diff --git a/python/lsst/obs/lsst/script/write_comcam_manual_defects.py b/python/lsst/obs/lsst/script/write_comcam_manual_defects.py
index a2899b64..e6cf9bf3 100644
--- a/python/lsst/obs/lsst/script/write_comcam_manual_defects.py
+++ b/python/lsst/obs/lsst/script/write_comcam_manual_defects.py
@@ -31,7 +31,7 @@
 
 data_root = lsst.utils.getPackageDir("obs_lsst_data")
 
-valid_start = "2024-10-20T00:00:00"
+valid_start = "1970-01-01T00:00:00"
 valid_date = dateutil.parser.parse(valid_start)
 datestr = "".join(re.split(r"[:-]", valid_date.isoformat()))