diff --git a/csst_mci_sim/csst_mci_sim.py b/csst_mci_sim/csst_mci_sim.py
index 6885d544d0b0c1d587873459eaf35ee810957309..451939ff19c6057e04e72b10595c4a74619ab1c3 100644
--- a/csst_mci_sim/csst_mci_sim.py
+++ b/csst_mci_sim/csst_mci_sim.py
@@ -345,11 +345,11 @@ class StrayLight(object):
         self.slcdll.ComposeY.argtypes = [ctypes.POINTER(ctypes.c_double), ctypes.POINTER(ctypes.c_double),
                                        ctypes.POINTER(ctypes.c_double)]
         self.slcdll.Init.argtypes=[ctypes.c_char_p,ctypes.c_char_p,ctypes.c_char_p,ctypes.c_char_p]
-        self.deFn = "../MCI_inputData/refs/DE405"
-        self.PSTFn = "../MCI_inputData/refs/PST"
-        self.RFn = "../MCI_inputData/refs/R"
-        self.ZolFn = "../MCI_inputData/refs/Zodiacal"
-        self.brightStarTabFn = "../MCI_inputData/refs/BrightGaia_with_csst_mag"
+        self.deFn = self.path+"MCI_inputData/refs/DE405"
+        self.PSTFn = self.path+"MCI_inputData/refs/PST"
+        self.RFn = self.path++"MCI_inputData/refs/R"
+        self.ZolFn =self.path++ "MCI_inputData/refs/Zodiacal"
+        self.brightStarTabFn = self.path+"MCI_inputData/refs/BrightGaia_with_csst_mag"
 
         self.slcdll.Init(str.encode(self.deFn),str.encode(self.PSTFn),str.encode(self.RFn),str.encode(self.ZolFn))