Currently playing on Valhelsia 3 modpack (Valhelsia 3.1.1) on a server which is using Astral 1.13.8 on MC 1.16.4. The base of the Celestial Gateway has what looks like an unnamed constellation on the outside base, but even looking at that block of marble with my cursor causes a crash to desktop. This sometimes leads to crashes on login unless I very quickly look up upon logging into the server before chunks render. Crashes both with or without optifine, my suspect is on Hwyla, but I could be wrong. Filename for Hwyla in Valhelsia 3 is "Hwyla-forge-1.10.11-B78_1.16.2"

The constellation in question

Crash log (With OF)
crash-2020-12-24_15.56.02-client.txt

EDIT: Clarified Valhelsia modpack version