | ♦'s upper limb | 72 27 14 | 29 36 | 55 | | | ♦'s upper limb | 31 13 00 | 29 46 | 58 | | 17 | Antares | 80 39 12 | | | | | ♦'s upper limb | 78 44 48 | 29 35 | 47 | | 18 | ♦'s upper limb | 31 7 54 | 29 41 | 54 | | | Ditto lower limb | 31 39 42 | | | In observing the ⊙'s zen. dist. I set the ⊙'s limb just (or scarcely) to touch the wire; which is the reason why the ⊙'s diameter is in this observation so much greater than made before. Observed without the dark glass; it being a very thick fog. Apparent Zenith Distances of the ⊙, ♈, and *'s. | Year | Month | Day | ⊙’s upper limb | Ditto lower limb | ⊙’s upper limb | Ditto lower limb | ⊙’s upper limb | Ditto lower limb | |------|-------|-----|----------------|------------------|----------------|------------------|----------------|------------------| | 1769 | June | 23 | 31° 7' 20" | 31° 39' 12" | 31° 12' 6" | 31° 43' 56" | 31° 24' 6" | 29° 71' | | | | 26 | | | | | | | | | | 30 | | | | | | | | | July | 1 | 31° 28' 00" | 31° 48' 00" | 32° 19' 56" | 30° 39' 20" | | | | | | 5 | | | | | | | | | | 6 | | | | | | | | | | 9 | 32° 14' 46" | 76° 58' 16" | 32° 56' 12" | 78° 27' 10" | | | | | | 13 | | | | | | | | | | 14 | | | | | | | | | | 17 | 33° 25' 28" | 33° 57' 26" | | | | | | | | 22 | | | | | | | | | August| 2 | 36° 54' 30" | 46° 33' 12" | 61° 39' 20" | 41° 56' 20" | 42° 27' 56" | | | | | 17 | | | | | | | | | | 19 | | | | | | | Apparent zenith distance on the meridian. Barom. Ther. | | | 29° 17' 60" | 29° 38' 5" | 29° 71' 60" | 29° 62' 62" | 29° 72' 67" | 29° 75' 57" | 29° 57' 63" | 29° 34' 57" | 29° 49' 59" | 29° 66' 56" | 29° 12' 59" | 29° 49' 63" | 29° 50' 62" | 29° 69' 54" | 29° 70' 51" | 29° 40' 57" | To find the Error of the Line of Collimation of the Quadrant. I set up a board at the distance of about 300 yards, painted black, with two white marks on it; the diameter of each white mark = 3\(\frac{1}{2}\) inches, and the distance of their centers \(= 1\frac{1}{2}\) inches = the difference of the height of the center of the telescope, when the quadrant is inverted, and made the following observations. | Zen. dist. of the upper mark. | Zen. dist. of the lower mark. | |-----------------------------|-------------------------------| | 89° 50' 0" | | | 50° 6" | | | 4° 6" | | | 0° | | | 4° | | | 0° | | | Mean = 89° 50' 3" | | The quadrant in its proper position. | Zen. dist. of the lower mark. | |-------------------------------| | 90° 7' 20" | | 7' 20" | | 18" | | 14" | | 16" | | 20" | | 20" | | Mean = 90° 7' 18\(\frac{3}{4}\)" | | 89° 50' 3" | | 179° 57' 21\(\frac{3}{4}\)" | | 180° 0' 0" | | 2° 38' 7" | | 1° 19' 3" | To be added to the observed zenith distance. I took the telescope off the quadrant, and adjusted the line of collimation something nearer. I found the error of the line of collimation of the quadrant in the same manner, as on the 22d, thus: | Zen. dist. of the upper mark. | Zen. dist. of the lower mark. | |-------------------------------|-------------------------------| | 89° 51' 0" | | | 51° 0" | | | 51° 0" | | | 51° 0" | | | 50° 56" | | | 51° 4" | | | 51° 6" | | | 51° 6" | | | Mean = 89° 51' 2" | | Quadrant in its proper position. | Zen. dist. of the lower mark. | |-------------------------------| | 90° 7' 20" | | 7' 12" | | 24" | | 20" | | 22" | | 20" | | 18" | | 16" | | 18" | | 20" | | 12" | | Mean = 90° 7' 18\(\frac{3}{4}\)" | | 89° 51' 2" | | 179° 58' 20\(\frac{1}{4}\)" | | 180° 0' 0" | | 2° 39' 9" | | 0° 50" | N.B. This method is given us by the Rev. Mr. Nevil Maskelyne, Astronomer Royal, in his description of Mr. Bird's astronomical quadrant, published with his instructions for the observation of the late Transit of Venus, at the end of the Nautical Almanac of 1769, see p. 23, and may be followed with great accuracy; and to avoid the error that may fall on any two divisions of the quadrant, as many different divisions may be taken as the observer pleases, by shifting the board that has the marks on it, higher or lower. For the Latitude of the Observatory at Cavan. | Year | Month | Day | App. zenith distances on the merid. | Refra. | O's px. in alt. | *'s ab. in decl. | *'s nut. in decl. | Error of the coll. line of the quad. | True zenith distances | O or *'s true decl. at the time of observation | Latitude from each observation | |------|-------|-----|-----------------------------------|--------|----------------|-----------------|-----------------|----------------------------------|----------------------|-----------------------------------------------|--------------------------------| | 1769 | April | 10 | Spica | 64 45 24 | 2 0,5 | -7,6 | -6,3 | + | 64 48 29,6 | 9 57 00,9 | 54 51 30 | | | | 20 | O's center | 43 6 50 | 53,1 | | | | 43 8 66,3 | 11 42 55,2 | 51 51 | | | | 22 | Spica | 64 45 32 | 2 2,4 | -7,5 | -6,2 | 1,19+ | 64 48 39,7 | 9 57 00,5 | 51 39 | | | | 22 | Arcturus | 34 26 20 | 39,7 | -5,9 | -5,8 | | 34 28 7,0 | 20 23 33,8 | 51 41 | | | | | Antares | 30 38 40 | 41,0 | -2,0 | -2,7 | | 80 45 35,3 | 25 53 56,7 | 51 39 | | | | 25 | Spica | 64 45 16 | 3,0 | -7,5 | -6,2 | | 64 48 24,3 | 9 57 0,6 | 51 24,3 | | | | 26 | Spica | 64 46 6 | 0,8 | -7,5 | -6,2 | + | 64 43 43,1 | 9 57 0,7 | 51 42 | | | | | Arcturus | 34 27 | 39,1 | -5,3 | -5,8 | | 34 28 18,0 | 20 23 33,6 | 51 52 | | | | 28 | Ditto | 34 27 | 39,4 | -4,8 | -5,8 | 50 | 34 28 26,8 | 20 23 33,5 | 52 00,0 | | | | 29 | Ditto | 34 27 | 39,4 | -4,8 | -5,8 | | 34 28 18,8 | 20 23 33,5 | 51 52 | | | | 30 | O's center | 39 53 28 | 47,2 | 5,4 | | | 39 54 59,8 | 14 56 48,5 | 51 48 | | | | | Spica | 64 46 00 | 0,5 | -7,4 | -6,2 | | 64 48 46,9 | 9 57 00,8 | 51 46 | | | May | 1 | O's center | 39 35 20 | 47,9 | 5,4 | | | 39 36 52,5 | 15 14 57,2 | 51 50 | | | | 2 | O's L. L. | 39 33 26 | 47,7 | 5,4 | | | 39 34 58,3 | 15 52 50,9 | 51 55 | | | | 3 | Spica | 64 46 00 | 0,7 | -7,2 | -6,2 | | 64 48 37,3 | 9 57 1,0 | 51 36 | | | | | Arcturus | 34 26 52 | 39,0 | -3,8 | -5,7 | | 34 28 11,5 | 20 23 33,4 | 51 45 | | | | | Antares | 30 39 12 | 36,0 | -2,6 | -2,6 | | 80 45 32,8 | 25 53 57,0 | 51 36 | | | | 6 | Spica | 64 45 50 | 3,1 | -7,0 | -6,2 | | 64 48 29,9 | 9 57 1,2 | 51 29 | | | | | Arcturus | 34 26 52 | 39,9 | -3,2 | -5,7 | | 34 28 13,0 | 20 23 33,2 | 51 43 | | | | 7 | O's center | 37 51 58 | 43,5 | 5,2 | | | 37 53 26,3 | 16 58 21,2 | 51 43 | | | | | Spica | 64 45 50 | 2 2,4 | -7,0 | -6,1 | | 64 48 29,3 | 9 57 1,3 | 51 28 | | | | | Arcturus | 34 26 48 | 39,7 | -3,0 | -5,7 | | 34 28 9,0 | 20 23 33,1 | 51 42 | | | | 10 | Spica | 64 45 46 | 3,5 | -6,9 | -6,1 | | 64 48 26,5 | 9 57 1,5 | 51 25 | | | | | Arcturus | 34 26 48 | 40,0 | -2,3 | -5,7 | | 34 28 10,0 | 20 23 32,9 | 51 43 | | | | 12 | O's center | 30 33 32 | 41,6 | 5,8 | | | 36 34 58,5 | 18 16 48,4 | 51 47 | | | | | O's center | 36 18 36 | 48,0 | 5,0 | | | 36 20 1,8 | 18 31 36,0 | 51 38 | | | | 14 | O's center | 36 4 15 | 40,2 | 5,0 | | | 35 5 40,2 | 18 46 4,5 | 51 45 | | | | | Spica | 64 45 55 | 2 2,5 | -6,5 | -6,1 | | 64 48 34,9 | 9 57 1,7 | 51 33 | | | | | Arcturus | 34 26 52 | 39,6 | -1,5 | -5,7 | | 34 28 14,4 | 20 23 32,7 | 51 47 | | | | 18 | O's center | 35 9 26 | 39,8 | 4,9 | | | 35 10 50,9 | 19 40 46,0 | 51 37 | | | | | Spica | 64 46 00 | 4,4 | -6,1 | -6,1 | | 64 48 42,2 | 9 57 2,0 | 51 40 | | | | 23 | O's center | 34 8 46 | 36,9 | 4,8 | | | 34 10 8,1 | 20 41 36,8 | 51 45 | | | | | Arcturus | 34 26 52 | 38,2 | +0,2 | -5,6 | | 34 28 14,8 | 20 23 32,2 | 51 47 | | | | 24 | O's center | 33 57 43 | 36,5 | 4,7 | | | 33 59 4,8 | 20 52 44,3 | 51 49 | | | June | 11 | O's U. L. | 31 25 40 | 34,0 | 4,4 | | | 31 26 59,6 | 23 8 38,7 | 51 28 | | | | | O's U. L. | 31 13 00 | 33,4 | 4,4 | | | 31 14 19,0 | 23 21 23,6 | 51 30 | For the Latitude of the Observatory at Cavan. | Date | Star | Ap. zenith distances on the merid. | Refra. | O's px. in alt. | *'s ab. hor. = 8°5 | *'s nut. decl. | Error of the line of coll. of the quad. | True zenith distances | O or *'s true decl. at the time of observation | Latitude from each observation | |------|--------------|------------------------------------|--------|-----------------|-------------------|----------------|------------------------------------------|-----------------------|--------------------------------------------------|--------------------------------| | 1769 | June | | | | | | | | | | | | Antares | 8° 39' 12" | 5° 34' 8" | | | | | | | | | | O's center | 3° 23' 48" | 3° 33' 9" | 4° 4 | | | | | | | | | O's center | 3° 23' 16" | 3° 33' 2" | 4° 4 | | | | | | | | | O's center | 3° 28' 10" | 3° 33' 6" | 4° 4 | | | | | | | | | O's U. L. | 3° 24' 6" | 3° 33' 8" | 4° 4 | | | | | | | | July | | | | | | | | | | | | | O's U. L. | 3° 28' | 3° 33' 5" | 4° 4 | | | | | | | | | O's center | 3° 3' 58" | 3° 33' 7" | 4° 5 | | | | | | | | | Antares | 3° 39' 20" | 3° 31' 1" | | | | | | | | | | O's U. L. | 3° 14' 46" | 3° 34' 3" | 4° 5 | | | | | | | | | O's U. L. | 3° 56' 12" | 3° 36' 0" | 4° 6 | | | | | | | | August | | | | | | | | | | | | | O's center | 3° 41' 27" | 3° 36' 2" | 4° 7 | | | | | | | | | O's L. L. | 3° 53' 24" | 3° 38' 4" | 4° 8 | | | | | | | | | O's U. L. | 3° 54' 30" | 4° 1' 4" | 5° 1 | | | | | | | | | α Aquilae | 4° 33' 12" | 5° 9' 5" | | | | | | | | Mean of the whole 5° 40' 8" N. B. By comparing Mr. Flamstead's observations with those made by the Rev. Mr. Maskelyne, Astronomer Royal, in the years 1765 and 1766, Arcturus moves annually 2°0144 Southward in declination; therefore 18°6 is subtracted in the above from the declination of Arcturus, as settled from Dr. Bradley's observations for the beginning of the year 1760. The following are the difference of R. A. between the D's limb and *'s, observed by wires placed in the focus of the eye glass of a reflecting telescope, that magnified 80 times. The telescope was supported by a polar axis placed in the meridian, and on a strong stand, loaded with weight, which made it keep its position very steady. | 1769 July 24 | Time per Clock. | Difference of R. A. between the D's limbs and *'s. | |--------------|-----------------|--------------------------------------------------| | | h ' " | h ' " | | 19 39 33 | - - - | | | 39 43 | 19 43 32½ | | | 47 13 | 51 13 | | | 47 24½ | 51 25 | | | 47 36 | 51 38 | | | 20 5 11 | 20 9 35½ | | | 5 21½ | 9 48 | | | 5 34 | 10 00 | | | 18 13½ | 22 57½ | | | 18 25 | 23 9 | | | 18 36 | 20+ | | | 18 48 | 32 | | | 20 19 00:: | 44½ | | | 20 25 17+ | 30 12 | | | 28 | 33½ | | | 39+ | 35 | | | 51 | 46 | | | 26 3 | 30 59 | | | 33 54 | 39 2 | | | 34 5 | 39 13 | | | 34 40 | 39 48 | | | 41 37 | 46 6 | | | 41 48½ | 47 7½ | | | Clouds | 47 19 | | | Cl. | 30½ | | | 20 42 23½ | 47 42½ | After these, it got so hazy that I could not see the star. | N. B. The * passed along the wire parallel to the equator, or moved in a line parallel to the said wire. At the last observations the * was about 18 or 20' north of the D's center. ### Difference of Right Ascension between the ♀'s Limb and ⋆'s. | Time per Clock | Time per Clock | |----------------|----------------| | **July** | **July** | | ♀ - 21 | ⋆ - 21 | | D's 2d limb passed the wires vertical to the equator. | X ⋆ passed the wires vertical to the equator. | | h ' " | h ' " | | 18 30 3½ | 18 33 53- | | 30 15+ | 34 3 | | 39 41+ | 42 13½ | | 39 3½ | 51 26 | | 40 4 | 51 37½ | | 40 15+ | 51 49½ | | 40 27- | 21 58 39 | | 18 53 39½ | 18 55 47 | | 19 5 7 | 19 6 58 | | 18 | 7 10- | | 29½ | 7 20+ | | 41½ | 7 32 | | 5 53½ | 7 43+ | | 10 47 | 12 27½ | | 10 59 | 12 38½ | | 11 10+ | 12 49½ | | 11 21½ | 13 1 | | 11 34- | 13 12½ | | 19 17 00 | | | 12- | 18 42- | | 23 | 18 52½ | | 35+ | 19 4 | | 17 47 | 19 16 | | 22 42 | | | 22 53½ | 19 24 14 | | 23 4½ | | | 23 16 | 24 36½ | | 23 28+ | 24 48 | | 30 18 | | | 30 30½ | 31 40 | | 30 42- | 31 50 | | 30 53½ | 32 1 | | 31 5½ | 32 14 | | 21 51 4 | 21 53 27½ | | 51 15½ | 53 39+ | | 51 26 | 53 50 | | 51 37½ | 54 2 | | 51 49½ | 54 14 | | 21 58 39 | 22 1 14+ | | 58 50 | | | 59 1 | 1 36 | | 59 12+ | 1 48 | | 59 24 | 2 00 | | 22 5 50½ | 8 36 | | 6 1½ | 8 46 | | 6 12 | | | 6 24 | 9 10 | | 6 36- | 9 21 | | 13 9 | 16 18 | | 13 20 | 16 29½ | | 13 31 | 16 41- | | 13 42 | 16 53 | | 18 14 | 21 19+ | | 18 25 | 21 30½ | | 18 36- | 21 41½ | | 18 47 | 21 53 | | 22 18 59 | 22 5+ | | 28 12½ | 31 32- | | 28 23+ | 31 43+ | | 28 34½ | 31 54½ | | 28 46 | 32 5 | | 28 57+ | 32 18 | | 37 11 | 40 43- | | 37 22+ | 40 54½ | | 37 33+ | 41 4½ | | 37 44½ | 41 17 | | 37 56½ | 41 29 | N.B. In all these observations the ⋆ moved parallel to the equator. At the beginning of the observations the ⋆ was North of the ♀'s center about 13'. At 19h.47' when I left off to take the occultation, the ⋆ was but little North of the ♀'s center; by estimation 3 or 4'. The differences of A.R. after the occultation are very accurate, the ♀ being near the meridian, leaving the ⋆ nearly in a right line from her center. Immediately after these, it began to get foggy. Difference