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Phase 2 Waiver Requests and Programme Change Requests

Phase 2 Waiver Requests

To ensure the observing efficiency and flexibility of Service Mode observing, ESO has implemented a number of rules, procedures and limitations on programmes scheduled for Service mode. Typically, these have to do with OB construction, observing strategy, or instrument modes available.

In some special cases it is possible to admit some justified exceptions to these rules with a reduced operational impact. However, it is necessary that the exceptions have been reviewed and authorized by ESO well in advance. The Phase 2 Waiver Request procedure is the channel to make this possible.

A waiver request, including a justification for the exception, is submitted by selecting the Waiver option in the Change Request tab in p2. Please note that justifications based on the reduction of execution overheads may not be accepted, as sequences of OBs or very long OBs decrease the flexibility of Service Mode observing and thus the operational efficiency. The request should be submitted at least 1 week before the Phase 2 deadline to allow for evaluation by the support astronomer including input from Paranal operations staff. In the following are listed general and instrument specific Phase 2 Waiver conditions.

Instrument independent conditions where a Phase 2 Waiver Request is needed

  • OBs that will take longer than one hour to execute.
  • Concatenated OBs that will take longer than one hour to execute.
  • Concatenated OBs that have large angular separations between the OB targets (>75 deg) which would result in a very difficult scheduling.
  • OBs that contain multiple instrument configurations. As an exception, multiple broad-band filters in a single OB can normally be allowed without a waiver, and for FORS2 up to two interference filters may be used in a single OB without a waiver.
  • Delayed submission of Phase 2 material needed. This is admissible only under exceptional circumstances justified by scientific reasons, such as the need to wait for the outcome of another observing run before preparing the OBs. Users whose schedule prevents them from submitting their Phase 2 package by the due date are strongly encouraged to find a collaborator who can do it, rather than submitting a waiver request, as ESO cannot guarantee the prompt review and validation of Phase 2 packages submitted after the Phase 2 deadline.
  • The time interval between succeeding time-linked OBs is < 1hr.

Additional conditions for Waiver Requests regarding FLAMES

In addition to the general Phase 2 Waiver Request policies, waiver requests have to be submitted for any of the following conditions:

  • if the submitted OB contains a Target Setup file, which is valid for less than +/-1 hours in hour angle;
  • the same fibre configuration must be observed always on the same plate of the positioner;
  • if you require any special calibrations, including attached flat-fields (with UVES and/or GIRAFFE mode) or any other daytime or nighttime calibrations.
  • if you use multiple setups within a single OB.
  • if you expect any saturation in any of the exposures of any of the OBs, either from the calibration fibres or science target(s) (e.g. bright emission lines).
  • use of any of the L385.7 / H379.0 / H395.8 / H412.4 settings with ARGUS.


Submission of Phase 2 Waiver Requests and Programme Change Requests

Waiver Requests are petitions to override one or more operational rules or technical limitations.  Programme Change Requests are petitions to deviate from observations as proposed at Phase 1 (e.g. new targets, new instrument, new/different observing modes, etc.).  Formulation and submission of both types of petition is now fully supported in the p2 (Paranal) and p2ls (La Silla) user interfaces. Once logged in, the user should select the Run for which they intend to submit the Waiver Request or Change Request. By clicking on the Run, the user will be able to access the Change Request menu on the top right.  Further information is provided here

Note that all Phase 2 Waiver Requests and Programme Change Requests must be approved by ESO before Phase 2 package submission. Users should understand that such requests can take a number of days to process, especially when consultation with the Chilean Science Operations team is needed.  Until they are processed no further progress can be made in processing of the run.  Hence users are strongly encouraged to plan ahead and submit such requests in a timely fashion.

All approved requests (either waivers or programme change) should be summarized in your README file.

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