Up to 5% of the available general observing time may be used for Director's Discretionary Time Proposals (DDTs). These programmes are generally of short duration (< 5 hours), though a longer time request may be granted if justified by a strong science case.

Only DDT proposals belonging to one of the following categories will be considered: 

• proposals of ToO nature requiring the immediate observation of a sudden and unexpected
  astronomical event;

• proposals requesting observations on a highly competitive scientific topic;

• proposals asking for follow-up observations of a programme recently conducted from ground-based and/or space facilities, where a quick implementation should provide break-through results;

• proposals of a somewhat risky nature requesting a small amount of observing time to test the feasibility of a programme.

The availability of the Fast Track Channel (FTC) at the VLT implies that only DDT proposals whose execution cannot wait until the next FTC can be considered.

DDT proposals may be submitted at any time. They must be prepared using the p1 proposal submission tool (see the p1 help webpage for further assistance). All co-Is must have an updated account in the ESO User Portal. DDT proposals must follow the anonymisation rules and guidelines.

Urgent observations: please use the Time Contraints and clearly indicate the urgency of a DDT proposal in the 'Special Remarks' field. The presence of Time Constraints is automatically detected and can ensure a fast processing of urgent requests.

DDT proposals are reviewed by a DDT committee, which issues recommendations to the Director General, or their delegate. Very few non-time-critical DDT proposals are foreseen to be approved. Proposing teams should provide a clear justification, in the 'DDT Justification' field, on a) why the programme should be considered for DDT allocation and was not submitted through the latest regular Call for Proposals or FTC call, and b) why the proposal cannot wait until the next FTC call. In the absence of such a justification, the proposal will not be considered for DDT allocation, and the proposers will be encouraged to resubmit their proposals in the next  Call for Proposals (either for the regular Period or the FTC). As a general rule, proposals originally submitted in the regular cycle and that were not allocated time should not be submitted as DDT proposals. If the proposed DDT observations were already submitted as part of (or complementing) a proposal of a regular Period or FTC, the Programme ID of the previously submitted proposal should be indicated in the 'Special Remarks' field. Approved DDT proposals are carried out in Service Mode on Paranal or in Visitor Mode override on La Silla.