Observer Support at the Telescope

A Support Astronomer (SA) will be present until approximately 23:00 local time on the first night of each WHT and INT run (apart from runs with established visiting instruments), to provide an introduction to the telescope, instrumentation and data-acquisition systems, and to safety issues. The SA will be on-call at the Residencia throughout the first night. Unless otherwise agreed, observers should meet their SA in the telescope control room at 15:00 on the first day of the run. Support Astronomers usually make contact with their observers several weeks before the start of the observing run. INT support is provided by student SAs.

The WHT 'observing support assistant' (OSA, an enhancement of the former 'telescope-operator' role) provides all-night, year-round operator and engineering support at the telescope. The OSA will be present at the telescope by half an hour before sunset (usually carrying out pre-observing checks) and will by default ensure, weather permitting, that by sunset the dome is open and the telescope is available for observing. If observers need the telescope on-sky earlier (e.g. for unusually-demanding sky flats) they should discuss this in advance with the OSA (or SA).

It's expected that on-sky observations will end during morning twilight. Occasionally, e.g. if the dome couldn't be opened in the evening, the observer may need to take sky flats in morning twilight. If so, the OSA should be warned about this during the night, and taking sky flats should not extend beyond 10 minutes after sunrise (NB flats taken in bright twilight can be done with the WHT pointing at the zenith, allowing the OSA to park the telescope). The OSA will only rarely be able to stay at the telescope longer than this, due to various constraints (including allowed shift length), and such observations may also conflict with daytime engineering access to the telescope.

The OSA's mobile-phone number is +34 616 97 45 13.

INT observers may call on the OSA for advice, but should be aware that the OSA usually has to stay at the WHT, and can't go to the INT to investigate problems. Critical technical problems which arise at the INT on weekends or public holidays, and which cannot be solved by the OSA, will not be addressed until the next working day.

There is no engineering support 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 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 +34 616 974513) or Residencia reception (phone +34 922 405500).

On normal working days, the operations-team staff will carry out only limited checks of the WHT and of the instrument scheduled for use that night. The telescope will usually be available to observers by 15:00. The operations team will not normally move any optical component in the instrument light-path (and if they do, the observers will be notified) but system restarts might change the detector readout settings. It's recommended that observers check during the afternoon that the instrument configuration has not been disturbed.

On a few working days (Christmas and New Year's eve, colour-coded light green on the schedules), there will be a reduced level of engineering support.

Only ING staff are allowed to move the WHT, or its dome or shutters.

Observers who have a long observing run at the INT, and who plan to change the observing team during the run, should let their SA know, well in advance of the run, the names of the observers and the date/s of the handover/s. Safety training will be provided for the new observers on the day of each handover.

Observers who wish to discuss any aspects of the run, after arrival on La Palma, but before the formal start-of-run introduction at the telescope, may want to arrange a preliminary meeting with their SA, perhaps in Santa Cruz, where the ING offices are located.

Manual changes of the configuration of an instrument during an observing run (e.g. changes of filter, dichroic or grating) will be accommodated if they were requested explicitly in the original observing proposal. Such changes will be made by ING staff, and must not be made by visiting observers at either the WHT or INT. At the WHT, manual changes to instrument configurations can also be made during the night by the OSA. At the INT, instrument configuration changes can only be made on normal working days, when appropriately-trained day-time staff are available to effect the changes.

Details of requested changes to the instrument configuration during a run should be confirmed with the SA well in advance of the run. Requests for configuration changes not specified in the telescope proposal will be handled on a best-efforts basis.

The INT/WFC is offered at a default rotator position angle of 180 degrees. When there is compelling scientific justification (which should appear in the original observing proposal), other rotator angles (0, 90 or 270 degrees) can be offered for the duration of the run. Changes of WFC rotator angle during a run are not permitted.

Inexperienced WHT and INT observers must be accompanied by an experienced observer. 'Inexperienced' here means unable, alone, to make efficient (and safe) use of the observing night, whether from general lack of observing experience, or from lack of experience with the specific techniques to be used. This lack of experience will not adequately be compensated by the start-of-run training provided by observatory support staff.

In addition, it is essential that INT observers have considerable end-to-end observing experience with medium-sized telescopes. INT observers are responsible for all aspects of operation, from opening the dome in the evening, and operating the telescope and instrumentation throughout the night, to parking the telescope and closing the dome at the end of the night or in the event of deteriorating weather conditions.

ING relies on student supervisors, and experienced members of proposing teams, to ensure that less-experienced observers prepare adequately for their observing runs, before travelling to La Palma.

If there is any doubt about whether intended observers have sufficient experience, the advice of the SA should be sought.

While observing alone at the INT, observers should always carry with them the lone-worker alarm, whose use will be demonstrated by the SA.

INT observers who need help should make contact with the WHT OSA at dinner time, or contact him/her in the WHT control room (telephone +34 922 405559 or 452 on Cisco phones). Since there is no OSA at the INT, observers are expected to move the telescope, dome and shutters themselves. If there is ice on the dome, or there are other doubts about how to proceed, the WHT OSA should be contacted.

ING has a well-equipped mechanical workshop, staffed during normal working hours by trained engineers. Observers requiring their services should contact the Head of Operations, opsheading.iac.es. With sufficient advance notice, assistance outside normal working hours may also be possible.