--- a/debian/patches/reproducible-build.patch	1970-01-01 01:00:00.000000000 +0100
--- b/debian/patches/reproducible-build.patch	2020-07-13 12:30:17.783317854 +0100
@@ -0,0 +1,26 @@
+Description: Make the build reproducible
+Author: Chris Lamb <lamby@debian.org>
+Last-Update: 2020-07-13
+
+--- pyerfa-1.7.0+ds.orig/docs/conf.py
++++ pyerfa-1.7.0+ds/docs/conf.py
+@@ -27,6 +27,7 @@
+ 
+ from datetime import datetime
+ import sys
++import os, time
+ 
+ from pkg_resources import get_distribution
+ 
+@@ -41,7 +42,10 @@ except ImportError:
+ 
+ project = 'PyERFA'
+ author = 'The PyERFA Developers'
+-copyright = '2011\u2013{0}, {1}'.format(datetime.utcnow().year, author)
++build_date = datetime.utcfromtimestamp(
++    int(os.environ.get('SOURCE_DATE_EPOCH', time.time()))
++)
++copyright = '2011\u2013{0}, {1}'.format(build_date.year, author)
+ 
+ # The version info for the project you're documenting, acts as replacement for
+ # |version| and |release|, also used in various other places throughout the
--- a/debian/patches/series	1970-01-01 01:00:00.000000000 +0100
--- b/debian/patches/series	2020-07-13 12:30:16.695345996 +0100
@@ -0,0 +1 @@
+reproducible-build.patch