Page:Newton's Principia (1846).djvu/480

1680, Dec. 12 21 24 26 29 30 1681, Jan. 5 9 10 13 25 30 Feb. 2 5	Time		Sun's Longitude	Comet's
	Appar.	True.		Longitude.	Lat. N.
	h.   ″ 4.46 6.32½ 6.12 5.14 7.55 8.02 5.51 6.49 5.54 6.56 7.44 8.07 6.20 6.50	h.   ′   ″ 4.46.0 6.36.59 6.17.52 5.20.44 8.03.02 8.10.26 6.01.38 7.00.53 6.06.10 7.08.55 7.58.42 8.21.53 6.34.51 7.04.41	°   ′   ″ ♑   1.51.23 11.06.44 14.09.26 16.09.22 19.19.43 20.21.09 26.22.18 ♒   0.29.02 1.27.43 4.33.20 16.45.36 21.49.58 24.46.59 27.49.51	°   ′   ″ ♑   6.32.30 ♒   5.08.12 18.49.23 28.24.13 ♓   13.10.41 17.38.20 ♈ 8.48.53 18.44.04 20.40.50 25.59.48 ♉ 9.35.0 13.19.51 15.13.53 16.59.06	°   ′   ″ 8.28. 0 21.42.13 25.23. 5 27.00.52 28.09.58 28.11.53 26.15. 7 24.11.56 23.43.52 22.17.28 17.56.30 16.42.18 16.04. 1 15.27. 3

To these you may add some observations of mine.

1681, Feb. 25 27 Mar. 1 2 5 7 9
	Ap. Time.	Comet's
		Longitude	Lat. N.
	h.   ′ 8.30 8.15 11. 0 8. 0 11.30 9.30 8.30	°   ′   ″ ♉   26.18.35 27.04.30 27.52.42 28.12.48 29.18. 0 ♊     0. 4. 0 0. 43. 4	°   ′   ″ 12.46.46 12.36.12 12.23.40 12.19.38 12.03.16 11.57. 0 11.45.52

These observations were made by a telescope of 7 feet, with a micrometer and threads placed in the focus of the telescope; by which instruments we determined the positions both of the fixed stars among themselves, and of the comet in respect of the fixed stars. Let A represent the star of the fourth magnitude in the left heel of Perseus (Bayer's ο), B the following star of the third magnitude in the left foot (Bayer's ζ), C a star of the sixth magnitude (Bayer's n) in the heel of the same foot, and D, E, F, G, H, I, K, L, M, N, O, Z, α, β, γ, δ, other smaller stars in the same foot; and let p, P, Q, R, S, T, V, X, represent the places of the comet in the observations above set down; and, reckoning the distance AB of 80⁷⁄₁₂ parts, AC was 52¼ of those parts; BC, 58⁵⁄₆; AD, 57⁵⁄₁₂; BD, 82⁶⁄₁₁; CD, 23⅔; AE, 29⁴⁄₇; CE, 57½; DE, 49¹¹⁄₁₂; AI, 27⁷⁄₁₂; BI, 52¹⁄₆; CI, 36⁷⁄₁₂; DI, 53⁵⁄₁₁; AK, 38⅔; BK, 43; CK, 31⁵⁄₉; FK, 29; FB, 23; FC, 36¼; AH, 18⁶⁄₇; DH, 50⁷⁄₈; BN, 46⁵⁄₁₂; CN, 31⅓; BL, 45⁵⁄₁₂; NL, 31⁵⁄₇. HO was to HI as 7 to 6, and, produced, did pass between the stars D and E, so as the distance of the star D from this right line was ¹⁄₆CD. LM was to LN as 2 to 9, and, produced, did pass through the star H. Thus were the positions of the fixed stars determined in respect of one another.