of Right Ascension between the D's Limb and *'s. | Time per clock. | |-----------------| | **July** | | 21 | | D's 2d limb passed the wires vertical to the equator. | A star of the 5th mag. passed the same vertical wires. | | 19 33 33½ | 19 34 38 | | 33 45+ | 34 49 | | 33 56+ | 35 0½ | | 34 8 | 35 12 | | 34 20+ | 35 24 | | 41 5+ | | | 41 16½ | 42 9 | | 41 28 | 42 20½ | | 41 40— | 42 32 | | 41 52 | 42 43+ | | 46 11 | 46 56½ | | 19 46 23+ | 19 47 8 | Left off to take the occultation. | Time per clock. | |-----------------| | **August** | | 16 | | D's 1st limb passed the wires vertical to the equator. | A bright spot in the D moved along the directing wire, or wire parallel to the equator, and the * followed about 6' North of D's center. | | h ' " | h ' " | | 18 4 30— | - - - | | 4 43 | - - - | | 4 55 | 18 25 1+| | 5 6 | 25 12 | | 5 18 | 25 23 | | Cloudy immediately after. | ### Difference of Right Ascension between the D's Limb and *'s. | Time per clock. | | |-----------------|---| | **1769** | | | **Sept.** | | | **2—15** | | | **D's 2d limb passed** | **Pifces passed** | | **the wires vertical** | **the same vertical wires.** | | **to the equator.** | | | **19 45 7—** | | | **19—** | | | **31** | | | **42½** | | | **45 54** | | | **19 54 17½** | **19 56 50** | | **30** | **56 2—** | | **42½** | **13** | | **53** | **23+** | | **55 5** | **57 34+** | | **then cloudy** | | | **20 29 16½** | **20 30 44** | | **28** | **30 56** | | **40+** | **31 8—** | | **51½** | **31 19** | | **30 3½** | **31 30** | | **34 33+** | **36 53+** | | **45+** | **36 5** | | **58—** | **16+** | | **35 9** | **27** | | **35 20½** | **36 38+** | | **41 13+** | **42 33** | | **25½** | **44+** | | **38—** | **48½** | | **42 0½** | **55+** | | **46 16+** | **43 7—** | | **28+** | **46+** | | **40** | **47 41** | | **51½** | **47 52** | | **47 3½** | **48 3½** | | **50 57—** | **51 49** | | **51 8** | **52 0** | | **51 20½** | **52 12** | | **56 39** | **57 23** | | **56 50+** | **57 33½** | | **57 1½** | **57 45+** | **Note.** In all these observations the * was often tried if it would keep the wire parallel to the equator, after moving it off the wire, and bringing it on again (by means of the vertical screw). For in these observations I was obliged to bring the star more Southward after I had made it keep the wire, before I brought it back for the D; otherwise the D's center would not follow through the field of the telescope; and I always found that it returned again to keep the wire with great accuracy: the wires very seldom wanting any alteration. **The * about 18' South of the D's center.** **The * by estimation 24' South of the D's center.** In these the D's center and * nearly at the distance of the field of the telescope, or as near the ends of the wires as the D's limbs would admit of. ### Difference of Right Ascension between the D's Limb and *'s. #### Time per Clock. | Sept. | D's 2d limb passed the wires vertical to the equator. | 16 Pisces passed the same vertical wires. | |-------|------------------------------------------------------|------------------------------------------| | 21 | 4 14+ | | | | 26 | | | | 38 | | | | 49 | | | | 5 1 | | | 20 | 24 34 | | | | 24 47+ | | | | 24 59½ | | | | 25 12 | | | 20 | 31 54- | | | | 32 6 | | | | 32 18½ | | | | 37 27 | | | | 37 38½ | | | | 57 51½ | | | 10 | 42 51- | | | | 43 4 | | | | 17 | | | | 29 | | | | 43 41- | | | 20 | 50 55- | | | | 51 7½ | | | | 58 29 | | | | 58 42 | | | | 58 56+ | | | | 59 8 | | | 20 | 59 21 | | | 21 | 1 | | | | the * 2" after the D's limb. | | | 21 | 2 | | | | The D's limb and * equal in A.R. as near as could be judged. | | | 21 | 3 35 | | | | The D followed the * 15" in time. | | | 21 | 7 50 | | | | Clouds Clear | | #### Time per Clock. | Sept. | 16 Pisces passed the wires vertical to the equator. | D's 2d limb passed the same wires. | |-------|-----------------------------------------------------|-----------------------------------| | 22 | 23 41 | 22 27 14 | | | 54 | 27+ | | | 24 6+ | 40+ | | | 17+ | 52 | | | 24 29½ | 28 4+ | | | 30 47 | 34 40 | | | 31 1- | 53 | | | 13 | 35 6+ | | | 25* | 18 | | | 31 37 | 35 30+ | | | 43 19½ | 47 42 | | | 33 36 | 54½ | | | 44 | 48 6½ | | | 22 43 56 | 22 48 19+ | | | 22 51 32+ | 22 56 15- | | | 45½ | 28 | | | 58 | 41- | | | 52 9+ | 52½ | | | 52 21½ | 57 5+ | | 23 | 2 56- | 23 8 7- | | | 3 9- | 20 | | | 22+ | 32 | | | 33+ | 44½ | | | 3 45+ | 8 57 | | | 15 16- | 20 55 | | | 29 | 21 9- | The Star was to move along the equatorial wire in all these observations, and I look upon the whole to be very good; particularly those after the occultation, as the difference of declination of the D's center and Star was by estimation not more than 4 or 5', nor even so much at the last observations. Q q q 2 Difference of Right Ascension between the D's Limb and *'s. | Time per Clock. | |-----------------| | **Sept.