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Show .,. "tr‘m'ro FIND A TRUE MERIDIAN. 5 A MANUAL OF LAND SURVEYING}. \ AZIMUTH OBSERVATIONS. l cirggagngg‘ Horizonta Altitude of up- Eggigg cle for Mark. of sun. Standard per limb. Time. 0.0 . 36° 01%;" 9.05.45 ‘ 141° 081/2' REMARKS. in courthouse yard. Transit over stone post set se. hou pola. on public school Mark is cu- ........................ 44° 00' ' Latitude................... ..................... 80° Temperature . ............... 28.4 Barometer ............ Center of sun is azimu COMPUTATION. dif. of time ..... Declination, corrected for ... ...... _ ......... ... or z ...... " Cob .......... Apparent altitude of upper lim ............. Semi-diameter of sun ......... ...... ......... App. altitude of center of sun ............ ... ... Refraction ............... ............ ... ... sun True alt. of center of .............. s ll H II p 54° 15' ll ll Co-altitude of sun, or p ...... 78° 56' z 179° 11' 89° 3515' II II II ll S is 1ES--p 1}S--s ‘ P 5 = 11° 04' = 78° 56' = 36° Olt' 151%" = = 54° 15' _ - . -- 35° 20? log sin ............ " 43° 351? " " ,. . . . 9.762267 9.838543 ; '0.090672 .143066 = 9.917274 = = 55° 4417' log sin. tZ ........... point. north the reckoned from = 111° 29' south 31' reckoned from the Azimuth of sun = 68° , Z ' point. considere mbering that declinations being determined by reme as they are north or according and latitudes are + or -- of the term will have the sign south, and that the first ond will be oppored to ' the sec declination, while the sign of that of. the latitude. EXAMPLE. and a: 35° 45' (see p. 126). Let d = 11° 04', l=44° 00', ‘ s1n 11 I O 04 :Then cos Z: + cos 44° cos 35° 45' ' -tan 44° tan 35° 45' Applying logarithms, 19.834548 §Z mb ‘ metrical functions in the secondofmethe terms as wholes d positive, the signs == = = 35° 45' 46° 00' 54°15 46° 00' nridge, 0010., makes the Mr. J. G. Mc Elroy, of Brecke following suggestion : - finding z, his northern -"The Sun may be utilized by __ sin (1 . + tanl tan a, W i = Z cos m fro h, az1mut ation, a his corrected altiwhere d is the sun's declin itude. The five trigonotude, and l the observer's lat er will always be ' = azimuth of cupola 141° 08!; -- 68° 31' = 72° 3713 t at the station with horion Schoolhouse. A. transi ' 'and pointing at the cupola zontal circle reading 72° 371 point in the true meridian. when returned to zero will 9520 cos Z = + 0.32880 - 0.6 30' = -- 0.36640 = cos 111° the obg was S. 68° 30' E., since ' Hence the sun's hearin e morning. servation was taken in th azimuth deduced on p. 126 You will notice that the mputation, it th greater care in the co I differs by 1'. Wi e near, which is correct to th will agree with mv result est minute." formula used by Mr. Mc e th of on ti va ri de e th r Fo 1899. n Engineers' Annual" for ' Elroy, see the "Michiga |
