title: Cron expression for every hour and 30 minutes
body: <p>I have tried cron expression <code>30 * * * *</code>, but it runs starting of every hour.</p>
  
  <p>Source: <a href="https://crontab.guru/every-hour-at-30-minutes" rel="nofollow noreferrer">https://crontab.guru/every-hour-at-30-minutes</a></p>
  
  <p>Please guide for correct expression.</p>
  
  <p>Expected should be:</p>
  
  <p>If First run at 2019-09-10 18:30:00<br>
  then at 2019-09-10 19:30:00<br>
  then at 2019-09-10 20:30:00<br>
  then at 2019-09-10 21:30:00<br>
  then at 2019-09-10 22:30:00</p>