diff --git a/Dockerfile b/Dockerfile
index 795026ffe2874473f71de2c0415292b23e403c7c..b2dadfeb6039f839d21aa9f3a82744965728ea29 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -185,6 +185,7 @@ FROM ubuntu:20.04 as runner
 RUN mkdir /src
 COPY --from=builder /usr/local /usr/local
 RUN chmod +rx /usr/local/bin/*
+COPY --from=builder /src/wsclean /opt/
 
 SHELL ["/bin/bash", "-c"]
 
diff --git a/imcal.py b/imcal.py
index f3eb16479ee7363f6f0bacebcc44236a55bc823f..2ceb05c7c45d10a8882321f17899696ba2bd4432 100755
--- a/imcal.py
+++ b/imcal.py
@@ -540,7 +540,7 @@ def main(msin, steps='all', outbase=None, cfgfile='imcal.yml', force=False):
             logging.info('mask step: Image exists, use --f to overwrite...')
         else:
             threshold = img_max/cfg['clean0']['max_over_thresh']
-            threshold = max(threshold, 0.001)
+            threshold = max(threshold, 0.0001)
             wsclean(dical0, outname=img0, automask=None, save_source_list=False, multifreq=False, mgain=None,
                     kwstring=f'-threshold {threshold}')
             create_mask(img0 +'-image.fits', img0 +'-residual.fits', clipval=10, outname=mask0, )