• We recall that every proposal within the Spanish CAT scheme must be led by a principal  investigator (PI) affiliated to an Institution in Spanish soil.  GTC Spanish/UF proposals can have either a Spanish or Florida PI, and must include co-Investigators (co-Is) from both communities (see below).

• The start and end of the semester change with telescope as illustrated next:

  • INT, Stella, TCS: February – July.

  • NOT, TNG, Mercator: April – September.

  • GTC:   March – August.

  • WHT: May – October

  • Liverpool (LT):   January – August (a two-month overlap period is adopted at the start and end of each semester, when proposals from both semesters may be observed in order to reduce problems with under-filled observations queues).

• Large programs requesting observing time with any telescope (except for the TNG, WHT, and INT) are accepted. See below.

• Proposals requiring visitor mode (including GTC) should include a proper backup scientific program that does not demand good weather conditions. The backup program is also scientifically addressed by the CAT.

• All proposals must be submitted using the application http://cat.iac.es (more info at the end of this web page), with the only exception of WEAVE (WHT) proposals, which must be submitted using the specific ING platform created for the WEAVE instrument.

• Proposals are evaluated at the next meeting of the CAT (November 2023). Recommendations will be made to the Director of the various Observatories/Telescopes in December 2023.

Please, read carefully the following highlights and recommendations made for each telescope and for large programs. There are IMPORTANT changes (e.g., TCS, WHT, TNG, GTC, instruments unavailability) with respect to previous calls for proposals. Pay special attention to the new (latex, word, pages) form for the preparation of proposals (except for the WHT).

HIGHLIGHTS

What follows are the highlights of all seven telescopes managed by the CAT.

GTC

Detailed information about the feature of GTC for this semester is available here.

• OSIRIS, EMIR, HiPERCAM, and MEGARA are offered in this call.
• OSIRIS is offered at the Cassegrain focus station and with the new monolithic, blue-sensitive CCD.  
  • OSIRIS “imaging” (broad-band, SHARDS filters),  and “spectroscopy” (long-slit, MOS) modes are offered.
  • Tunable filters and “frame transfer and fast photometry” are not offered in 2024A.
  • Multi-Object Spectroscopy (MOS) observations will be part of the observing queue only if the proposals are ranked in bands A and B of the Spanish CAT final list. Because there is a new CCD, previous masks are no longer usable. All approved MOS proposals must build their new masks. 
  • OSIRIS new CCD is operating since January 2023.
• EMIR is offered with the new H2RG detector. 
  • EMIR broad- and narrow-band imaging, long-slit and MOS spectroscopy are the offered observing modes in 2024A. 
  • All applicants are recommended to read the instrument manual carefully.
  • The time needed to perform EMIR night-time calibrations (e.g., observations of telluric standard stars, wavelength calibration, etc.) will be charged to the observing programs. Therefore, applicants must include all the time needed to perform theses calibrations together with the time needed for the science observations in the total requested telescope time in their proposals.
  • EMIR new detector is operating since June 2023.
• MEGARA integral-field unit (IFU) is offered. The MOS mode will not be offered due to foreseen upgrades on the MOS positioners.
• For the calculation of overheads, the GTC Observatory strongly recommends the use of the following Phase 2 simulator. Further information on the calculation of overheads is provided in the GTC call for proposals.
• HiPERCAM is now permanently installed at the new Folded-CASS G focal station. It provides imaging capability in 5 channels (u’, g’, r’, i’, z’) simultaneously. Although offered to the GTC community, HiPERCAM is a visitor instrument (PI.Vik D hillon).
• Visitor programs are very welcome, but will only be admitted whenever they fall in bands A and B. In addition, a backup program (in visitor mode) has to be defined in the case the observing conditions for the main program are not met.  C-band proposals requesting visitor mode will be included in the observing queue, but are not admitted as “visitor”. The applicants must clearly indicate if they are applying for visitor mode or “remote visitor mode” (see below).
• Target-of-opportunity (ToO) proposals are accepted as regular programs (read carefully the ToO policy at GTC and as well as the GTC ToO page for further details). Large programs cannot contain ToO observations. ToO proposals will be recommended with their corresponding priority whenever they fall in bands A and B of the ranked proposal list. ToO proposals in band C will not be approved. ToO proposals do not have carry-over status.
• For all approved proposals (bands A, B, C, and filler), GTC Phase 2 information must be submitted to the GTC at the deadline corresponding to the semester in which the proposal is accepted.
• Large programs requesting OSIRIS (imaging and long-slit observing modes) and/or MEGARA IFU data are offered in 2024A. These programs must:
  • have the potential to lead to a major advance in a specific field of astrophysics,
  • require a minimum of 100 h of GTC CAT that can be distributed over 1 to a maximum of 4 semesters, with a limitation of a maximum of 100 h per semester,
  • must have a PI from any institute in Spanish soil (because the observing time is deduced from the CAT share), and 
  • must comply with the conditions, particularly those regarding dark, gray, and bright night time, described here.
• SPANISH/UF TIME: Up to 1.25% of the GTC observing time is reserved for collaborative proposals between Spanish and University of Florida astronomers. To send proposals under this agreement, select the Special Agreement“Spanish/UF Time” in the CAT application tool. 

