diff --git a/modules/util/viirs.py b/modules/util/viirs.py
index 7d130db4af1de9f6ee31f9e42d714be0483e63c9..4ae771a4c00d6488c3da4bdbfdb7d52916357c9a 100644
--- a/modules/util/viirs.py
+++ b/modules/util/viirs.py
@@ -16,9 +16,10 @@ def run_all(directory):
     img_tiles = []
 
     for idx, mfile in enumerate(mod_files):
-        w_o_ext, ext = os.path.splitext(mfile)
-        ifile = w_o_ext+'uwssec'+ext
-        run(mfile, ifile, mod_tiles, img_tiles)
+        if idx % 2 == 0:
+            w_o_ext, ext = os.path.splitext(mfile)
+            ifile = w_o_ext+'uwssec'+ext
+            run(mfile, ifile, mod_tiles, img_tiles)
 
     mod_nda = np.stack(mod_tiles)
     img_nda = np.stack(img_tiles)