** | | **20** | | 16 Pifces passed the wires vertical to the equator. | | h ' " | | 23 15 41+ | | 41+ | | 16+ | | 48 4 | | 16+ | | 29+ | | 23 48 53 | | 0 3 16 | | 28+ | | 41 | | 3 53 | | cloudy | | D's 2d limb passed the wires vert. to the equator. | | h Leonis passed the same vertical wires. | | 2 52 2 | | 15½ | | 28— | | 39— | | 52 50½ | | 2 58 3 | | 15½ | | 28— | | 39+ | | 58 51— | | 3 3 54 | | 4 6½ | | 19— | | 30 | | 4 42½ | | 3 15 10— | | 22+ | | 34½ | | 45½ | | 15 57+ | | 23 21 12+ | | 33 | | 21 46— | | 54 58½ | | 55 25 | | 37 | | 23 55 48½ | | 0 10 44½ | | 10 58 | | 11 11 | | 11 23 | | 0 11 35 | | 2 54 53 | | 55 16½ | | 55 28+ | | 55 38 | | 3 0 41— | | 0 52½ | | 1 4— | | 1 15½ | | 3 1 27— | | 6 18½ | | 30+ | | 43 | | 52 | | 7 5 | | 17 12 | | 24 | | 36+ | | 47 | | 17 58½ | At these observations the Star followed the D's center along the wire parallel to the equator. Difference of Right Ascension between the D's Limb and *'s. | Time per Clock | |----------------| | | | 1769 Sept. | D - 25 h ' " | h ' " | |----------------|-------------|------| | | 3 21 9+ | 3 23 0 | | | 22 | 11 1/2 | | | 34 | 24- | | | 45 1/2 | 34 | | | 21 57 | 23 46 | | | 27 38 1/2 | 29 15 1/2 | | | 51 | 27 | | | 28 3 | 39 | | | 28 15- | 50 | | | 3 28 26 | 30 1/2 | | | 34 49 1/2 | | | | 35 2 | 36 2 3/2 | | | 14 1/2 | 36 35 | | | 25+ | 36 46 | | | 35 37 | 36 57 | | | 3 44 Clo. | | | | 3 55 11 | | | | 24- | 3 56 6 | | | 34 | 18 | | | 47 | 28 1/2 | | | 55 58 | 56 40 | | | 58 29 1/2 | 59 6 | | | 42+ | 18 | | | 53+ | 29 | | | 59 5 | 59 41 | | | Then cloudy | | | | 4 15 | Clear | At these observations the Star followed the D's center along the wire parallel to the equator. At these observations the Star was about 4' north of the D's center. | Oct. | D - 16 h ' " | h ' " | |---------------|-------------|------| | | 4 9 18 | 4 12 10 | | | 9 31 | 22+ | | | 9 44 1/2 | 36 | | | 9 55+ | 48 | | | 4 10 8 | 4 13 1/2 | D passed the wires vertical to the equator. Difference of Right Ascension between the D's Limb and *'s. | Time per Clock | D's 2d limb passed the same wires | |----------------|----------------------------------| | 1769 Oct. | | | 4 16 40 | 19 51 | | 16 52+ | 4 | | 17 4 | 16½ | | 16 | 28 | | 4 17 28 | 20 40½ | | 22 50 | 26 14 | | 3 | 27 | | 15 | 40 | | 26 | 5½ | | 23 38 | 27 4 | | 29 33 | 23 11 | | 46 | 24 | | 58 | 37 | | 9 | 59 | | 30 21 | 34 1 | | 4 54 47 | 21 | | 59½ | 33 | | 11½ | 46+ | | 23 | 57 | | 55 35+ | 5 0 10+ | | 5 4 52 | 9 47+ | | 5 4 | | | 5 15½ | 10 11 | | 5 5 27 | 5 10 24 | | 5 12 25 | 5 17 37½ | | 38 | 51- | | 50+ | 4- | | 13 2 | 15+ | | 13 14 | 18 27½ | | 5 2546½ | 30 26½ | | 2559 | 39½ | | 2611½ | 51- | | 26 23 | 31 2½ | | 26 35 | 31 16 | The * 10' south of the D's center, and the * passed along the middle wire. * moved along the lower wire. The * moved along the middle wire, after these I set the wires that the * passed exactly along the lower wire. The * 15' south of the D's center. Difference of Right Ascensions between the D's Limb and D's. | Time per Clock. | |-----------------| | 1769 Oct. | | D's 2d limb passed the wires vertical to the equator. | | D's 2d limb passed the same wires. | | h ' " | | 5 38 4+ | | 17+ | | 29 | | 41 | | 38 53 | | Then cloudy | | D's 2d limb passed the wires vertical to the equator. | | D's 2d limb passed the same wires. | | h ' " | | 3 39 55½ | | 8 | | 20 | | 30½ | | 40 42+ | | 46.32+ | | 45 | | 46 57 | | 47 8+ | | 47 20½ | | 55 3+ | | 16 | | 28 | | 38½ | | 55 50½ | | 4 1 21½ | | 4 53 9½ | | 20+ | | 53 32½ | | 5 1 41+ | | 1 54 | | 2 6 | | 2 16½ | | 2 30 | | 5 32 12 | The * about 6' north of the D's center.