A S T R 0 N 0 M IS C H E N A C H R I C H T E I!?+

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Schreibeu des Herrn Professors Airy Directors der CamEridger Sternwarte an den Herausgeber. Observatory Cambridge 1832. March 12.

The longitude OF Cambridge Observatory has been found AR. from Error of Day. Observed (by transmis8ion of chronometers) lo be 23"M of time East AR. BerLJahrb Lerl.Yshrb of Greenwich. Its aslroiiomical latifude is about 52' - 12' 50"; - - Jan. 22 -8 47 11,Il 3 1,k4 ;:33 mid for the compiitalion of the occiiltations: the ratio of 4- 23 8 46 9,51 10,05 f- 0,34 the earth's axes is assumed 10 be 297: 298. The transit 25 8 44 5,25 5,60 + u,3a clock has been corrected by a catalogue of principal dials, 27 8 41 58,91 59,51 + 0,60 Pehr. 2 9 35 37,92 38,40 in which the ,4R. is grea f er thon in UesseZ's catalogue by + 0948 4 8 33 32,35 32,79 0"18 of time. The Greenwich Mean Solar Time is de- -+ 0944 7 1 8 30 27,59 28,19 f 0,60 duced from the Cambridge Sidereal Time by means of the 9 8 28 28,31 28jti4 $- v,33 epochs in Delambre's solar Tables, aiid is converted into 14 8 23 46,41 15 8 22 Berlin Mean Time by addiiig 53' 34"2; this the Time 53,30 is 16 8 22 1,41 used in interpolating from the Berliner Jahrhucb. 19 8 19 34,98 Mean Error of the Sun's dR in the Berliner Jahrbuch. 20 8 18 49,17 1830 January, February, March, mean of %iob- 22 8 17 22,03 23 3 16 40,97 servulions . , -0ON28 ...... 24 8 i6 0,88 -4pri1, May, June, mean of 24 observgfions 0,23 - - March 5 it August, September, mean 26 observ. O,21 8 9,66 July, of - 6 October, November, December, mean of 29 3 10 51,07 7 8 10 34,57 observations 0,24 . . - ...... - 9 8 10 7,62 1831 January, February, March, mean of 30 obs. - 0,25 10 8 9 57,23 April, May, June, mean of 31 obscrvaiioiis . - 0,14 i July, August, September, mean of 46 observ. - 0,lS October, November, Uecember, mean of 40 Febr. 7 10 22 3,68 3,16 - 0,52 9 10 20 29,63 observations...... ,, . - 0117 29,03 - 0,60 14 0,57 If Bessds catalogue bad been used, the error8 mould - 15 - 0,33 have been .- 0,02; - 035; - 0,03, - 0,06; - 0,07; 19 - 0,61 +0,04; t 0,03; +0,01. This shews the accuracy oCBes 20 - 0,92 23 10 8 dscorrectioris ; and the agreement of different quarters 54,78 53,94 - 0,84 March 7 9 58 58,95 58,57 - 0,38 of the same Tear shews that there is 110 perccplible error 9 9 57 40,32 39$9 - 0,73 in the perihelion and the equation of the center. 01 the 10 9 57 2,85 difference between the two vears, a part (but not the .ciholc) is caused by the difference of my nutation (s"25) from July 7 BsssePs (~"98). 22 24 25 30 AR from Error of Aug. 15 Day. Observed AR. Berl.Jahrb. BerlJahrb. 23 - ---h I I1 Jon. 14 8 54 52,65 52,';7 -k (32 18 8 51 338 9,71 0,23 20 IW Bb 8 115 Rr. 224. I 16

The AR. of Juno Febr. 15 given by the observation was 1831 Oct. 23 Disappearance of 75 Tauri 23h 54‘ 3”OB W 15‘ 33”20; but I think this must have been 2“ wrong. Reappearance OF 8’ Tauri 0 14 14’86 Vesta is still bright, hut Juno is faint. Pallas last year Reappearance of 75 Tauri 0 26 1,15 was very faint: and the southern declination of Ceres was Disappearance of Aldebaran 3 6 52,49 so great that she soon became invisible. Reappearance of Aldebarati 4 13 32,40 Nov.26 Reappearance of Saturn’s center If BessePs catalogue bad been used, each OP the Errors I0 3 46,46 Dec. 17 Reappearance OF y Tauri would have been increased by +O”lS. 22 I1 41,54 Disappearance of Aldeharan 4 45 10,50 Occukations (given in Cambridge Sidereal Time) Dec. 22 Disappearance of Regulus 13 42 55,06 h I tI 1831 Jan. 26 Disappearance of f Geminorurn 6 38 30’60 1832 Jan. 20 Disapp.ofSaturii’scent.(uncert ) 5 17 6,48 June 1 Disapp.ofJup.center (mean of3obs.)Il 47 31,92 Reappearance (uncerfain) 6 28 7,49 Seappearance (mean of 3observ.) 18 54 27,79 Jan. 25 Disappearance of ~Librae 13 32 16,%2 Oct. 21 Disappearance of gg &ti 22 35 33,11 Reappearance 14 50 22,27 Reappearance 23 28 53,84 Febrio Disappearance OC Aldebaran I 58 46,49 Oct. 23 Disappearance of 8’ Tauri 23 36 47,45 Reappea ran ce 3 8 35,23 Disappearance of dz Tauri 23 47 16,05 March8 Disappearance of Aldebaran 11 9 20,65

