CurseForge · Minecraft mod
Caelum
Realistic stars and Keplerian orbital mechanics of the Sun, Earth, Moon and the planets. Now with eclipses and stuff
Quick answer
Which Caelum release should I use?
caelum-3.0.0.6+1.21.1.jar targets 1.21.1 with NeoForge. The project page does not say whether this file belongs on the client, dedicated server, or both. No extra mods listed for this file.
Where it goes
Is Caelum required on the client, server, or both?
The project page does not say whether this file belongs on the client, dedicated server, or both.
The source does not explicitly classify this release as client-only or server-only.
What else does caelum-3.0.0.6+1.21.1.jar need?
caelum-3.0.0.6+1.21.1.jar. Change the file and its required mods may change too.
This file does not list any required mods. Do not add a library just because a different file uses it.
This file does not list any required or optional mods.
Before you install it
Add Caelum without breaking your instance.
Built for caelum-3.0.0.6+1.21.1.jar. Pick another file and the loader, install side or required mods may change.
- 01
Stick to this file
Use caelum-3.0.0.6+1.21.1.jar. It targets 1.21.1 with NeoForge; another release may have different loader, side or dependency requirements.
- 02
Bring the mods it needs
This file does not list any required mods. Do not add a library just because a different file uses it.
- 03
Put it on the correct side
The project page does not say whether this file belongs on the client, dedicated server, or both.
- 04
Pick the file you checked
Use the “Get this file” button beside caelum-3.0.0.6+1.21.1.jar. It opens that exact file at the source.
About this project
What does Caelum add?
Caelum

Caelum is a Minecraft mod, that aims to make the Minecraft sky more realistic by calculating the positions of the major solar system objects (namely the Earth and Moon) based on their Keplerian orbital elements for the given date.
The mod allows you to:
- choose whether to use the Vanilla or custom stars (or whether to render stars at all)
- add or even replace the custom stars using resource packs
- add and edit celestial objects like moons and planets
- enable/disable star color (does not apply to Vanilla stars)
- change star size (does not apply to Vanilla stars)
- change the speed of passage of time (i.e. how long the day and night are)
- have a different length of the day depending on your latitude (the Z coordinate) - resulting in polar days and nights near polar regions.
- Experience solar and lunar eclipses and planet transits
The positions of the planets correspond to their positions IRL within some tolerance, thus resulting in solar/lunar eclipses on the same* dates as they would IRL.
Keep in mind that the shader support is partial at best. While the positions of the Sun and the Moon and their shadows should be right for a large portion of shaders, stuff like custom stars or planets are almost certainly not going to work, as the shaders do their own sky rendering.
*Vanilla Minecraft Sun and Moon are several times larger than they are IRL, resulting in more eclipses. Their size can be made more realistic in the config.
Project description from CurseForge.
Pick your setup
Caelum by Minecraft version and loader
Choose the version and loader you play, then open the matching release.
1.20.1
2 loader builds1.18.2
1 loader build1.18.1
1 loader buildCheck the dependencies, then try the file in a copied instance before changing a world you care about.
Recent files
Caelum versions and loaders
caelum-3.0.0.6+1.21.1.jar
22 Sept 2026
caelum-3.0.0.5+1.21.1.jar
14 Sept 2026
caelum-3.0.0.4+1.21.1.jar
10 Sept 2026
caelum-3.0.0.3+1.21.1.jar
9 Sept 2026
caelum-3.0.0.1+1.21.1.jar
8 Sept 2026
caelum-3.0.0.0+1.21.1.jar
8 Sept 2026
caelum-2.0.0.0+1.21.1.jar
30 Jul 2026
caelum-1.20.1-2.0.0.0.jar
31 Jul 2023
caeulum-1.18.2-1.0.1.0.jar
11 Mar 2022
caeulum-1.0.0.0.jar
12 Dec 2021
Looking for an older file? The official CurseForge project page is in Resources.