Hey Ray: The sun compass

Hey Ray: The Sun Compass

PITTSBURGH (KDKA) - How about some survival science?  

No, we are not going to wrestle bears, but I am going to show you how to find your direction.  If you have ever been lost in an unfamiliar place, knowing directions can be very important. 

To figure out a direction, all you need is our closest star. 

The Sun!

You know the sun, the S-U-N.  Ray Petelin

There are three main latitude lines on a map: the Equator, the Tropic Of Cancer, and the Tropic Of Capricorn. 

These lines of latitude are important to understanding the Sun's position. 

The three main points of latitude on a map.  Ray Petelin

Throughout the year, the Sun will only be directly overhead locations between the Tropic of Capricorn and the Tropic of Cancer. Those locations are 23.5° South and 23.5° North respectively.

The points of the main lines of latitude.  Ray Petelin

Since all three of those lines are well south of us, and we are in the Northern Hemisphere, the Sun will always travel East to West in our southern sky. This gives us the first bit of knowledge to make a compass using the Sun.  

Since the Sun takes its daily east-to-west path through our southern sky, that means the shadows it casts will be pointing north-ish. 

This information is useful in narrowing down our directions. 

North...ish... Ray Petelin

Next, we will need a straight stick or pole.  We will use this to track the Sun's path, so we can finish our compass. 

Put the stick on the ground and mark the end of the shadow. For my experiment, I am using the flat edges of these rocks for markers.  You can put smaller sticks in the ground if you want as well. 

Again, mark the end of the shadow. 

This is me, marking a shadow! Ray Petelin

You then wait 15 minutes for the Sun to move, then mark the end of the next shadow. 

15 minutes later, marking the end of the shadow.  Ray Petelin

Do that two more times and you will have a line of markers.

Pointing north...ish Ray Petelin

The rock on your left is your western coordinate. The rock on the right is the eastern coordinate. If you put your feet on the two rocks in the middle and face the direction the shadow was pointing, you will be looking northward! 

The Sun Compass! Ray Petelin

This is not going to be perfectly accurate, but it will get you going in the right direction.

Pretty close!  Ray Petelin

Obviously, this won't work when it is cloudy!

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