To solve this problem, they don't bother measuring the base angles at all. This angle differs from 90 degrees by only 0.0044 degrees which equals 16 seconds of arc (there are 60 minutes or arc/degree x 60 seconds of arc/minute of arc = 3600 seconds of arc per degree!) This would be a very difficult angle to measure even with very expensive modern surveying equipment!Īstronomers run into this problem all the time. For example, if the object is 10 miles away, and your baseline is only 5 feet long, the two base angles would have a measure of 89.9946 degrees. This could easily happen if the object were so far away that your instrument could not accurately discern that these angles were different than 90 degrees. Suppose it was hard for you to measure the two base angles in the triangulation method. Teacher Note: At this point, have the students measure the distance to some remote object in the school yard by using the above triangulation method. By knowing the base distance A to B, and the baseline distance S, the distance to the peak can be worked out with a simple scaled drawing or with trigonometry. The base angles at A and B can be measured with an instrument called a theodolite. In ordinary land surveying, imagine a distant mountain peak and two observers are located at 'A' and 'B' separated by a few miles (the length 'S'). They use a method called 'triangulation'. Surveyors and geologists encounter this kind of problem all the time, and over the course of centuries, they have found a simple way to sole this problem. ![]() ![]() Teacher Note: Have the class suggest ways that they could measure this distance. Could you come up with a way to make this measurement safely? Suppose you were trying to measure the width of a canyon from your side to the distant canyon wall. Teacher Note: To see the following activity completely worked out for the Transit of Mercury on May 7, 2003, please look at the following page: Calculating the Astronomical Unit During a Transit of Mercury Using Satellite Data.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |