No engineering support staff will be on-site during the following periods (local time):

Summer weekdays 16:00 - 19:30 (15:30 - 19:30 on Fridays)
Winter weekdays 16:00 - 18:30 (15:30 - 18:30 on Fridays)
Weekends, public holidays From dawn until 19:30 (18:30 in the winter)

During these periods, the telescope buildings will be locked (key available from the Residencia reception), and visitors working alone should carry the lone-worker alarm and the lone-worker mobile phone. In the event of an emergency, call the Observing Support Assistant (phone (0) 616 974513) or Residencia reception (phone (0) 922 405500).

A support astronomer is normally present until ~ 23:00 on the first night of each run, and remains on-call throughout that night.

At the WHT, the Observing Support Assistant (responsible for telescope operation, troubleshooting) will be present (or at least contactable, by mobile phone) from 19:30 (summer) or 18:30 (winter) every night.

INT observers should be aware that the Observing Support Assistant can be called on for advice, but usually has to stay at the WHT, and can't go over to the INT to investigate problems.