Latitude and Longitude An Overview

Changing Perspectives People normally see the world from the perspective of standing on the surface of the earth To understand latitude and longitude, you are required to change your perspective or frame of reference

Changing Perspectives Cont’d You must now see the earth from a position in space looking down at the world, just like an astronaut! The same applies to the sun, which is a sphere just like earth. This can be challenging, but it can be done!

The Equator Latitude is measured above and below the Equator in degrees. e

Lines of Latitude These parallel lines on the globe are lines of latitude.

Latitude Latitude angles are measured from the centre of the earth (vertex of the angle)

Prime Meridian The Prime Meridian passes through Greenwich, England

Prime Meridian Marker A marker showing the actual location of the Prime Meridian in Greenwich, England 6/normal/PrimeMeridian.jpg

Lines of Longitude

Longitude Angles Longitude is measured in degrees east or west of the Prime Meridian Angles are measured from the centre of the earth (vertex of angle) east or west of the Prime Meridian

Longitude Top down view of world Longitude is measured in degrees east or west of the Prime Meridian

Latitude and Longitude combined Latitude and longitude measurements are based on angle measurements as shown in this diagram and previous two diagrams

What is the Lat and Long of this point?

How to Measure Sunspot Movement with Angles Problem: We need to measure the change in longitude of the sunspots on a 2-D image of the sun Solution: The next few slides show you how to do this.

How to Measure Sunspot Movement with Angles 1 st – draw a line straight up to the edge of the sun and mark the point X NASA/SOHO

How to Measure Sunspot Movement with Angles Cont’d 2 nd – on a more recent image, repeat step 1 X X NASA/SOHO

How to Measure Sunspot Movement with Angles Cont’d 3 rd – locate the centre of the sun and draw an equator The cross lines found the centre X X NASA/SOHO

How to Measure Sunspot Movement with Angles Cont’d 4 th – draw lines from the centre to the marked points and measure the angle with a protractor X X NASA/SOHO

How to Measure Sunspot Movement with Angles Cont’d The angle measured represents the change in longitude of the sunspot X X NASA/SOHO