ICE IAC
Rubin Observatory LSST DESC

LSST Internal GTC Call for Letters of Intent

Observing time at the Gran Telescopio Canarias available to the LSST community under the DESC in-kind programme

Through the Rubin Observatory International In-kind Program, the possibility to request observing time on the 10.4-meter Gran Telescopio Canarias (GTC) is being made available to the US and NOIRLab astronomical community. This time is contributed jointly via the Spanish in-kind initiatives ESP-BCM-S5 (Barcelona–Madrid) and ESP-IAC-S1A (Instituto de Astrofísica de Canarias). Approximately 2 nights will be available through this opportunity each semester.

This program offers a unique pathway for US- and Chile-based investigators to secure high-impact follow-up observations on a premier 10m-class facility. Any astronomer affiliated with a US institution or the Chilean astronomical community is eligible to apply.

Available Time

Approximately 2 nights per semester are available through this program under the in-kind contribution agreements ESP-BCM-S5 and ESP-IAC-S1A.

Semester A (Spring/Summer)

Period: March – August
Available time: ~2 nights

Semester B (Autumn/Winter)

Period: September – February
Available time: ~2 nights

Available Instruments

Time can be requested for any standard, currently operating GTC instrument, including OSIRIS+, EMIR, MEGARA, and HiPERCAM. The final availability of instruments for a given semester will be confirmed in the GTC Call for Proposals.

Capacity cap: The total time requested across all promoted LOIs will be capped at 3× the available allocation for the semester. Technical feasibility and scientific merit will guide the down-selection if this cap is exceeded (see Allocation Process).

Proposal Cycle & Key Dates

The proposal cycle runs backwards from the hard deadline of the Spanish TAC submission:

Jul 1

Announcement of Opportunity Released

The Announcement of Opportunity is published and this call opens. Eligible US and Chilean researchers may begin preparing their Letters of Intent.

Aug 7

Letters of Intent Due

Deadline for US/Chilean proposal teams to submit their Letters of Intent through this portal.

Sep 1

GTC Call for Proposals Released (exact date to be announced)

The official GTC Call for Proposals is released. Matched teams submit their full collaborative proposals through the standard TAC portal.

Oct 1

Full Proposals Deadline — Spanish TAC (exact date to be announced)

Submission deadline for full proposals to the Spanish Time Allocation Committee at proposals.iac.es. The exact date will be announced in the GTC Call for Proposals.

Allocation Process

1

Receipt and Assessment of Letters of Intent

Submitted LOIs are received and assessed by the in-kind program coordinators. Each LOI is evaluated for scientific scope, technical feasibility, and suitability for the collaborative framework before being assigned to a Spanish contact.

2

Technical Review & Matchmaking

The Spanish In-kind Coordination Team will evaluate LOIs for technical feasibility and capacity constraints. Successful LOIs will be paired with a Spanish host institution scientist who will serve as local co-PI and formal PI in the proposal submitted to the Spanish TAC.

3

Contacting PIs

Proposal PIs from the Barcelona–Madrid–IAC LSST groups will be contacted by the in-kind program coordinators. The PIs will then reach out to the US/Chile groups to convert the LOIs into full GTC proposals.

4

Selection if Capacity is Exceeded

If the cap on requested time is exceeded, the in-kind program coordinators together with the PIs of the Spanish LSST groups will select which LOIs are promoted to submitted proposals based on feasibility (observability, RA & Dec range, instrument choice, availability of instrumentation, and requested conditions). If feasibility cannot discriminate between LOIs, the selection will be based on scientific return as assessed by the Spanish in-kind program teams.

Letter of Intent (LOI)

All applicants must submit a Letter of Intent before preparing a full proposal. The LOI allows the committee to assess the scope of interest, assign Spanish contacts, and manage capacity. Submission of an LOI does not guarantee an allocation.

Requirements

Announcement of Opportunity: 1 July 2026
LOI Deadline: 7 August 2026

Submit Your Letter of Intent

Upload your LOI as a single PDF file using the form below. Make sure your document meets all requirements listed above before submitting. You will receive a confirmation on screen upon successful submission.

Click to browse or drag & drop your PDF here

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