diff --git a/Project.toml b/Project.toml
index f082087..6ab4e3e 100644
--- a/Project.toml
+++ b/Project.toml
@@ -16,6 +16,7 @@ SpecialFunctions = "276daf66-3868-5448-9aa4-cd146d93841b"
 VLBISkyModels = "d6343c73-7174-4e0f-bb64-562643efbeca"
 
 [compat]
+Bessels = "0.2"
 ComradeBase = "0.5"
 DocStringExtensions = "0.9"
 EHTUtils = "0.1"