—The wires faintly illuminated and the * also appeared very faint. The wires very indifferently illuminated, and the * still appeared faint. These Numbers are a little dubious. Louds now began to interrupt the observations. Clear a few minutes before the D's limb, and * passed the wires at the same time; and at The D's 2d limb and * was equal in right ascension; the * by estimation 20' north of the D's center; then cloudy. The Transit of Venus. | Time per clock | Description | |----------------|-------------| | 1769 June 12-3 | Rain | | | Viewed the O's disk with the reflector (mag. 128 times), and saw nothing more than some large irregular black spots, with a black streak very near the edge of the O's limb on the Eastern side. | | | Adjustment of the nonius on the side of the telescope, for distinct vision for the contacts. Ditto for the micrometer. Ditto for the wire eye glass. | | 10 30 | Cloudy | | The air not quite clear | The external contact of Venus and the Sun's limb. | | Ditto more dense | The contact seemed to be formed by judging by their peripheries. Internal contact, the thread of light broke out. | | 12 12 | Cloudy | | 4 o 20 | The O's horizontal diameter, hazy. | | 12 21 | Cloudy | | 1 o 7 | to the left-hand of O | | 1 14 | to the right-hand of O | | 1 10 | left-hand | | | Venus's diameter. | | | After these, I immediately extended the glasses again for the Sun's diameter, but was prevented by clouds from doing anything farther. | Eclipses Eclipses of Jupiter's Satellites, Occultations of the \( \odot \) with the fixed *'s, and other Phænomena. | Time per clock | Apparent Time | |----------------|---------------| | 1769 | | | April | | | 5 | 13 49 36 | | June | | | 3 | 6 41 13 | | 11 | 6 59 25 | | 22 | 18 11 1 | | July | | | 1 | 9 20 52 | | 15 | | | 21 | 12 42 16 | | 20 | | | 21 | 13 56 18 | | Sept. | | | 20 | 10 16 20 | | 21 | | | 48 | 10 47 35 | | 57 | | | 10 | 55 46,6 | | Sept. | | | 25 | | | 4 | 17 8 2 | | Oct. | | | 16 | | | 3 | 15 23 33 | | Nov. | | | 9 | 9 44 42 | | or | | | 23 | 9 45 42 | | Nov. | | | 21 | | | 5 | 15 19 50 | Immersion 1st satellite of Jupiter. External contact of Venus's and the Sun's limb. Internal ditto, the thread of light broke out. The eclipse of the Sun began. Emersion 1st satellite of Jupiter. Twilight very strong, yet the satellites appeared well. Immers. \( \alpha \omega \) into the \( \odot \)'s enlightened limb. Emerf. of ditto from the \( \odot \)'s dark limb. Immers. of 1st \( \alpha \gamma \) into \( \odot \)'s light limb. Emerf. of ditto from \( \odot \)'s dark limb. Em. of 2d \( \alpha \gamma \) from \( \odot \)'s dark L. dubious to 3 or 4". Immers. of h \( \Omega \) into the \( \odot \)'s light limb. Twilight pretty strong, but not to render the observation in the least dubious. Emerf. of \( \delta \gamma \) from the \( \odot \)'s dark L. Immediately after, a very thin flying cloud passed over the \( \odot \); but I believe no part of it obstructed the observation. \( \gamma \times \) immersed into the \( \odot \)'s dark limb. The second is true to a second, but which of these minutes is true, was rendered dubious by accident. The \( \ast \), \( \Omega \), seemingly emerged from the \( \odot \)'s dark limb, but rendered a little dubious by flying hazy clouds. Observations of the ο, η, and *’s passing the Meridian, made with a Transit Instrument, the length of the Telescope 4 feet, having 2 Object Glasses, and magnifying 50 times. 1769 Sept. 24—21 The transit instrument, sent by the Royal Society, was brought to Cavan. 25—25 Began to set up the said instrument. 26—29 Examined the line of collimation of the transit instrument, and found it very much out. 27—30 Brought it very near, and found the level very good. Oct. 1—1 Brought the line of collimation quite exact (by many trials), using a distant object at the distance of about two miles. 2—2 At noon cloudy; in the evening it began to clear. January 1, 1750, the mean A.R. of the Pole * = 10° 42' 37" Annual preces. 