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starward v0.3.0: Planetary Motion

· 2 min read
Oddur Sigurdsson
Oddur Sigurdsson
Creator of astr0

The planets join starward in version 0.3.0. From Mercury's swift orbit to Neptune's distant path, you can now track all eight planets with the same educational transparency that defines starward.

The Planets Module​

Position Calculations​

Get the current position of any planet in multiple coordinate systems:

starward planets position mars
starward planets position jupiter --verbose

With --verbose, you'll see the orbital elements, heliocentric coordinates, and the step-by-step transformation to geocentric positions.

Visual Magnitude​

Know how bright a planet will appear:

starward planets magnitude venus
starward planets magnitude saturn --observer "Home"

Magnitude calculations account for the planet's distance from both the Sun and Earth, plus phase angle effects for the inner planets.

Elongation​

Track a planet's angular distance from the Sun — essential for observation planning:

starward planets elongation mercury
starward planets elongation venus --verbose

Mercury and Venus are best observed at maximum elongation. starward tells you when.

Rise, Set, and Transit​

Plan your observing sessions:

starward planets rise saturn --observer "Home"
starward planets transit jupiter
starward planets set mars

Opposition and Conjunction​

Find the best times to observe:

starward planets opposition mars
starward planets conjunction venus

Opposition is when an outer planet is closest to Earth and visible all night. starward calculates the next occurrence.

Documentation Migration​

This release also marks the migration to Docusaurus for documentation. The new site features:

  • Improved navigation and search
  • Better code examples with syntax highlighting
  • Mobile-friendly responsive design
  • Module-by-module guides

Example Session​

# Set up your location
starward observer add "Backyard" --lat 34.0522 --lon -118.2437 --tz "America/Los_Angeles"

# What planets are visible tonight?
starward planets position jupiter --observer "Backyard"
starward planets rise saturn --observer "Backyard"

# When's the next Mars opposition?
starward planets opposition mars --verbose

Getting Started​

pip install starward

Explore the planets module guide for complete documentation.

What's Next​

Future releases will explore asteroids, comets, and deep-sky object catalogs. The mission remains the same: astronomy calculations that teach while they compute.