Find the sidereal clock reading and the altitude at which Arcturus will be in Petersburg (a Bootes, a = 14h12m, b = + 20) at the moment it crosses the eastern part of the first vertical.
The world axis PP1 runs at an angle of 60 ° to SN, and the parallel of KL is + 20 ° from the equator EQ. The intersection of KL with CZ gives us point D. On KL, as on a diameter, draw a circle and a straight line DM1, perpendicular to KL, up to the intersection with this circle MK1L; then РKFM1 = t = 262 = 18h48m and the required hour angle will be. To find the height of the luminary, draw a straight line GH parallel to SN through point D and measure it with a protractor INH or, anyway, PNCH = h = 23o. Knowing the hour angle t and right ascension a, we will also find the sidereal time at this moment, which will be s = t + a = 18h48m + 14h12m = 9h0m. Thus, at the moment Arcturus crosses the eastern part of the first vertical in St. Petersburg, sidereal time will be 9 hours, and the height of Arcturus will be 23о.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.