158" then the preces. to this time = + 52° 00' Aberration in A.R. = + 8° 34' Nutation in A.R. = + 1° 30' Appt. A.R. the 2d of October 1769. Clock too slow for sidereal time by the observations of α Cygni made on the 30th of Sept. Clock loses in the interval of time between α Cygni’s passing the meridian and pole * Pole * transits the meridian, October 2d, at 23° 50' 28" by the clock. At this instant of time shewn per clock, I brought the middle wire to bisect the Pole *, and after took the passage of the following *’s over the meridian. | Time per clock | 1st wire | 2d wire | 4th wire | 5th wire | |----------------|----------|---------|----------|----------| | | | | | | | | | | | | | | | | | | Note, just before I brought the wire to the pole *, I set the axis of the transit instrument horizontal by the level; and at 3h 52', I examined it again by the level, and found it very exact. In the morning I placed a mark in the meridian about ½ of a mile North, and took particular notice what natural marks the middle wire cut on the summits of two hills, the one North about two miles, and the other South at a greater distance; these served after as complete marks in the meridian: and few meridians there are, I believe, of such a length. At first, before I could depend upon the instrument’s keeping its direction all night; I sent a man to place a candle in the center of the mark placed in the meridian, and it was very seldom that I found it vary in the least: what small difference might sometimes appear, was more probably owing to the placing of the candle, than the movement of the instrument. ### Observations made with the Transit Instrument. | Year | Oct. | 1st wire | 2d wire | Time per clock of passing the meridian | 4th wire | 5th wire | |------|------|----------|---------|---------------------------------------|----------|----------| | 1769 | 3 | | | | | | | | | 25° | 3 | 25° | 26° | 27° | | | | 14° | 4 | 45° | 46° | 45° | | | | 5° | 5 | 38° | 39° | 31° | | | | | | | | | | | 4 | Clouds | Clouds | | | | | | | 11° | 13° | | | | | | | 11° | 23° | | | | | | | 37° | 22° | | | | | | | 52° | 4° | | | | | | | 3½ | 5° | | | | | | | | | | | | | | 5 | 15° | 0° | | | | | | | 18° | 45° | | | | | | | 42½ | 29° | | | | | | | 5° | 37° | | | | | | | | | | | | | | 6 | | | | | | | | | 23° | 12° | | | | | | | 53° | 3° | | | | | | | 53° | 4° | | | | | | | 7° | 5° | | | | | | | 35° | 10° | | | | | | | | | | | | | | 10 | | | | | | | | | 3° | 12° | | | | | | | 22½ | 7° | | | | | | | 18° | 53° | | | | | | | 22° | 40° | | | | | | | 20° | 23° | | | | | | | 20° | 27° | | | | | | | | | | | | | | 11 | | | | | | | | | 2° | 46° | | | | | | | 59½ | 4° | | | | | | | 28° | 14° | | | | | | | 44½ | 29½ | | | | | | | | | | | | | | 12 | | | | | | | | | 9° | 50½ | | | | | | | 12° | 10° | | | | | | | 22° | 43° | | | | | | | 4° | 3° | | | | - Aldebaran - α Orion - Sirius - Θ’s 1st limb - Θ’s 2nd limb - Rigel - α Orion - Syrius - γ Aquilæ - α Orion - Syrius - Pole *, above the Pole - Aldeb. - Rigel - α Orion - Syrius - Procyon - Θ’s 1st limb - Θ’s 2nd limb - γ Aquilæ - α Aquilæ - D’s 1st limb - γ Capricorn - 1st C. ditto - Aldeb. - Rigel - α Orion - Syrius - Procyon Tried the line of collimation and the horizontal position of the axis, and found both correct. Observations made with the Transit Instrument. | Date | 1st wire | 2nd wire | Time per clock of passing the meridian | 4th wire | 5th wire | |------|----------|----------|----------------------------------------|----------|----------| | Oct. 9-13 | | | | | | | | 38 14+ | 18 38 | 59½ | 39 44½ | 29— | | | 55 42 | 5 28— | 22 57 14— | 57 59 | 58 44+ | | | 17½ | 2½ | 4 2 48— | 3 32 | 4 17 | | | 31 + | 16— | 42 1— | 45 | 30— | | | 45 | | | 3½ | 50 | | | 1½ | 6 26 | 31+ | 15½ | — | | Oct. 10-14 | | | | | | | | 52½ | 51 39 | 12 19 27+ | 20 11½ | 20 56 | | | | 23 52 | 26— | 53 11+ | 53 58— | | Oct. 15-16 | | | | | | | | 19 6+ | 19 52— | 12 20 37+ | | | | | 45— | 29+ | 18 38 15— | | | | | | 41 47 | | | | | Oct. 16-19 | | | | | | | | 28— | 12½ | 12 23 58 | | | | | 36 22 | 7— | 18 37 52 | | | | | 24+ | 9— | 4 40 54 | | | | Oct. 19-20 | | | | | | | | 47 | 35 32 | 12 36 17½ | | | | | 14½ | 59— | 18 36 44 | | | | | | 7+ | 2 30 56 | | | | | | 2 | 3 19 49— | | | | | | 59 48 | 4 0 33 | | | | | | 00½ | 4 39 46— | | | | | | 26 | 13+ | | | | | | 4 28½ | 5 6 5 | | | | | | 8 48½ | 9 37+ | | | | Oct. 20-21 | | | | | | | | 35 59 | 36 44+ | 12 37 29 | | | | | | 39 41½ | 40 26½ | | | | | | 4 0 11+ | 59— | | | | | | 4 9 30 | 10 14+ | | | | | | 5 21 5 | 51 | | | | | | 11 1 | 6 12 38 | | | | | | 2 24 | 8+ | | | | | | 6 29 | 