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 43

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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 43

more nearly so than at the beginning of the operation. 
   The adjustment may be tested by repeating the process; i.e., by observing another star near the zenith and obtaining a closer approximation to Δt, and then comparing the computed [strikethru]the computed[/strikethru] clock time of transit of a slow-moving northern star with the observed clock time of transit. If the star transits apparently too late, the objective is too far west, if the star is above the pole, and too far east if the star is below the pole. The azimuth screw may then be used to reduce the azimuth error.
   If from previous observations the clock correction is known within, say, five seconds, the foregoing process of approximation may be commenced by using a northern star at once instead of first observing a zenith star.
   Or, the clock correction being known approximately and the instrument being furnished with a graduated arc by means of which a small horizontal angle may be measured, the

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more nearly so than at the beginning of the operation. The adjustment may be tested by repeating the process; i.e., by observing another star near the zenith and obtaining a closer approximation to Δt, and then comparing the computed [strikethru]the computed[/strikethru] clock time of transit of a slow-moving northern star with the observed clock time of transit. If the star transits apparently too late, the objective is too far west, if the star is above the pole, and too far east if the star is below the pole. The azimuth screw may then be used to reduce the azimuth error. If from previous observations the clock correction is known within, say, five seconds, the foregoing process of approximation may be commenced by using a northern star at once instead of first observing a zenith star. Or, the clock correction being known approximately and the instrument being furnished with a graduated arc by means of which a small horizontal angle may be measured, the