Fast Track Channel (FTC)

FTC 117A

The first call for proposals for the Fast Track Channel (FTC) is expected to be issued

late May-early June 2026

More information will be provided in a Town Hall meeting to be held on

May 20th, 2026, 16:00 CEST.

(Further details about the meeting will be provided in this page.)

Fast Track Channel (FTC)

 

Introduction

ESO has moved to a Yearly Cycle (YC) for its regular call for proposals since P117, as a result of recommendations spelled out in the Time Allocation Working Group (TAWG) report. These included the parallel introduction of a Fast Track Channel (FTC) to compensate for the increased length of the time between calls for proposals (see Patat et al. 2024).

The Fast Track Channel is intended to enable rapid access for new and timely scientific ideas, not to provide an alternative route for proposals that were unsuccessful in the previous regular cycle.

Proposals qualifying for the Fast Track Channel

The Call for Proposals contains information regarding the offered modes and instruments both for the main cycle (P117) and the FTC. It is the binding document for the science policies. The additional criteria specific for the FTC call are listed here:

  1. Only VLT or VLTI Normal programmes with a maximum time request of 30 hours can be submitted to the FTC (i.e. no time on La Silla telescopes, no Monitoring, Calibration or Large programmes). 
  2. Observations will be carried out in Service Mode only (with the possible conversion to designated Visitor Mode in case of need).
  3. GTO Programmes will generally not be offered in the FTC calls, unless a new instrument or mode covered by a GTO contract becomes available after the proposal submission deadline of the regular Yearly Cycle.
  4. Target of Opportunity modes (Rapid Responde Mode, ToO-Hard, ToO-Soft) will be offered.
  5. Reserved time: approximately 90 hours per UT (see Available time per telescope).
  6. There are no scientific constraints for proposal eligibility to the FTC.
  7. Resubmission of a proposal rejected in the previous regular Yearly Cycle is not allowed (see What constitutes a resubmission?).
  8. Further restrictions may be imposed (instruments, RA ranges, conditions, …) depending on the status of the execution queues (see Offered instruments and restrictions).
  9. The FTC calls will be publicly announced several weeks ahead of the deadline via a Science Newsletter and via direct emails to active PIs.
  10. FTC proposals will be evaluated using the same Distributed Peer Review (DPR) system used for some of the proposals submitted to the regular Yearly Cycle (see FTC proposal submission, review and scheduling).

Tentative timeline for the first FTC call 117A

  • Call release: end of May/early June, 2026. The call will remain open for 3 weeks.
  • Proposal submission deadline: mid-June.
  • Proposal review: mid-June until beginning of July (2-3 weeks).
  • Phase 2 submission: August (2-3 weeks).
  • Start of observations: September (or as soon as the phase 2 material is ready).
  • Observing period duration: four to six months. The exact time range will be announced in the formal Call for Proposals.

The exact dates will be announced in the final version of the Call.

What constitutes a resubmission?

As noted in the P117 Call for Proposals (p. 5): "a proposal submitted to the FTC will be systematically rejected if it is found to be a resubmission of a proposal previously rejected in the previous YC [Yearly Cycle] call." This means that proposals submitted to the FTC 117A call cannot be resubmissions of proposals rejected during the regular P117 call.

A proposal will be considered a resubmission if its primary science goals, hypotheses, or intended scientific outcomes are substantially the same as those of a proposal previously submitted by the same (or substantially overlapping) team, regardless of changes in targets, observing setup, or wording.

Clear resubmission cases

The following cases constitute plain resubmissions:

  • Reuse of the same or only lightly edited scientific justification text;
  • Same science case with:
    • different targets;
    • slightly modified observing strategy;
    • different instrument configuration.
  • Previously rejected proposal re-entered with cosmetic or incremental changes;
  • Splitting a previously rejected programme into smaller proposals without changing the science goal.

In general, a proposal will be considered as a resubmission if it could reasonably have been written by revising a previously rejected submission. While preparing a proposal for the FTC, the applicants should ask themselves the following questions:

  • Is the main scientific question different?
  • Are the expected results or impact meaningfully different?