10 | | | Notes: - Aquilae - D's 1st limb - Rigel - Orion - Syrius - Procyon - O's 2nd limb Very windy. - D's 1st limb Then cloudy. - O's 1st limb - O's 2nd limb - Aquilae - Ditto - O's 1st limb - O's 2nd limb - Aquilae - Orion - Cloudy - Aquilae - Ceti - Pleiadum - Aldebaran - Rigel - Orion - Gemini - Ditto - D's 2nd limb - O's 1st limb - O's 2nd limb - Rigel - Orion - Gemini - D's 2nd limb - Procyon - Pollux Observations made with the Transit Instrument. | Year | Month | Day | Time per clock of passing the meridian | Wire 1st | Wire 2nd | Wire 4th | Wire 5th | |------|-------|-----|--------------------------------------|---------|---------|----------|---------| | 1769 | Oct. | | | | | | | | | | 21 | | | | | | | | | | | | | | | | | | 22 | | | | | | | | | | | | | | | | | | 23 | | | | | | | | | | | | | | | | | | 24 | | | | | | | | | | | | | | | | | | 25 | | | | | | | | Nov. | | | | | | | - **Pegasi** - **Aldebaran** - **Orion** - **Aquilae** - **Procyon** - **Pollux** - **D's 2d Limb** - **Regulus** - **O's 1st Limb** - **O's 2d Limb** - **Aquilae** Examined the line of collimation, and axis with the level, and found both very good. From this time to the fourth of November cloudy, and rain. Great rains in the night. Observations made with the Transit Instrument. | Year | Month | Day | Wire | Time per clock of passing the meridian | Wire | Time per clock of passing the meridian | |------|-------|-----|------|----------------------------------------|------|----------------------------------------| | 1769 | Nov. | 5 | 1st wire | 35 4 | 13 35 50½ | 36 36½ | Cl. | | | | | 2nd wire | 38½ | 18 30 24— | 8½ | 53 | | | | | 4th wire | 58 8 | 18 58 54½ | 59 40 | | | | | | 5th wire | 42 | 1 29+ | 3 4½ | 3 52 | | | | | | 19 2 17+ | 14 6— | | | | | | | 19 13 20— | 19 18 25½ | | | | | | | 19 31 3 | 31 47½ | | | | | | | | | | Cloudy all the morning part. Tried the line of collimation, and the horizontal position of the axis, and found both exact. | Year | Month | Day | Wire | Time per clock of passing the meridian | Wire | Time per clock of passing the meridian | Venus's center | |------|-------|-----|------|----------------------------------------|------|----------------------------------------|----------------| | 1769 | Nov. | 8 | 1st wire | 11 46 48 | 47 32+ | 48 16½ | O's 1st limb | | | | | 2nd wire | 13 48 10 | 50 26 | 51 12+ | O's 2d limb | | | | | 4th wire | 28 10 | 18 28 55½ | 29 40 | α Aquilæ | | | | | 5th wire | 7 17— | 8 ½ | 31— | β Aquarii | | | | | | 20 44 | 21 29— | 20 22 14 | 58½ 23 43+ | | | | | | 18 29+ | 19 15 | 22 20 0½ | 20 46 | δ Pegasi | | | | | | 23 13 | 22 23 58— | 24 42 | γ Piscium | | | | | | | | | D's 1st limb | | | | | | | | | 19 Piscium | O's 1st limb O's 2d limb α Aquilæ β Aquilæ γ Pegasi δ Pegasi γ Orion δ Orion α Aquilæ α Arietis D's 1st limb γ Pleiadum α Aldeb. Observations Observations made with the Transit Instrument | 1st wire | 2d wire | Time per clock of passing the meridian. | 4th wire | 5th wire | |----------|---------|----------------------------------------|----------|----------| | Nov. | | | | | | 6—14 | | | | | | 25 36 | Clouds | | | | | 39 | 25 | | | | | 22 36 | 23 25½ | | | | | 8—15 | 8 53+ | | | | | 24—16 | | | | | | 40 12 | 0 41 | | | | | 54½ | 40½ | | | | | 54½ | 39 | | | | | 9 32½ | 10 19 | | | | | 36 24 | 37 13 | | | | | 8—17 | | | | | | 7 33½ | 19 | | | | | 12 2½ | 47 | | | | | 38 31+ | 39 19+ | | | | | 6—21 | | | | | | 37 33 | 38 21 | | | | | 6 4 | 6 50 | | | | | 48 | 4 27 | | | | | 10 1½ | 10 47 | | | | | 8—22 | | | | | | 58 10 | Clouds | | | | | 58 56 | Cloudy | | | | | 24—23 | | | | | | 2 ½ | 40 | | | | | 22 17 | 1½ | | | | The position of the instrument in the morning was about a second (in the equator) too much Eastward for Stars to the South of the Zenith. * Occasioned by a fluttering more than common. Observations made with the Transit Instrument. | Year | 1st wire | 2d wire | Time per clock of passing the meridian | 4th wire | 5th wire | |------|----------|---------|---------------------------------------|----------|----------| | 1769 | | | | | | | Nov. | | | | | | | 8—24 | | | | | | | | | | | | | | Dec. | | | | | | Packing up the Instruments. Tried the line of collimation, and found it good. Sent off the Instruments for Dublin. Charles Mason.