Relative Position of Planets (Chris Kipp)

Research Question

What path do the planets follow as viewed from the Earth?

My hypothesis is that each individual planet will inscribe a circular path across our field of vision.

Standards

HS-ESS1-4. Use mathematical or computational representations to predict the motion of orbiting objects in the solar system. [Clarification Statement: Emphasis is on Newtonian gravitational laws governing orbital motions, which apply to human-made satellites as well as planets and moons.] [Assessment Boundary : Mathematical representations for the gravitational attraction of bodies and Kepler’s Laws of orbital motions should not deal with more than two bodies, nor involve calculus.]

Experimental Design

Students will use an app with a star chart on it (SkyView, for example) to record the positions of the planets each day for a month. Several different star chart apps can be compared for accuracy. The positions must be recorded at the same time each day using both the Right Ascension (RA) and Declination (Dec). These measurements are sometimes referred to as altitude and azimuth. Students will then graph their findings using RA and Dec as their x and y coordinates.

Independent Variable

The independent variable is position. Students must measure the position of the planets at the same time each day.

Dependent Variable

The dependent variable is which planet is being measured and which star chart app is being used. Each planet has its own orbit which will affect the pattern of motion.

Series

Students will be comparing the positions of 9 different planets, the sun, and the moon over a period of 30 days.

Constants and Controls

The time of day will be held constant.

The control will be which star chart app is being used to measure the position of the planet.

Materials

Cell Phone

Sextant

Apps - Star Map 3D, Skyview, Sky Safari 4, Stargaze 3D

Procedures

1. Download one or more apps from the materials list.

2. Every day at the same time, find the planet Mercury in your star chart app.

3. Measure the angle between a line drawn towards Mercury and a line parallel to the equator. Record this as the declination.

4. Measure the angle between a line drawn towards Mercury and a line pointing towards the north pole. Record this as the right ascension.

5. Repeat steps 2-4 for all the other planets, the Sun, and Luna.

6. Take these measurements every day for a month.

Sample Data and Graphs

Example Data and Graph (professionally done)

Photos & Video

References

http://www.davidcolarusso.com/astro/#ra