title: How can I retrieve the 'scheduled time' for catchup jobs in Airflow?
body: <p>When building an Airflow dag, I typically specify a simple schedule to run periodically - I expect this is the most common use.</p>
  
  <pre><code>dag = DAG('my_dag',
        description='this is what it does',
        schedule_interval='0 12 * * *',
        start_date=datetime(2017, 10, 1),
        catchup=False)
  </code></pre>
  
  <p>I then need to use the 'date' as a parameter in my actual process, so I just check the current date. </p>
  
  <pre><code>date = datetime.date.today()
  # do some date-sensitive stuff
  operator = MyOperator(..., params=[date, ...])
  </code></pre>
  
  <p>My understanding is that setting <code>catchup=True</code> will have Airflow schedule my dag for every schedule interval between <code>start_date</code> and now (or <code>end_date</code>); e.g. every day.</p>
  
  <p>How do I get the <code>scheduled_date</code> for use within my dag instance?</p>