Targets of opportunity

A Target-of-Opportunity (ToO) programme is one for which observations of a rare or transient event are required at short notice, and they can be justified by the unique scientific opportunity these observations represent.

Starting in semester 2026A, the ING offers Target of Opportunity (ToO) observations using the LIFU mode only. ToO proposals address unpredictable astronomical events that require immediate observation and whose timing does not align with the standard trimestral proposal preparation and OB submission cycle. Due to their disruptive nature, ToO observations will be capped at a maximum of 30% of the available Open Time for each national TAC every semester.

Applications for ToOs should be submitted to the TACs in the same way as regular proposals for scheduled time. ToO proposals will be evaluated in the same way as regular Open Time proposals but will only be scheduled if they are ranked in the highest category Band A.

Triggering teams of allocated programmes can submit their ToO requests using a phase-2 catalogue format, which ING will use to generate the observing blocks (OBs). The observing strategy at execution must match what was requested and approved in the proposal, and triggers must not exceed the allocated time.

At present, ING supports next day triggers: for an event scheduled to be observed on a given night, the trigger must be received by the Observatory no later than 12:00 noon on the preceding day. ING will strive to execute ToO programmes on a shorter timescale on a best-effort basis. ING anticipates executing at most one ToO trigger per night, on a first-come, first-served basis.

The reduced observations will be available on the WEAVE Operational Repository on a few days after observations.

Time-critical and monitoring observations

Time-critical observations (at a certain time) and monitoring programmes (repeated observations over a period of time executed at a given cadence) are possible. Please specify this scheduling mode at phase 1. For discussion on feasibility and instructions on how to proceed, please contact for details:

Proposals for poor conditions (filler mode)

ING encourages PIs to submit LIFU-mode proposals designed for poor observing conditions during bright time, when less proposals can be attempted, namely:

• Seeing ≤3.0"
  
• Transparency ≥0.4
  
• Elevation: ≥25.0° (X≤2.4)
  
• Moon distance: unconstrained
  
• Sky brightness: ≥17.7 V_mag/arcsec² (bright)

  Proposals submitted with OBSTEMP = XEFEG will be treated as queue fillers. If awarded time, these programmes will remain in the queue until completion or for up to 1.5 years, whichever comes first.

Long (or large) programmes

A long or large programme is one that it requests a large amount of observing time over several semesters to achieve the scientific goals of the proposal. This kind of programmes are not currently accepted.

MOS community fibres

Community fibres (access to fibres not used in another observer or survey configuration) are likely to be offered (at least some of these, depending on demand) once the WEAVE observations are running smoothly. Not currently offered.