Celestia Forums

This topic has come up again on Discord so here's a poll on it. Celestia currently uses the "moon" class for large moons (≥200 km radius) and "minormoon" for all other moons, regardless of what they orbit. This is based on Celestia Origin & Project Echoes conventions, and was further clarified here on GitHub. However differentiating between "moon" and "minormoon" isn't useful for Mars, which only has minor moons; if only "moon" orbits are enabled the orbits of Phobos and Deimos won't be shown. The same logic applies to moons of asteroids (which do in fact use "moon" in Origin but not Echoes).

I don't have a strong opinion on this.

Relevant old thread linked by pedro_jg, from when the "minormoon" class was first introduced.

In Celestia Origin only moons of asteroids always have the "moon" class, because asteroids cannot have really large objects in their orbits (always less than 400 kilometers in diameter but most often less than 100). This is done for the convenience of the user.

However, classical/dwarf planets have moons of a wide variety of sizes, and here the use of two classes is justified. The absence of large satellites for a particular planet is not an excuse to assign every little thing to a different class.

Phobos and Deimos are small no matter how you look at them (especially when compared with Mars). A similar situation with Hiʻiaka and Namaka. In Celestia Origin, the moons of Mars and Haumea are defined as "minormoon". My vote applies specifically to them, but in general this requires a compromise solution, which I have already described.