Update: Now hosted online using Streamlit. Visit: https://pysolar.streamlit.app/

pysolar

• A simple real-time solar system viewer written 100% in Python
• Uses the Skyfield library to pull data from JPL's Development Ephemeris series de440s.bsp file, which includes data from 1849 to 2150
• Displays the system in a scrollable matplotlib window

Usage

• Locally:
  • Download the packages from requirements.txt
  • Open the main.py file in any IDE of your choice with python 1.12 or lower, Skyfield does not support Python 1.13 as of December 2024, and add the following line at the end:

  • plt.show()

  • Run the program to download the required files
  • Once the de400s.bsp file is downloaded, a matplotlib window will open
  • Use your mouse to scroll in and out to see the planets

Understanding the math

Skyfield returns the astronomical positions of the planets as 3D space, (x,y,z), points. The get_position function turns this 3D point into a 2D point by calculating the radius by using the distance formula:

$$\sqrt{\left(x_{2}-x_{1}\right)^{2}+\left(y_{2}-y_{1}\right)^{2}+\left(z_{2}-z_{1}\right)^{2}}$$

and using this radius to scale points x and y on a unit circle with radius of 1. These points can now be placed on a 2D graph and accurately represent the distance between the Sun and the planet.