title: GMT cron expression for a PST based schedule?
body: <p>I want to setup a cron schedule for running something every 30 minutes from 6:00am to 11:30pm daily, Pacific Standard Time. I'm setting this up on an AWS Lambda function, which works strictly with GMT.</p>
  
  <p>I first tried an approximation, ignoring DST:
  <code>0,30 0-7,14-23 * * *</code></p>
  
  <p>This gave a syntax error. What am I missing?</p>