Introduction to Earth Rotation Measurements
This free online course on the rotation of the earth, as well as the methods of position fixes, and sextant angles.Publisher: ADU
CertificationView course modules
The introduction to the axis of the earth is a free online course that begins by introducing you to the rotation of the earth, how the development of the gyrocompass can be used for marine navigation, and the directions on the compass card. The course also discusses gyro error, as well as how the magnetic compass can be fitted on ships. The course will also introduce you to the application, significance of position lines and positions, the various methods of plotting positions on a chart, along with the source of errors in position lines and position fixes. How to use the horizontal sextant angles in position fixing on a chart will also be covered in this course. The course will also explain the primary method of position fixing, position accuracy, the celestial fix, along with how navigators can be used to plot a fix consisting of the intersection of two or more distance arcs. The fix by distance races, visual fixes, and how to use the vertical sextant angle (VSA) of a terrestrial charted object to get range and position will be highlighted in the course. Also, you will learn how the position circle can be obtained, and how to use the three-point bearing to obtain a position.
The course then explains how to sail on a true course using a magnetic compass, how a magnetic deviation can be caused, the reasons for using magnetic courses, as well as the concept of the parallel sailing and how to solve the parallel sailing. You will learn how the traverse table can be used by a navigator, and how a traverse table can be used for plane sailings. The course will also analyze the procedure for using the traverse table for plane sailing, along with the procedure that can be used to find course and distance. This course will teach you the distance between two positions, how to use plane trigonometry without any error, formulas that can be used to find course and distance, as well as examples of calculation plane sailing. You will learn how to solve parallel sailing, rhumb line practical approach to navigation, as well as how the magnetic deviation can be used for correcting for both deviation and variation. The course will also cover how the magnetic course can be used to convert a true course into a compass course, and the application of the marine compass.
Furthermore, this course will help you get familiar with how the earth rotates on its own axis, and at the same time how it revolves around the sun in an elliptical orbit. You will also learn how the fixed orientation and the tilt of the axis causes different seasons as the earth orbits around the sun. The course will teach you how the gyrocompass applies the mutual effects of gravity and the earth's rotation. Also, the characteristics of the 'gyroscope and the things that should be observed to use the gyrocompass as a compass on the earth will be explained. You will learn about the thumb rules that are required for the conversion of compass bearings to true bearings and vice versa. The lines of position (LOPs), determining the position by horizontal angles, and how to use a sextant to measure them will be examined in this course. The introduction to the axis of the earth-course will help you improve your knowledge of the important concept in navigating. This free online course will be of great interest to students, researchers, and anyone with an interest in understanding the rotation of the Earth in marine navigation. So, register for this course and start your next learning journey today.Start Course Now
Axis of Rotation
Axis of Rotation - Learning Outcomes
Rotation of the Earth
Lines of Position Fixes
Method of Position Fixing
Vertical and Horizontal Sextant Angles
True Course and Parallel Sailing
Use of Traverse Table
Axis of Rotation - Lesson Summary
Upon the successful completion of this course, you should be able to:
- Describe the earth's axis of rotation, as well as the process of location directions.
- Explain the working of a Magnetic Compass for navigation.
- Explain the significance and application of position lines and positions.
- Outline the various methods of plotting positions on a chart.
- Identify the source of errors in position lines and position fixes and their corrections.
- Describe the use of Horizontal Sextant Angles in position fixing on a chart.
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