Surveying Coordinate Systems: Astronomical Coordinate SystemsWhich astronomical coordinates are constantly changing and can readily be measured by a theodolite?
A. right ascension and declination
B. hour angle and declination
C. hour angle and parallactic angle
D. altitude and azimuth
The altitude and azimuth of a celestial body can be measured with respect to the observer's horizon and astronomic north. An instrument such as a theodolite can be successfully oriented to these references with relative ease. The references of the other astronomic coordinates include the First Point of Aries and the celestial equator, among others. It would be considerably more difficult to orient a theodolite to such references.
The answer is D.
This is problem 2 (4-1) from the NEW third edition of “Surveying Solved Problems for the FS and PS Exams” by Jan Van Sickle, PLS (formerly "1001 Solved Surveying Fundamentals Problems"). Reprinted with permission from “Surveying Solved Problems for the FS and PS Exams” by Jan Van Sickle, PLS (2008 Professional Publications Inc.). For details on this and other FLS exam-prep books, call 800/426-1178 or visit www.ppi2pass.com