• After publication of the GTC data, all PIs will be contacted by the CAB, CSIC-INTA, archive staff and invited to send their reduced data products for public release to the astronomical community through the GTC archive.

• The Observatory announces that the R. A. ranges 0 – 2 h and 12 – 14 h are highly over-subscribed, whereas the R. A. interval 20 – 23 h and bright moon time are generally less demanded. Programs that can use bright moon time and/or have targets with R. A. between 20 and 23 h  will have higher probability of being executed at the telescope.
• The Observatory encourages users to request Visitor Mode observations provided their programs benefit from this mode. The Observatory has successfully implemented a “flextime” mode intended to increase the efficiency of the visitor programs. Users interested in using this mode must declare it by ticking the “Visitor mode” button when filling in the electronic form of their proposal.
• Starting in semester 2020B, Remote Visitor Mode is also supported at GTC. Users interested in using this mode must declare it by ticking the “Remote visitor mode” button when filling in the electronic form of their proposal.
• Starting in semester 2019A, all proposals (including ToO) will be ranked in bands A, B, C, and filler. Principal Investigators of A-, B-, and C-ranked proposals and filler projects must complete GTC Phase 2 of ALL approved observations in due time. The bands assigned to each proposal are defined as follows:
  • A-band proposals have very high priority and all possible efforts will be made to execute all of the required/approved observations in the requested semester. If for any reason, A-band proposals remain unfinished by the end of the corresponding semester, the existing GTC Phase 2 will be granted an extended life-time of two additional semesters, or until its completion, whichever comes first. Unfinished A-band proposals do not have to be re-submitted in the following two semesters because of their carry-over status. Approximately one quarter (according to the CAT ranking) of the total amount of GTC available observing time falls in this band.
  • B-band proposals will be executed on a best-effort basis during the requested semester, and do not have a carry-over status. Approximately three quarters (according to the CAT ranking) of the total amount of GTC available observing time falls in this band. 
  • C-band proposals will be executed in extraordinary cases when no A- or B-band objects are available but the good weather conditions permit observations during the requested semester. C-band proposals do have very little opportunity of execution until completion of the project, yet they are included in the GTC observing queue. 
  • Filler proposals, see below.

PROTECTED OBJECTS. Due to the execution of Guaranteed Time Observations (GTO) of various instrumental teams, all applicants are kindly requested to check the list of protected objects here (follow the links to the corresponding instrument). Protected objects cannot be proposed for observation by other users, unless an instrumental setup different to that of the GTO is required.

FILLER PROPOSALS: In order to have an efficient queue-scheduled observations scheme for the GTC, it is useful to have a set of “filler” programs that can be executed under adverse observing conditions (bad seeing, poor sky transmission, etc.). Filler proposals can request common-user instruments (OSIRIS, EMIR, MEGARA) with simple instrumental configurations (filler proposals should not request complex observations that demand non-standard instrumental modes). These programs must contain targets spanning a wide range in right ascension (RA). Filler proposals will only be executed if the observing conditions do not permit observations of proposals in A-, B-, or C-bands. Proposers may request filler status for their program, and during the proposal selection process CAT will evaluate their suitability for this category. Such proposals can request a large number of observing hours. In order to be considered as filler proposals, they must fulfil the following requirements:

• Their observing requirements should be very relaxed, i.e. little or no restrictions on seeing or cloud coverage. 
• The chosen observing mode should be a frequently used mode .
• There is a scientific gain even if only a small fraction of the requested observations are executed.
• A list of targets with a broad R.A. coverage is provided or,  if only few targets are included, they must have good visibility during the semester.
• Filler proposals cannot contain Target of Opportunity (ToO) targets.

Note that filler proposals have generally been highly successful in the last semesters. 

Filler proposals must be identified by ticking the “filler” box in the proposal submission tool http://cat.iac.es.