diff --git a/Pipfile b/Pipfile
index 89e84bb..a28f981 100644
--- a/Pipfile
+++ b/Pipfile
@@ -16,7 +16,7 @@ tabulate = "*"
 numpy = ">=1.17.0,<2.0.0"
 termcolor = "*"
 latex = "*"
-dateutil = ">=2.8.1"
+dateutil = "*"
 
 [requires]
 python_version = "3"
diff --git a/kosmorrolib/main.py b/kosmorrolib/main.py
index 41c7b38..26e2b97 100644
--- a/kosmorrolib/main.py
+++ b/kosmorrolib/main.py
@@ -109,7 +109,7 @@ def get_date(date_arg: str) -> date:
     elif re.match(r'^([+-])(([0-9]+)y)?[ ]?(([0-9]+)m)?[ ]?(([0-9]+)d)?$', date_arg):
         def get_offset(date_arg: str, signifier: str):
             if re.search(r'([0-9]+)' + signifier, date_arg):
-                return int(re.search(r'[+-]?([0-9]+)' + signifier, date_arg).group(0)[:-1])
+                return abs(int(re.search(r'[+-]?([0-9]+)' + signifier, date_arg).group(0)[:-1]))
             else:
                 return 0
 
@@ -124,7 +124,7 @@ def get_date(date_arg: str) -> date:
             return date.today() - relativedelta(days=days, months=months, years=years)
 
     else:
-        raise ValueError(_('The date {date} does not match the required YYYY-MM-DD format or the offset format.').format(date=date_arg))
+        raise ValueError(_('The date {date} does not match the YYYY-MM-DD format or the relativedate format.').format(date=date_arg))
 
 
 
diff --git a/manpage/kosmorro.1.md b/manpage/kosmorro.1.md
index 08f4170..08a23d2 100644
--- a/manpage/kosmorro.1.md
+++ b/manpage/kosmorro.1.md
@@ -23,7 +23,7 @@
     the observer's longitude on Earth
 
 `--date=`_DATE_, `-d` _DATE_  
-    The date for which the ephemerides must be computed (in the YYYY-MM-DD format); defaults to the current date
+    The date for which the ephemerides must be computed, either in in the YYYY-MM-DD format or as an interval formatted like [+-]YyMmDd; defaults to the current date
 
 `--timezone=`_TIMEZONE_, `-t` _TIMEZONE_  
     the timezone to display the hours in; e.g. 2 for UTC+2 or -3 for UTC-3