Stars. Star’s AR. Star‘s N. P. D. .Berlin Mean Time. Moon’s AR. - a I I8 tI 0 # I/ 18- h I 11 0 I II f Gemin. 112 -56,IOts 71 57 0,28+ ” Jan.26 11 953,3+t 25 f 112 -156,71+&-{6199.r Jupiter(disapp.) 32449 12,60fe$-ONO013.t 10451 5,324- f-0,0002.t June 1 14 140,6+t 324 3 37,43+xr0,528i.t Jupiter (reapp.) 324 49 17,70+ef 0,0013.t 104 51 4,37+rfi0,0003.t June 1 15 8 25,6+l 324 38 52,54+~+0,5281.t &” Ceti (disapp.) 34 48 36’80 + e 52 17 54,804- f Oct.21 9 30 35,6+r 34 116,35+r+0,5891.t $” Ceti(reapp.) 34 48 36,SO + e 82 17 54,80+f Oct.21 102347,7ft 343237,99fs$.0,5899.t 6’ Tauri 64 44 34’90 + e 7425 4,374-f oct.23 102348,1+l 63 51 52,05fr+0,6299,t 8” Tauri (disapp.) 64 46 4,69 + e 74 30 29,99 f Oct.23 10 34 15,0+1 63 58 26,98$.~+0,6301.t PTauri (reapp.) 64 46 4,69-/-e 74 30 29,99 +f Oct.23 11 1 9,4ft 64 15 24,33+x+0,6303.t 75Tauri (disapp.) 64 42 36,D4+e 74 i27,78+f 0ct.23 1041 0,9-kt 64 242,72+r+0,6301.t 75 Tauri(reapp.) 64 42 35,04+ e 74 I27,784- f Oct. 23 11 12 53,s -ft 64 22 &,36 + xf 0,6305. t Aldehar. (disapp.) 66 34 16,5ife 7350 9,60ff Oct.23 13 53 18,8+i 66 4 4,31+~+0,6321.t Aldebar. (reapp.) 66 34 16,51 +e 73 50 9,60+f Oct. 23 14 59 47’8 4-t 66 46 6,99 fx+ 0,6328.t y Tauri 62 33 38,95 + e 74 47 11,164- f Dec.17 52241,2+t 62 11 10,18+zf0,6407.t Aldebaran 66 34 28,17+e 73 50 lO,O6+ f Dec.17 11 55 5,7+t 66 24 12,58+~+0,6490.t Regulus 149 51 14,25fe 77 12 52,58+$ Dec.22 20 31 42,6+t,150 6 36,36+z+0,5817.t 1832 yLihrae(reapp.) 231 31 54,75+s 104 13 8,044- f Jan. 25 19 25 17,7+2 231 41 39,24+x+0,4952.c YLibrae (disapp.) 231 31 54,75 + e 104 13 8,04+f Jan. 25 18 7 25,1+t 131 3 5,82+ x+0,4948.~ Aldebar. (disapp.) 66 34 22,20 + e 73 50 11,27 +f Feb.10 53253’84-1 65 5452,61+x+0,6051.t Aldebar. (reapp.) 66 34 22,20 f e 73 50 11,27 -/-f Feh.10 64231,1+t 6637 3,24+r+0,6066.t Aldebaran 66 34 14,85+e 73 50 11,9l+f March8 12 55 48,3+ t 66 55 50,05+x+0,5982.1 Stars. Moon’s N. P. D. Moon’s hor. eq. par. Moon’s semid. - 0 I I4 1831 f(iemin. 7’54 Oy0474. t (59‘ -O”80) - 71 30- +;&

Jupiter(disapp.) 104 1 27,67 +y-00,1254.t (56 2,121

Jupiter (reapp) 103 53 23,09 +y-00,1268.r (56 3~99) 0”Ceti(disapp.)

g’ Ceti(reapp.) m 8‘ Tauri

#2 Tauri(disapp.) 1'7 -Stars. -Moon's N. P. D. I-Moon's hor. eg. per. I- Mom's semid. 8' Tauri (reapp.)

