diff --git a/pyproject.toml b/pyproject.toml
index 5fe9f0ae..3b53de52 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -19,7 +19,7 @@ dynamic = ["version"]
 requires-python = ">=3.9"
 dependencies = [
     "aiohttp", # http filesystem support
-    "astropy",
+    "astropy<6.1",
     "fsspec>=2023.10.0", # Used for abstract filesystems
     "healpy",
     "jproperties",