A configurable astronomy mod that adds a realistic night sky with real life stars, planets and much more. This mod is for those who want to explore the stars while playing minecraft.

Summary of Features

Real life stars and constellations
Galaxies and Nebulae
Planets, moons, asteroids and comets
Shooting Stars and Meteor Showers
Zoomable spyglass, usable as a telescope
Realistic / Seasonal sun and moon positions
Rare astronomical events (Eclipses, and more)
Fully Customizable, custom solar systems supported

Real Life Stars and Constellations

Astrocraft replaces Minecraft's randomly generated stars, with those from real life. Stars come in a range of magnitudes and colors, with bright red stars like Betelgeuse or Arcturus, or more blueish stars like Rigel.

Most stars are so dim, you need a spylass to see them. Zooming in on the Milky Way on a moonless night, you can see thousands of little stars.

As the night progresses, stars revolve around a point in the north sky, marked by Polaris and the Little Dipper.

Orion and Sirius Thousands of stars in the milky way The Crux, and Alpha / Beta Centauri

Galaxies, Clusters and Nebulae

Astrocraft also adds different types of deepsky objects, including:

Open and Globular Clusters, like the Pleiades (M45).
Nebulae like the Orion Nebula (M42), or Ring Nebula (M57)
Galaxies like Andromeda (M31) or Whirlpool (M51)
A subtle Milky Way skybox

For these objects, you need dark skies and high altitude to see well.

Lagoon Nebula Pleiades Cluster Andromeda Galaxy

Shooting Stars and Meteor Showers

Occasionally, you can see streaks of light across the sky. Most meteors belong to a meteor shower, where they radiate from a specific point in the sky. The perseids for example, occur in summer, and radiate from around Perseus or Cassiopeia. Some meteor showers can produce Meteor Storms.

Zoomable Spyglass

Use your mouse's scroll wheel, to zoom in or out, up to 500x magnification. The spyglass works like a telescope, it lets you see objects that are otherwise too dim.

It works best at high altitudes such as on a mountain top, and when the sky is fully dark, not lit by the moon.

Planets and the Solar System

Astrocraft by default, adds every planet, along with many other solar system objects. Planets appear similar to bright stars, but often vividly colored to stand out. Unlike stars, these objects move as the days go by, in realistic keplerian orbits. Positions of these planets in the sky are calculated from their orbital parameters (fully configurable), while also taking into account earth's own orbit. Planets also vary in magnitude (brightness), being brightest at opposition.

Zooming in to a planet, it starts to looks less like a star, and more like the vanilla MC moon. Planets have different textures, Jupiter having bands, Venus being mostly featureless. Inferior planets (Venus and Mercury), also show phases like the moon, based on the direction of the sun.

Timelapse of moons orbiting Jupiter

Some planets are orbited by moons, for example: Jupiter and the Galilean moons. Moons often have short orbital periods, meaning you can see them move over a single night.

Four planets forming a straight line. From left to right: Venus, Mars, Jupiter and Saturn.

Below is a table of the major planets (except Earth), with descriptions of their ingame appearances:

Planet	Brightness	In-game Color	Notes
Mercury	Dim - Bright	White	Always within ~25° of the sun
Venus	Very Bright	White	Always within 45° of the sun, very bright
Mars	Dim - Bright	Red	Bright when in opposition, otherwise dim
Jupiter	Bright	Yellow	Four bright moons visible using a spyglass
Saturn	Dim	Green	Has rings that are visible with enough zoom
Uranus	Very Dim	Cyan	Usually requires a spyglass to view
Neptune	Very Dim	Blue	Difficult to view, even with a spyglass
Pluto	Very Dim	Pink Gray	Like a very dim asteroid, binary with Charon

There are also over 100 asteroids (or dwarf planets), usually orbiting the sun around the asteroid belt. These appear like dim stars, usually requiring a spyglass to see. Subsequent observations may show them slowly moving through the star background.

Comets, which have visible tails and sometimes become very bright as they approach the sun. They have high eccentricity orbits.

Realistic / Seasonal Sun and Moon

Throughout the year, the sun moves relative to the stars, traveling through the zodiac. This determines which stars can be seen at a given time.

Unlike in vanilla minecraft, where the sun, moon and stars all pass overhead, they will now be tilted by the latitude set in the configuration (30°N by default). Additionally, the sun's angle also changes seasonally throughout the year. This causes the day and night to change in length, longer days in summer, longer nights in winter. Setting latitude to 90° or -90° in the configuration will simulate polar day / night.

If you have either serene seasons or fabric seasons installed, Astrocraft automatically syncs to their season cycles.

The Moon

This mod adds moonlight, which lights up the night during a full moon, however may outshine certain objects in the sky. At a new moon, or when the moon is down, the night can be very dark, but it is best for astronomy.

The vanilla MC moon, regardless of phase, is permanently fixed opposite the sun. In Astrocraft, the moon moves independently of the sun. As a result, it is often still up during the day.

Eclipses

A rare astronomical event, the Lunar Eclipse, occurs when a full moon coincides with the moon crossing the ecliptic. A shadow engulfs the moon and turns it red and dark, dimming moonlight for only a few minutes.

During a new moon, the moon can partially or fully cover the sun, completely blocking out the sunlight. This causes the sky to go dark and stars to come out, just like the night. Other astronomical objects, such as Mercury and Venus can also eclipse the sun, they look like small sunspots.

Both the sun and moon up during daytime

A Lunar Eclipse

Customization

If you have mod menu installed you can open the configuration menu, otherwise edit the config file at: "config/astrocraft.json".

Here you can toggle stars or planets off, disable star color, add your own stars and much more. The main option affecting performance is "Magnitude Limit", reduce this if you need to.

Multiplayer Compatibility

Other players on multiplayer worlds with Astrocraft installed will see the same stars and planets as you. However, this won't be the case if you change certain settings, such as "year length" or planets' orbits. Keep this in mind, if you are viewing the night sky with friends.

Constellations

Astrocraft can help you see constellations in the stars by drawing them in the sky. Enable the "Show Constellations" option under the "Overlays" category. It will now show you which stars make up each constellation.

Planets

In the "Planet" category of the menu, you will find a list of all the planets added by the mod. Here you can edit the appearance and orbit of any planet, including earth. Each planet has a list of moons, these can be edited the same way as any planet. You can also add new planets and moons in the config.

Earth is not the only planet you can observe the solar system from, Set "Observing Location" to any planet, moon, asteroid, or even nearby stars. This affects the position of the stars and other planets in the sky. It also allows you to get a close up view of nearby celestial bodies (like Jupiter from Europa).

Config Menu

Compatibility

BadOptimizations: This can be fixed by setting "enable_sky_angle_caching_in_worldrenderer" to "false" in the BadOptimizations config file at "config/badoptimizations.txt".
AdditionZ: Disable "North Star".
Shaders may have visual issues
fabricSkyboxes

Use Sinytra Connector if you want to use with forge or neoforge.

If the mod breaks after updating, try resetting everything in the config, or delete the config file. Don't report shader issues.

Astrocraft: Realistic Night Skies