If the answer is “no” or “not really,” it likely counts as a resubmission.

Likely Acceptable Cases

  • Proposals addressing clearly different scientific questions, even if in the same broader research area;
  • New ideas motivated by:
    • new theoretical developments;
    • new data;
    • recent discoveries.
  • Substantially revised concepts where:
    • the original hypothesis is replaced or fundamentally altered;
    • the expected scientific outcome is different.
  • Projects that build on earlier work but pursue a distinct objective, not just completion or repetition.

In ambiguous cases, the Observatory reserves the right to determine whether a proposal constitutes a resubmission based on its scientific content and intent.

Team overlap

The resubmission criteria apply to proposals from the same PI or substantially overlapping teams and are not limited to identical author lists.

FTC justification field

The Phase 1 proposal form includes a mandatory free-text field entitled FTC justification. In this field, applicants must explain why it was not possible to submit their proposal during the most recent regular call, and why the proposed observations cannot be deferred to the next regular call.

If a similar proposal was submitted by the same team in the previous regular call, applicants should also briefly describe how the present submission differs from that earlier proposal (see What constitutes a resubmission?).

This information will be used exclusively for internal purposes within ESO and will not be used in the evaluation of the proposals. It will not be made available to reviewers. As such, the text of this field does not need to be anonymised.

FTC proposal submission, review and scheduling

  • FTC proposals are submitted via the p1 proposal preparation tool by selecting the appropriate Cycle.
  • FTC proposals will be reviewed via a Distributed Peer Review (DPR). Each PI (or delegated reviewer) will have to review 10 FTC proposals per submitted proposal. Each FTC proposal will be reviewed by 10 peers who submitted proposals for the same FTC call.
  • The same rules and guidelines for the DPR as in the regular Yearly Cycle will apply.
  • The grade distribution of the FTC proposals will be normalised to the overall panels grade distribution of the associated regular Yearly Cycle.
  • The time reserved for the FTC will be filled using the proposal ranking provided by the FTC review.
  • The same cutoff grades attained for the regular cycle will be applied to the FTC on a telescope per telescope basis.
  • Proposals below the grade cutoff of the regular Yearly Cycle programmes at the given telescope will not be scheduled.
  • Poorly graded FTC proposals requiring poor observing conditions may be allocated as fillers in the C-rank queue to the discretion of the Observatory.
  • FTC runs inserted in the queues will have the priority which pertains to their rank. Once queued, there will be no difference with respect to runs from the regular Yearly Cycle.
  • If an FTC call goes undersubscribed, part of the time originally reserved for the FTC will be filled in with the highest-ranked, non-allocated runs of the associated regular Yearly Cycle.
  • The 10% fraction of Chilean time allocation will be computed on the full allocation per Period (i.e. yearly, not per single FTC call).

Available time per telescope

The schedule of the regular cycle P117 was built reserving approximately 15% of the science time between September 1st, 2026 and April 30th, 2027 for the Fast Track Channel. The expected approximate available time per telescope for the first FTC call (117A) is summarised in the following table.

Telescope

Time (hours)
UT1 80
UT2 95
UT3 90
UT4 85
VLTI-UT[*] 40
VLTI-AT 70

[*] For VLTI-UT there is no available time for turbulence category 30% or better (see Offered instruments and restrictions).

Offered instruments and restrictions

  • All instruments and instrument modes offered for the VLT/VLTI in the regular P117 cycle are available, except for visitor instruments (since Visitor Mode is not offered). See the Call for Proposals for P117.
  • For VLTI-UT there is no available time for turbulence category 30% or better. However, VLTI-UT proposals requiring more relaxed constraints are encouraged:
    • Turbulence category > 50% and Sky transparency = CLR
    • Turbulence category = 50% and Sky transparency = THN
  • The Observatory expects to keep the same distribution of VLTI baselines, i.e., no changes to the scheduled VLTI-UT nights, and only minor adjustments for VLTI-AT if needed by the top ranked FTC proposals. Applicants should check the distribution of the baseline configurations scheduled during P117 in the Observatory schedule, after selecting the desired range of dates on the top left menu of the interface.
  • No RA restrictions are envisaged at this stage.

Run validity and carry-over for FTC 117A

  • The time for FTC 117A is offered for observations to be carried out starting on September 1st, 2026 and extending for four to six months.
  • Approved, non-completed A-rank FTC runs will be carried over until the end of P117 (April 30th, 2027).
  • B-rank FTC runs will be terminated at the end of the FTC validity range.
  • FTC runs allocated in designated Visitor Mode (dVM) will not be compensated for possible weather losses.

Outlook

  • The future FTC time fraction and maximum time request per proposal will be tuned based on the outcome of the FTC 117A cycle, to keep the oversubscription similar to that of the regular Yearly Cycle.
  • A possible second FTC call (117B) will be considered based on the community response to FTC 117A.
  • The plan is to reduce the duty cycle[*] from 3 months to 2 months.

[*] This is defined as the time from the submission deadline to the start of first observations.

Frequently asked questions on the Fast Track Channel

Why has ESO introduced the Fast Track Channel?

ESO has introduced the FTC following the recommendations of the Time Allocation Working Group. The main scope of the FTC is to compensate for the increased length of the time between calls for proposals caused by the introduction of the Yearly Cycle.

Do I need to have a special science case for my proposal to qualify for the FTC?

No, any science case qualifies for the FTC. What is important is that it does not duplicate the science case of a rejected proposal submitted by you or by your team during the last regular Yearly Cycle (see What constitutes a resubmission?).

Why am I required to complete the FTC Justification field in the p1 proposal form? Will this information be considered during the scientific evaluation of my proposal?

The FTC Justification field is intended uniquely for internal use within ESO. It is primarily used by the Observing Programmes Office to collect statistical information on the use of this recently introduced proposal submission channel. In this section, you are expected to explain why it was not possible to submit your proposal during the last regular Yearly Cycle and why the proposed observations cannot be deferred to the next regular Yearly Cycle call. If your current proposal is similar to one that was rejected in the previous regular Yearly Cycle, you should also clearly describe how this submission differs from the earlier one. The content of the FTC Justification field is not considered in the scientific evaluation of your proposal, but it may be used to determine whether the submission constitutes a re-submission.

If I want a fast turnaround time, why not simply apply for Director's Discretionary Time (DDT)?

DDT proposals are for science observations that require a very fast turnaround timescales, which can range from a day to a few weeks, depending on the urgency of the science case. Also note that DDT proposals need to fulfill certain requirements, which are spelled out in this page. The Fast Track Channel, on the other hand, is appropriate for science targets that can be observed several months (>3 months for the FTC 117A call) after the proposal deadline.

Why is it not possible to ask for time on telescopes at the La Silla Observatory?

La Silla telescopes are fully allocated in Visitor Mode and hence it is not possible to add extra programmes once the yearly schedule has been released.

Why is the requested time for FTC proposals limited to 30 hours?

The 30 hours maximum request was set to align with the typical maximum request of regular cycle proposals reviewed via DPR. This limit may change in the future depending on the number of submitted proposals and their size distribution.

Will it be more difficult to obtain time via the FTC than via the regular Yearly Cycle?

This depends very much on the number of proposals submitted via the FTC. In general, the same cutoff thresholds used for scheduling the regular cycle proposals will be used when allocating the FTC proposals (per telescope). This will ensure that none of the two channels is favoured.

How was the time reserved in the schedules of the various telescopes?

The time was reserved by inserting free slots evenly distributed across the time range September 2026 to April 2027 (included). No time was reserved for FTC for the first four months of P117 (May to August 2026).

Will there be additional FTC calls during P117?

The plan is to have a second FTC call during P117, covering the remaining part of the period. A final decision about the release of a second FTC call will be taken after evaluating the results of the first FTC call.

I need additional information. Could you please help me?

You can submit your request via the ESO Operations Helpdesk. Otherwise you can access it from your User Portal account (under "Ask for Help/Contact us"). Please, include all the required details in your ticket, so that we can provide you with a prompt and comprehensive reply.

 

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Last update: Tue May  5 13:37:53 CEST 2026