Ball, R[obert] S[tawell], Sir, 1840- [from old catalog] · New York, H. Holt and company · leaf 51
espectively. Let </> be the latitude and 0 thedeclination of the star. Then the zenith distance of the star at lower cul-minate is z s, but zs= zp + ps = 90 -^ + 90 — 2 = 180 — <p — d. Now, in order that a star be visible it is necessarythat its zenith distance be less than 900. Hence for… … visible at lower culmination it will a fortiori be visibleat upper culmination. Now suppose a southern star at t (fig. 13). Itszenith distance is z t, but z t=pt—p z =90 + 5-(90-4>) The Meridian Circle. 33 Hence for the star to be visible at upper culminationwe must have $ + <b <9o°or…
Astronomy
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