a) Use the example of the altitude of Polaris and its relationship to latitudes

Question

a) Use the example of the altitude of Polaris and its relationship to latitudes on the Earth to show how the accuracy in measuring the altitude of a star translates directly into the accuracy in determining your location on the Earth. b) Which geographical coordinate, latitude or longtitude or both, can you determine in this way? c) What if you were a Polynesian "wayfinder" (navigator) and did not use a compass or any other very accurate measuring device but you used measurements of a star's altitude made using your hand and fingers to determine when you were on the correct latitude to make "land fall". For example, to sail to Hawaii from the south, the wayfinder would watch the Southern Cross (when it is "upright" and so crossing the meridian) descend as she/he sailed north until the bottom star is 6 degrees above the horizon. Calcuate the accuracy in latitude that this traditional observing technique yields?

d) Is this accuracy good enough for the wayfinder to find Hawaii?

Explanation / Answer

a. The altitude of Polaris is 90° at North Pole whereas it is 0° at equator. So by measuring the angle between our location and Polaris we can exactly measure our latitude. We measure our location by measuring the angle between a star and our location. By taking no of such measurements with 3 to 5 stars we can calculate our location on the earth as the intersection of lines. So if we measure precise angle we can calculate our location accurately.

b.The altitude measurements can be used to measure our latitude only. Though there are methods to determine longitude but measurement of altitude can not provide the longitude.

C. Using the traditional methids the ppossible accuracy is 1 degree

1°= 110 km

d. thi ths accuracy is not enough to find Hawaii

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.