1. Go to calendar.google.com. Log in if prompted.
2. On the left side, find "Other calendars" and click the down arrow .
3. Select Add by URL.
4. Copy the iCal link below and paste the URL of the calendar into the Google field.
5. Click Add calendar. The calendar will appear on the left side under "Other calendars."
6. It may take up to 12 hours for changes to show in your Google Calendar.

The Optical Society (OSA) Calendar: