diff --git a/csst_ifs_sim/csst_ifs_sim.py b/csst_ifs_sim/csst_ifs_sim.py
index 0203678a26f341fa076f0298bfd3e10399531dd7..2207ebedfe90952066ef1b2e157c6f130331c481 100644
--- a/csst_ifs_sim/csst_ifs_sim.py
+++ b/csst_ifs_sim/csst_ifs_sim.py
@@ -124,7 +124,7 @@ conf.auto_max_age = None
 from scipy.integrate import simps
 import pandas as pd
 from datetime import datetime, timedelta
-import julian
+###import julian
 from astropy.coordinates import get_sun
 from astropy.time import Time
 from astropy import units as u