Priorities for Visitor, Service, Technical, Reserved and Idle nights



Priorities for Visitor, Service, Technical, Reserved and Idle nights

Doc/issue LSO-PRO-ESO-90000-2
Date/issue/author/revision 2002-12-20, v1.0, ohainaut


  • SciOp: La Silla Science Operation Department
  • ToO: Target of Opportunity observations.
  • DDT: Director Discretionary Time
  • DDTC: Director Discretionary Time Committee
  • OPC: Observing Program Committee


  • Visitor time: a Visiting Astronomer is present at La Silla to perform his observing program. Overrides to this program are ruled by the Policy for ToOs.
  • Service Time: nights scheduled for Service Mode observations.
    • Delegated Service Mode: the night is allocated to one specific program, and the observations are performed by SciOp staff. The priorities for such night are as for Visitor Time, i.e. set by the Policy for ToOs.
    • Flexible Scheduling: SciOp staff will perform observations from a pre-defined pool (the "OB repository"). The priorities for these nights are as follow:
      • ToOs (both DDTC- and OPC-allocated).
      • Service Observations
      • DDT, ToO compensation, pre-imaging.
  • Technical Time: nights scheduled for maintenance and tests. Availability of the telescope or instrument is not guaranteed.
    Priorities for these nights are the following:
    • Urgent technical work,
    • ToO (both OPC and DDTC) - if technically feasible
    • Non-urgent technical work,
    • DDT (not time critical), ToO compensation, pre-imaging.
  • Reserved Time: nights scheduled for scientific observations, but reserved for DDT. Time must be requested following the DDT Policy, at least one month in advance for "non time-critical" observations.
    Once allocated, these nights become either "Visitor Time" or "Delegated Service Time".
    If the time is not assigned by the DDT Committee, these nights are automatically converted into Technical Time.
  • Idle time: the telescope is not operated. Urgent technical work can be scheduled during these nights, but no observations, as there is typically no staff to operate the telescope on these nights. Exceptions and override must be channeled to the Director General via La Silla.