To verify the reliability of the Survey of some map, we decided to test the angular distances between monuments using a theodolite. a tall multi-storied building was selected as the base of the theodolite readings. The roof offers a good view of all the main monuments.
The theodolite was calibrated and aligned to magnetic north (MN) with a compass and positioned on the south-east corner of the building. Readings were taken in clockwise order from MN, starting with site no. 1. The angular difference between a) two monuments and b) the gross offset from MN was measured and recorded. Due to obstruction by a water tank of the field of view between angles 240° and 350° along the Western horizon, the theodolite was repositioned on the NW corner of the building, reset and re-calibrated with the standard reference and the NS baseline. Due to these adjustments, both theodolite positions can be taken as one, called TP. Interestingly, no monuments were found in line with magnetic north or south, such that the north-south is not emphasised. In contrast, the east-west line is prominently represented in both the terrestrial and celestial schemes. To us, this suggests that the east-west line is the more important basis of calculation in astronomy.
No comments:
Post a Comment