DIY History | Transcribe | Scholarship at Iowa | Theory of the astronomical transit instrument applied to the portable transit instrument Wuerdemann no.26: a compilation from various authorities, with original observations by Harry Edward Burton, 1903 | Theory of the astronomical transit instrument applied to the portable transit instrument Wuerdemann no. 26: a compilation from various authorities, with original observations by Harry Edward Burton, 1903, Page 89

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Theory of the astronomical transit instrument applied to the portable transit instrument Wuerdemann no.26: a compilation from various authorities, with original observations by Harry Edward Burton, 1903

Theory of the astronomical transit instrument applied to the portable transit instrument Wuerdemann no. 26: a compilation from various authorities, with original observations by Harry Edward Burton, 1903, Page 89

   For stars whose declination <80° it will be sufficiently accurate to take (sin I[subscript]0[/subscript][superscript]s[/superscript])/(sin I[subscript]δ[/subscript][superscript]s[/superscript]) = (I[subscript]0[/subscript][superscript]s[/superscript])/(I[subscript]δ[/subscript][superscript]s[/superscript]) 

Then (1) becomes (I[subscript]0[/subscript][superscript]s[/superscript])/(I[subscript]δ[/subscript][superscript]s[/superscript]) = cos δ ; 

therefore (I[subscript]0[/subscript][superscript]s[/superscript]) = (I[subscript]δ[/subscript][superscript]s[/superscript] cos δ). 

   Use of the Wire Intervals.
   It may happen thru unfavorable weather or some other cause that the transits over only a part of the wires are observed; but such observations may be reduced by means of the wire intervals. If we take the transit of a star over C[subscript]3[/subscript], for example, and fail to get the time of transit over the corresponding wire E[subscript]3[/subscript], we may still make use of the time of transit over C[subscript]3[/subscript], in finding the time of transit over the middle wire, by adding to it the wire interval of C[subscript]3[/subscript] and D[subscript]3[/subscript] for the declination of the star.

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For stars whose declination <80° it will be sufficiently accurate to take (sin I[subscript]0[/subscript][superscript]s[/superscript])/(sin I[subscript]δ[/subscript][superscript]s[/superscript]) = (I[subscript]0[/subscript][superscript]s[/superscript])/(I[subscript]δ[/subscript][superscript]s[/superscript]) Then (1) becomes (I[subscript]0[/subscript][superscript]s[/superscript])/(I[subscript]δ[/subscript][superscript]s[/superscript]) = cos δ ; therefore (I[subscript]0[/subscript][superscript]s[/superscript]) = (I[subscript]δ[/subscript][superscript]s[/superscript] cos δ). Use of the Wire Intervals. It may happen thru unfavorable weather or some other cause that the transits over only a part of the wires are observed; but such observations may be reduced by means of the wire intervals. If we take the transit of a star over C[subscript]3[/subscript], for example, and fail to get the time of transit over the corresponding wire E[subscript]3[/subscript], we may still make use of the time of transit over C[subscript]3[/subscript], in finding the time of transit over the middle wire, by adding to it the wire interval of C[subscript]3[/subscript] and D[subscript]3[/subscript] for the declination of the star.