Backup Targets

Introduction and Policy

During run in Visitor Mode, you are expected to perform the observations described in the approved proposal. This includes the specified targets and instrumental set-up(s).

  • Additional Targets: Make sure you have enough targets for the whole night. In case you need more to fill the night, additional targets must be requested and approved in advance.
  • Backup targets: Similarly, you should have a backup programme in case conditions do not permit your main programme to be executed. In particular, keep in mind that strong wind often comes from the North, so backup targets to the South should be prepared. Backup targets must be requested and approved in advance.
  • Change of set-up: in case you want to use an instrumental set-up not considered in the approved proposal, this must be requested and approved in advance.

In case the changes are not approved (or not requested), you will have to stick to the original targets and set-up. If these observations cannot be performed (e.g. because of high wind) or are useless (e.g. seeing significantly larger than the seeing constraint in the approved proposal), the telescope will be used by the observatory staff to perform Service Mode observations or Test/Technical operations.

Approval of additional targets, backup targets, or setup changes for Visitor Mode runs must be sought at least two weeks in advance of the observing run through the form below. Requests sent on shorter notice, in particular, less than 48 hours from the start of the run, may not be processed in time. In those cases, the corresponding data will not be accessible from the ESO Science Archive Facility until the request is approved.


Change requests need to be submitted using the following webform:

USDTarget/Set-up change request form.

Have your User Portal ID and password ready, as well as your run-ID.

You will receive immediately an acknowledgement, and later a reply indicating whether the change is approved or not, and the telescope will be notified.