The Rutherfurd Photographic Measures. 129 



Table XVII. — Parallax Equations. 

 Comparison Stars 64 and 6. 



Residuals. 

 Plate. Scale. Arc. 



1 i.oox — 1.142/ — I.84II +1.74 = +0.46 +o // .i3 



2 1. 00 — 1. 13 — 1.87 +1.74 = +0.39 + -ii 



3 1. 00 — 1. 13 — 1.87 +0.23 = — 1. 12 — .31 



4 1. 00 — 0.08 — 1.94 +1.53 = — 0.23 — .06 



5 1. 00 — 0.04 — 1.S5 +1.87 = +0.27 + .08 



6 1.00 — 0.04 — 1.S5 +1.14 = — 0.46 — .13 



7 1. 00 — 0.04 —1.83 +2.52 = +0.96 + .27 



9 1. 00 +0.88 — 1.90 +1.08 = — 0.86 — .24 



10 1. 00 +0.89 — 1.93 +0.97 = — 1.03 — .29 



11 1. 00 +0.90 —1-93 +2.10 = +0.10 + .03 



12 1. 00 +0.90 — 1.93 +2.05 = +0.05 + .01 



13 1.00 +0.90 —1-93 +3-5i=o +1.51 + -42 



15 1. 00 +1.42 +1-99 —3-72 = o +1.42 + .40 



17 1. 00 +I-45 +1-94 — 5-74 = —0.69 — .19 



19 1. 00 +I-45 +I-93 —5.26 = —0.23 — .06 



20 1.00 +1.45 +1.93 —5.57 = —0.54 — .15 



[vv] =9. Si 



Normal Equations. 

 + 16.0000.1;+ 6.64003/ — 14.8800IT+ 0.1900 = 

 • +16.1850 + 9.3353 —25.1545=0 

 + 58.0200 — 78.1820 = 



Solution. 

 In units of 2d dec. place of scale. In Arc. 



II = + 1.8602 ± 0.1143 II = + o // .52ii db o // .0320 

 y= — 0.2695 ±0.2073 y= — o .0755 ±0 .0581 

 a; = + 1.8299 ± 0.2276 x = + o .5126 ±0 .0638 



Scale. Arc. 



Probable error of one equation = ± o // .5859 = ± o // .i64i 



