Celestial Unofficial 2.0 Fix

Fixed crash with forge version of Celestial 2.0

by
459 Downloads
neoforge
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About this Mod

This mod fixes critical crashes in Celestial 2.0 for NeoForge 1.21, allowing Forge/NeoForge users to enjoy the full sky customization features of Celestial.

What This Fixes
Celestial 2.0 for NeoForge crashes on startup due to incompatible mixin refmap mappings. The original mod's refmap uses Fabric/Yarn intermediary mappings (field_20898, field_21327, field_21328, etc.), but NeoForge requires Mojang mappings (poseStack, pose, normal, etc.).

Without this fix, you'll encounter:

  • Immediate crashes when launching with Celestial 2.0 on NeoForge
  • Mixin application failures referencing missing field mappings
  • Inability to use Celestial's sky customization features on Forge-based modpacks
  • With this fix, Celestial 2.0 works seamlessly on NeoForge 1.21, enabling:
  • Custom planets and stars in the sky
  • Sky and fog color customization
  • Custom skyboxes and animated skies
  • Resource pack-based configuration (no config files needed)
  • Full compatibility with vanilla and modded dimensions

Technical Details
This fix patches Celestial-common-refmap.json by adding the searge section with correct Mojang mapping names, ensuring mixin transformations apply correctly to NeoForge's obfuscated classes. No gameplay code was modified—only the mapping references needed for NeoForge compatibility.

Compatibility

  • Minecraft Version: 1.21
  • Mod Loader: NeoForge
  • Fixed Version: Celestial 2.0

Installation
Simply add this mod to your mods folder. Remove the original broken celestial_1.21_neoforge-2.0.jar if present.

About This Fork
This is a compatibility patch for Celestial by fishcute. The original author permits reuploads and fixes. This project exists solely to provide NeoForge users with a working version until an official update is released.

Available Versions

Celestial Unofficial 2.0 Fix 2.0release
MC 1.21, 1.21.1, 1.21.2, 1.21.3, 1.21.4, 1.21.5, 1.21.6, 1.21.7, 1.21.8, 1.21.9, 1.21.10, 1.21.11neoforge
February 7, 2026

How to Install Celestial Unofficial 2.0 Fix on Your Server

1

Order Server

Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).

2

Set neoforge Loader

In the panel under "Egg", select the neoforge loader and matching Minecraft version (1.21.11).

3

Install Mod

Open the mod browser in the dashboard and search for "Celestial Unofficial 2.0 Fix". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.

Compatibility

Mod Loaders

neoforge

Minecraft Versions

1.21.11, 1.21.10, 1.21.9 (+9 more)

Server-side

Required

Recommended RAM

4 GB(min. 3 GB)

Frequently Asked Questions

Celestial Unofficial 2.0 Fix server crashes on startup – what to do?

Most common cause: wrong neoforge version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.21.11). You can switch loaders with one click in the panel.

Is Celestial Unofficial 2.0 Fix compatible with neoforge?

Celestial Unofficial 2.0 Fix officially supports neoforge for Minecraft 1.21.11, 1.21.10, 1.21.9. The Mado dashboard automatically detects incompatible loader combinations.

Server lagging with Celestial Unofficial 2.0 Fix – how to optimize performance?

Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Celestial Unofficial 2.0 Fix consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.

Rent Modded Server

Install Celestial Unofficial 2.0 Fix with just one click on your server.

Recommended RAM
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Details

License
MIT License
Server-side
Required

Supported Versions

1.21.111.21.101.21.91.21.81.21.71.21.61.21.51.21.41.21.31.21.2+2 more