73Tauri (disapp.)

75 Tauri (reapp.)

Aldebaran (disapp.

Aldebaran (reapp.)

y Tauri

Aldeba ran

Regulus

1832 rI,itirae (reappj

y Librae (disapp.)

Aldebaraii (disapp., Aldebaran (reepy.)

Aldebaran

e, x and y, are expressed in seconds of Rrcj t in seconds of time. The following equaIion8 are deduced from these by a process which (for most of them) is correct to 0"Ol.

1831 Jan. 26 Disapp. offGemin. + 4,49 = $0,871. e - 0,393 - f - 0,871 - x + 0,395 ay- 0,521. t + 0,339. rn - 0,965. June 1 Disapp.ofJupiter + 0,65 = +0,959.e + 0,152.f -0,959~~-00,1~3~~-~J486.~-O~161.m-~,g;~.n Reapp.ofJupiter + 9,23 = -0,806. e+ 0,557.f-k 0,806.~-0,557.y + 0,495. t - 0,526.m - 0,917.n Oct. 21 Disapp.ofE'Ceti -17,39 = $0,962.e$-0,233.f-0,962~~-0,233.~-00,523. t- 2,403.m - 0,984. n Reapp. ofg2Ceti - 12,23 = -0,548. e + 0,833 -ff 0,548. - 0,832 -y + 0,481, t - 1,330. nt - 0,984. Oct. 23 Disapp.of'd'Tauri $13,06 = $0,919. e + 0,288 .$- 0,919 - r- 0,287. y - 0,644. t - 2,747. m - 0,989. Disapp. ofPTauri + 9,47 = f0,665. e + 0,721 .f- 0,665.3 - @,721.y -- 0,331, t - 3,252. m - 0,989 ,n Reapp.ofd*Tauri + 4,43 = -o,18I.e+OJ982.f $.0,181.~-00,982.y f 0,234.t-22,051.nt-00,989,R Disapp. oF75Tauri - 0,07 = +0,246. e - 0,967. f - 0,246 - x 0,967. y - 0,273. t f 1,889. m - 0,989. Reapp.oF75Tau1-i - 6,71 == -0,729.e-O,649.$+0,729-.t:$.0,650.y$ 0,381.t+3,011. rn-0~989.~ Disapp. of Aldeb. + 6,52 = +0,954. e 3- 0,085 f - 0,954 - x - 0,083 - y - 0,593. t - 0,937. rn - 0,989. n Reapp, ofAldeh. - 1,87 = -0,777. e + 0,585 .f+ 0,777 - 0,584.~+ 0,558. c - 1,140. rn - 0,989. Dec. 17 Reapp. ofy Tauri -20,74 = -0,899. e + 0,356 .f + 0,899 - x - 0,355.y -k 0,624. t + 1,114. na - 0,998. Disapp.ofAldeb. f- 3.14 = $-0,743.e+ 0,630.f-0,~43~~-~~629.~-0,405.t-11,210.rrp-~1,~~~.n Dec.22 Disapp. ofReg. - 1,85 = +0,909. e + 0,356 .f- 0,909 - * - 0,355- y - 0,583. t 4- 0,812. rn - 0,966. 1832 Jan. 25 Disapp. ofy Libr. + 4,98 = +0,794 e -+0,578 .f- 0,794. .t: - 0,579. j' - 0,470. t - 2,477. rn - 0,892. Reapp.ofyLibr. - 2,67 = -OJ958.e-0,I76.~f0,950.~~0,175.y~ 0,497.tf0,833.nt-0,892.~ Feb.10 Disapp.of.Aldeb. - 1,39 = $-0,943.e-0,174.f-0,943~~+0~1~5~y-0,591.t~0,909.na-~,~f~~~ Reapp.ofAldeb. - 0,16 = -0,869. e + 0,420 .f+ 0,869 x - 0,419.y + 0,576. t - 0,229. m - 0,971. March8 Uisapp. of Aldeb. 4- 0,38 = +O,SSS. e 4- 0,376 .f- 0,886 X - 0,375 +y- 0,487. t + 0,928. m - 0,963, G. B. Airy.