diff --git a/notebooks/ACS/acs_reduction/requirements.txt b/notebooks/ACS/acs_reduction/requirements.txt
index fdb96373e..e0b429663 100644
--- a/notebooks/ACS/acs_reduction/requirements.txt
+++ b/notebooks/ACS/acs_reduction/requirements.txt
@@ -3,3 +3,4 @@ astroquery>=0.4.6
 stwcs>=1.7.2
 crds>=11.17.0
 matplotlib>=3.7.0
+pyraf