Make a Polar Plot

The Polar Plot Plugin is a powerful tool in KeepTrack.Space that allows you to visualize a satellite’s path across the sky from a specific sensor’s perspective. This 2D representation is particularly useful for understanding satellite passes and planning observations.

What is a Polar Plot?

A polar plot in satellite tracking represents:

• Azimuth: The horizontal angle from North (0-360 degrees), shown as the angle around the circle
• Elevation: The angle above the horizon (0-90 degrees), shown as the distance from the center of the circle
• Time: Represented by the progression of the line on the plot

Note

The center of the plot represents directly overhead (90° elevation), while the outer edge represents the horizon (0° elevation).

Using the Polar Plot Plugin

1. Select a Sensor and Satellite:

   • Choose a sensor using the Sensor List
   • Select a satellite using the search function

2. Open the Polar Plot Plugin:

   • Find the “Polar Plot” icon in the bottom menu (it looks like a polar graph)
   • Click on this icon to open the Polar Plot side menu

3. View the Polar Plot:

   • The plot will automatically generate for the next visible pass of the satellite
   • The line on the plot shows the satellite’s path across the sky
   • Green dot: Start of the pass
   • Red dot: End of the pass

   

4. Interpret the Plot:

   • Follow the line from the green dot to the red dot to see the satellite’s movement
   • The closer to the center, the higher the satellite’s elevation
   • The angle around the circle shows the azimuth (compass direction)

5. Save the Plot (Optional):

   • Click the “Save Image” button below the plot
   • The plot will be saved as a PNG file on your device

Tip

You can use the keyboard shortcut ‘P’ to quickly open or close the Polar Plot plugin.

Example: Creating a Polar Plot for the ISS

Let’s create a polar plot for the International Space Station (ISS) from a specific ground station:

1. Select the Eglin radar sensor (or any other sensor of your choice)
2. Search for and select the ISS (ZARYA) satellite
3. Open the Polar Plot plugin
4. Observe the generated plot showing the next ISS pass
5. Notice the start time and end time of the pass displayed at the top of the plot

Note

If you don’t see a plot, it means the ISS won’t be visible from the selected sensor in the next 48 hours. Try selecting a different sensor or satellite.

Understanding the Plot

• The concentric circles represent elevation angles (15°, 30°, 45°, 60°, 75°, 90°)
• The radial lines represent azimuth angles (0°, 90°, 180°, 270°)
• The satellite’s path is shown as a white line
• The green dot shows where the satellite first becomes visible
• The red dot shows where the satellite disappears from view

Tip

Passes that go closer to the center of the plot (higher elevation) are generally better for observation, as the satellite is higher in the sky and less affected by atmospheric distortion.

Practice Exercise

Try creating polar plots for these scenarios:

1. A GPS satellite from the NESS (GEODSS) sensor in Diego Garcia
2. The Hubble Space Telescope from Fylingdales (SSPAR) in the UK
3. A geostationary satellite (e.g., GOES 16) from Millstone (Haystack) in Massachusetts

Compare the plots and notice how different orbits create different patterns.

By mastering the Polar Plot plugin, you’re gaining a powerful tool for visualizing satellite passes. This can be incredibly useful for planning observations, understanding satellite visibility patterns, and communicating pass information to others.