diff --git a/pypeit/scripts/sensfunc.py b/pypeit/scripts/sensfunc.py
index d17ee5cb0d..75b7dd77c1 100644
--- a/pypeit/scripts/sensfunc.py
+++ b/pypeit/scripts/sensfunc.py
@@ -120,21 +120,21 @@ def main(args):
                        "              multi_spec_det = 3,7\n"
                        "\n")
 
-        # Determine the spectrograph
-        hdul = io.fits_open(args.spec1dfile)
-        spectrograph = load_spectrograph(hdul[0].header['PYP_SPEC'])
-        spectrograph_config_par = spectrograph.config_specific_par(hdul)
-
-        # Construct a primary FITS header that includes the spectrograph's
-        #   config keys for inclusion in the output sensfunc file
-        primary_hdr = io.initialize_header()
-        add_keys = (
-            ['PYP_SPEC', 'DATE-OBS', 'TELESCOP', 'INSTRUME', 'DETECTOR']
-            + spectrograph.configuration_keys() + spectrograph.raw_header_cards()
-        )
-        for key in add_keys:
-            if key.upper() in hdul[0].header.keys():
-                primary_hdr[key.upper()] = hdul[0].header[key.upper()]
+        # Determine the spectrograph and generate the primary FITS header
+        with io.fits_open(args.spec1dfile) as hdul:
+            spectrograph = load_spectrograph(hdul[0].header['PYP_SPEC'])
+            spectrograph_config_par = spectrograph.config_specific_par(hdul)
+
+            # Construct a primary FITS header that includes the spectrograph's
+            #   config keys for inclusion in the output sensfunc file
+            primary_hdr = io.initialize_header()
+            add_keys = (
+                ['PYP_SPEC', 'DATE-OBS', 'TELESCOP', 'INSTRUME', 'DETECTOR']
+                + spectrograph.configuration_keys() + spectrograph.raw_header_cards()
+            )
+            for key in add_keys:
+                if key.upper() in hdul[0].header.keys():
+                    primary_hdr[key.upper()] = hdul[0].header[key.upper()]
 
         # If the .sens file was passed in read it and overwrite default parameters
 
diff --git a/pypeit/tests/test_runpypeit.py b/pypeit/tests/test_runpypeit.py
index 7640591405..eb1c157868 100644
--- a/pypeit/tests/test_runpypeit.py
+++ b/pypeit/tests/test_runpypeit.py
@@ -75,7 +75,6 @@ def test_run_pypeit():
     sf = sensfunc.SensFunc.from_file(str(sens_file))
     assert len(sf.wave) > 0
     assert len(sf.zeropoint) > 0
-    sf = None
 
     # Flux calibrate
     with open(outdir / "fluxfile", "w") as f:
@@ -113,7 +112,6 @@ def test_run_pypeit():
     assert len(specObjs[0].BOX_FLAM[mask]) != 0
     assert len(specObjs[0].BOX_FLAM_IVAR[mask]) != 0
     assert len(specObjs[0].BOX_FLAM_SIG[mask]) != 0
-    specObjs = None
 
     # Clean-up
     shutil.rmtree(outdir)