An introduction to astronomy: designed as a text-book for the use of students in college. By Denison Olmsted ...

PROBLEMS ON TEIlE CELESTIAL GLOBE. 27
76. To represent the calppearcance of the heavens at any time:
Eectify the globe for the latitude, bring the sun's place in the
ecliptic to the meridian, and set the hour index to XII.; then
turn the globe westward until the index points to the given
hour, and the constellations would then have the same appearance to an eye situated at the center of the globe, as they have
at that moment in the sky.
Ex. Required the aspect of the stars at New Haven, Lat.
41~ 18', at 10 o'clock, on the evening of December 5th.
77. 2Tofind the altitude and cazimuth of anry star: Rectify
the globe for the latitude and the sun's place, and let the quadrant of altitude be screwed to the zenith, and be made to pass
through the star. The arc on the quadrant, from the horizon
to the star, will denote its altitude, and the are of the horizon
from the meridian to the quadrant, will be its azimuth.
Ex. What are the altitude and azimuth of Sirius (the brightest of the fixed stars) on the 25th of December at 10 o'clock
in the evening, in Lat. 410?
7. To fCnd the angular distance of two stars from each
other: Apply the zero mark of the quadrant of altitude to one
of the stars, and the point of the quadrant which falls on the
other star, will show the angular distance between the two.
Ex. What is the distance between the two largest stars of
the Great B3ear?*
79. To find the sutn's meridian altitude, the latitude and day
of the mont/h beinqg given: Having rectified the globe for the
latitude (Art. 66), bring the sun's place in the ecliptic to the
meridian, and count the number of degrees and minutes between that point of the meridian and the zenith. The complement of this arc will be the sun's meridian altitude.
Ex. What is the sun's meridian altitude at noon on the 1st
of August, in Lat. 41~ 18'?
- These two stars are sometimes called "the Pointers," from the line which
passes through them being always nearly in the direction of the north star. The
angular distance between them is about 5~, and may be learned as a standard
for reference in estimating, by the eye, the distance between any two points on
the celestial vault.