OBSERVATIONS WITH THE ZENITH TELESCOPE. 



289 



Then we have 



Aa 



2pn 



A,,. 



_ ZpTn 



2p -Zpf* 



Check Xpvv — Xpnn — (Xpn) Aa — (XpTn) Afi 

 Aa for 1875 will be the above Aa + (1875 — t ) A(i. 

 An example follows which will illustrate the various steps in the process 



Star. Assumed Coordinates and proper motion for 1875.0. 



B A C 3140 a = 9» 7™ 10-.87 /t = + .0056 



«' = + .008 



o= 9" 7 m 10".87 

 rf = 540 32' 11".1B 





Catalogue. 



T 



t 



No. 

 Obs. 



v." 



n 



P 



pi 



pn 



T 



pT 



p'fn 



V T> 



V 



1 



Bradley 



1755 



54.2 



8 



+ .0050 



—0.009 



.3 



—13.74 



—0.0027 



—103.22 



—30.97 



+0.2790 



+3199.20 



—0.063 



2 



Piazzi 



1800 



04.83 



9 





+0.201 



.08 



+ 0.39 



+0.0209 



— 52.59 



— 4.21 



—1.0902 



220.92 



—0.300 



3 



Groombvidge 



1810 



08.8 



6 





—0.244 



.2 



1.76 



—0.0488 



— 48.02 



— 9.72 



+2. 3668 



471.42 



+0.208 



4 



Dorpat 



1814 



14.11 



2 





—0.212 



.2 



2.82 



—0.0424 



— 43.31 



— 8.66 



+1.8444 



376.71 



+0.179 



5 



Pond 



1830 



31.54 



13 





+0.070 



.4 



12.02 



+0.0280 



— 25.88 



—10.35 



—0.7280 



269.36 



—0.091 



(! 



Madras 



1835 





11 





-(-0.042 



.3 



10.50 



+0.0126 



— 22.42 



— 0.73 



—0.2814 



150 08 



—0.061 



1 



Riimker 



1830 





6 





—0.040 



.2 



7.20 



—0.0080 



— 21.42 



— 4.28 



+0.1720 



92.02 



+0.022 



8 



Armagh 



1840 



34.74 



2 





•fO. 000 



.1 



3.47 



+0.0006 



— 22.68 



— 2.27 



—0.0138 



52 21 



—0.025 



9 



Gilliss 



1840 



41.85 



1 



-| .011 



—0.010 



.05 



2.09 



—0.0005 



— 15.57 



— 0.78 



-| 0.0080 



12 48 



—0.005 



10 



Edinburgh 



1842 



42.18 



5 





+0.225 



.5 



21.09 



+0.1125 



— 15.24 



— 7.62 



—1.7100 



115.52 



—0.239 



11 



Oeltzen's Arg'er 



1843 



42.12 



1 





—0.118 



.05 



2.11 



—0.0059 



— 15.30 



— 0.77 



+0.0944 



12.24 



+0.104 



12 



Greenwich 



1845 



44.87 



6 



+ .011 



—0.186 



.7 



31.41 



—0.1302 



— 12.55 



— 8.79 



-1-1.0308 



110 88 



+0.173 



Id 



Radcllffe 



1845 



47.9 



7 



+ .004 



+0.103 



.9 



43.11 



+0.0927 



— 9.52 



— 8.57 



—0.8858 



81.70 



—0.114 



14 



Paris 



1845 



41.6 



18 





—0.043 



1.1 



45.70 



—0.0473 



— 15.82 



—17.40 



+0.7482 



274 92 



+0.028 



15 



Poulkova 



1855 



47.80 



1) 



+ .0056 



—0.080 



1.0 



47.80 



—0.0800 



— 9.62 



— 9.02 



+0.8250 



92.16 



-1-0.075 



16 



Greenwich 



1860 



59.5 



3 



+ .004 



—0.013 



.9 



53.55 



—0.0117 



+ 2.08 



+ 1.87 



—0.0247 



3.99 



+0.010 



17 



Radcllffe 



1800 



59.2 



4 



+ .004 



—0.003 



.4 



23.68 



—0.0012 



+ 1.78 



-1- 0.71 



—0.0021 



1 26 



.000 



18 



Yarn all 



1800 



7SJ.5 



4 





—0.112 



.7 



50.75 



—0.0784 



+ 15.08 



+10.50 



—1.1872 



160.00 



+0.117 



19 



Brussells 



1865 



66.00 



4 





-| -0.032 



1.1 



72.60 



+0.0852 



+ 8.58 



+ 9.44 



-1-0.3008 



80.84 



—0.031 



20 



A. G. Zones 



1875 



75.2 



2 





—0.131 



.3 



22.56 



—0.0393 



+ 17.78 



+ 5.33 



—0.0943 



94.34 



+0.138 



21 



Paris 



1875 



81.2 



2 





| 0.039 



.3 



24. 36 



+0.0117 



+ 23.78 



+ 7.13 



+0.2709 



168.98 



—0.028 



22 



Stockholm 



1875 



75.58 



3 





—0.130 



.4 



30.21 



—0.0520 



+ 18.11 



+ 7.24 



—0.9300 



130.32 



+0.137 



23 



Madras 



1878.40 



78.61 



1) 





| 0.098 



.8 



39.31 



-1-0.0490 



+ 21.19 



+10.00 



-1-1.0388 



224 72 



—0.089 



24 



Greenwich 



1880 



84.24 



7 



-| .0050 



+0.045 



2.9 



| 244.30 



+0.1805 



+ 26.82 



+77.78 



+3.5010 



2085.04 



-0.032 

















13.58 



779.71 



—0.0007 





— 0.08 



-1-5.5322 



+8481.37 











1 







Up 



Ipt 



Zpn 



2pT 



ZpTn 



^pT> 





«n 



779.71 



57.42 



13.58 

 Weighed moan date = 1857.42 



A« == -0- 06 07_ = _ aa0045 



lo.Oo 



2pv 2 ss 



0.1277 



2p?i 2 = 



0.1815 



(2pn) Aa = 



— 0.0003 



(^2' 2 ) Aft = 



— 0.0036 



Check 



0.1276 



■V' 



5.5322 



848E37 



+ 0/00065 



Art I876 = —0.0045 + (0.00005 X (1875 — 1857.42)) = + 0.0009 



Assumed a 

 Final value 



9" 7™ 10". 87 

 9" 7"' 10 s .877 



Assumed ft + 0.0050 

 Pinal value + 0.00625 



