Exterior Planets Mars, Jupiter, Saturn

• Opposition: sun, earth, planet all in straight line with each other.

• Quadrature: sun to earth to planet forms right angle.

• By measuring the time it takes to go from opposition to quadrature, we can calcuate α for the earth and ß for the planet.

• α - ß gives us one angle of the right triangle at quadrature.

• d = 1/cos( α- ß)