Mapping the Solar System from Earth

After this project you will be able to determine the position of any object in the solar system from its position in our sky and vice versa.

Steps

1. Our time is based on position of Sun. Noon is when you are (your meridian is) pointing toward the Sun.

2. You will be facing South to see solar system objects. Earth spins COUNTER-CLOCKWISE so:

• SOUTH will be in same direction as you.
• EAST will be toward the LEFT
• WEST will be toward the RIGHT

3. Place yourself at given time of day. Time based on position of Sun. Earth spins counter-clockwise so:

• 6 PM = sunset is 90 degree spin from noon
• Midnight is directly away from Sun
• 6 AM = sunrise is 90 degree spin from midnight

4. Draw horizon line as straight line below your feet, perpendicular to yourself extending out into space. Put East and West direction on horizon line. (Noon horizons shown below.)

5. Objects in western sky are to the right (west) of the meridian. Setting objects are along the west horizon line.

6. If going from orbit position (orrery) view to ground-sky (horizon) view:

• Meridian is straight ahead (south). Objects you are pointing toward (straight above your head) are in the southern sky.
• Objects left of the meridian line are in the eastern sky. Objects along east horizon line are rising.
• Objects right of the meridian line are in the western sky. Objects along west horizon line are setting.

Here's an example for a view at sunset. Note the meridian is for the SUNSET direction. The Sun is setting in the West.

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