Create a Backyard Compass
The ORIGINAL Classical Astronomy Backyard Compass! Often Imitated, Never Duplicated!
These are the instructions for the ORIGINAL Classical Astronomy Backyard Compass, first published in our Signs & Seasons curriculum in 2007 and in the companion Field Journal in 2008. The Backyard Compass has proven to be a very useful and popular activity... so much so that it has been bootlegged by many (who didn't even bother to give it their own name!) A Backyard Compass is an indispensible tool for learning the cycles of the Sun, Moon, stars and planets, especially for the purpose of natural timekeeping and navigation from these celestial bodies. Let's get started!
Create a Backyard Compass
Necessary materials:
Some sticks, a tape measure, and five paving stones from a garden supply center.
This is a very important project that will be used throughout the field activities. You will make a compass that is big enough to stand on, as shown in the book. This will help you find direction
and learn to orient yourself as you learn the constellations and signs of the seasons.
The first thing you need to do is find “high noon,” when the Sun is highest in the sky and the shadows are the shortest. As Pliny the Elder instructed in A.D. 50:
After observing the quarter in which the Sun rises on any given day, at the sixth hour of the day (i.e. at Noon) take your position in such a manner as to have the point of the Sun’s rising on your left; you will then have the south directly facing you, and the north at your back: a line drawn through a field in this direction is called the “cardinal” line... It will be the sixth hour of the day, at the moment when the shadow straight before him is the shortest. Through the middle of this shadow, taken lengthwise, a furrow must be traced in the ground with a hoe, or else a line drawn with ashes, some twenty feet in length.
So here’s what to do:
* Pick a site in your backyard away from the house and other buildings, with a wide open view in as many directions as possible. (Get your parent’s permission before beginning!)
* Place a stick in the ground about one foot long. Be sure the stick is placed very straight in the ground.
* On a sunny day, observe the shadows from between about 11:00 AM and 2:00 PM (since high noon can occur at very different times depending on the season and your location.)
* Every 20-30 minutes, place a short twig into the ground at the end of the stick’s shadow.
* After the time is up, use a ruler or tape measure to find the distance between each twig and the stick. The shortest distance is your
cardinal line that runs from north to south!

* Carefully extend your cardinal 1ine 10 feet (3 meters) to the north and to the south from your stick. Place paving stones at each point. These are the north and south points of your compass.
* Remove the stick and place a paving stone in its place. This is your central standing stone.
* From your standing stone, measure a line perpendicular to your cardinal line, another 10 feet (3 meters) on either side. Check carefully to make sure your lines are even. Place paving stones at these ends. These are the east and west points of your compass.

* Recheck your compass over the next two or three days to make sure that the shadows really are shortest in the direction of your cardinal line.
* (OPTIONAL -- Add four more marker stones between the cardinal stones to indicate NE, NW, SE and SW.)
* When your compass is accurate, you can now stand on your standing stone and look at each direction of the compass, day or night and when it’s cloudy!
* You can write the names of the directions on your compass points -- N-E-W-S – help every member of the family find the compass points. Also, you can dig out under your stones to set them in the earth, to make sure the lawn mower won’t hit them.
* If space does not permit, you can create a temporary backyard compass on a driveway or other pavement surface using sidewalk chalk.
For many activities and to learn the cycles of the Sun, Moon, stars and planets, order your copies of Signs & Seasons and the Field Journal .
Make this the year your family studies astronomy!
Please drop us an email to let us know how your Backyard Compass turned out, or if you have any questions! Thanks, jay





