WIXLIB

3 The p1 tool: The p1 tool for the preparation and submission of regular observing proposalswas deployed in Period 105. It represents the first part of a broader overhaul of the ESOPhase 1 system that also entails a significant modernisation of the Observing ProgrammesCommittee, refereeing process, and related tools. The p1 system is web-based, resembles thep2 tool, and includes many new features.There are some important practical implications: each of the CoIs will need to have anESO User Portal account with an updated affiliation and email address (the PI will addthe CoIs to the proposal using their corresponding email address). Please note that lastminute requests for the addition of institutes to the database cannot be accepted and must besubmitted at least one week before the proposal submission deadline. It will also no longer bepossible to directly resubmit existing LATEX proposals into the new system. Large Programmes (LP): Large Programme proposals are only accepted in even Periods,i.e., Periods with proposal submission deadline in March or April.Large Programmes can be requested to start either in the semester of the Call or in thesubsequent semester (the following odd Period), but the programme can extend at most overfour consecutive semesters from the semester of the Call (e.g., currently up to Period 111).Since Period 104, ESO strives to execute Large Programmes over shorter periods of time(aiming at two semesters by default), while maintaining the ceiling set by ESO Council of 30%of the observing time allocated to Large Programmes. Thus, from Period 104, the communityshould submit Large Programmes that do not extend over a number of Periods larger thanthat set by their scientific requirements.These measures follow the recommendations of ESO’s Time Allocation Working Group, reviewed by the Scientific Technical Committee and Users Committee, and aim at increasingthe scientific impact of ESO’s telescopes.See Sect. 4.4 for restrictions on instruments and modes for Large and Monitoring Programmes. Target of Opportunity (ToO) in Monitoring and Large Programmes: Starting inPeriod 106, Monitoring Programmes can include all types of ToO runs (ToO-Soft, ToO-Hardand ToO-RRM; see Sect. 4.8). Large Programmes can now also include Rapid Response Modeobservations (Sect. 4.8.2). Both Large and Monitoring Programmes can run up to four Periods,but Monitoring Programmes are restricted to less than 100 hours (see Sects. 4.2 and 4.3 fordetails on Monitoring and Large Programmes, respectively). Facility changes: Changes in any of the technical capabilities of the full ESO instrument suite in Period 108 can be found via the Recent Changes in Instrumentation webpage. Before writing a proposal for a given instrument, users are urged to check the instrument’s news webpage covering details not contained in this Call (e.g., for al/instruments/xshooter/news.html). Turbulence categories: Period 105 saw the introduction of turbulence categories as anobserving constraint for all instruments on La Silla and Paranal, whether they are seeinglimited or assisted by adaptive optics (AO) systems. With the advent of instruments usingdifferent AO modes, new atmospheric turbulence parameters need to be taken into accountin order to properly schedule observations and ensure that science goals are achieved. Theseparameters include the coherence time and the fraction of turbulence taking place in theatmospheric ground layer, in addition to the seeing.Users are encouraged to become informed on turbulence categories for Phase 1 and Phase 2on the observing conditions webpage, as well as instrument User Manuals for specifics perinstrument. The Exposure Time Calculators have been updated to reflect these changes. Invitation to submit proposals for larger Normal Programmes: ESO encourages thecommunity to submit proposals for Normal Programmes making use of the full allowed rangefor the total requested time, i.e., up to 99 hours (199 hours for nFLASH at APEX if requestingPWV 2 mm, see Sect. 1.1.4). ESO has been actively working to ensure that the distributionof requested time is matched, after the allocation and scheduling processes, by the distributionof allocated time, thus guaranteeing that proposals of all lengths have equal chances of success.

4 Proposal support: Since Period 105, and in order to improve the chances of proposal success, ESO encourages users to team up with, or seek advice from, members of the community who have submitted successful proposals in the past. As an additional option, usersmay also want to consider collaborating with ESO scientists with expertise on the scientific subject of their proposal. PIs interested in the latter option should send an email toscience p1support@eso.org with a title and abstract of their proposal, at least three weeksbefore the proposal submission deadline. This information will be seen by interested ESOscientists and treated as confidential. Guaranteed Time Observations (GTO): GTO will be carried out in Period 108 withGRAVITY and MATISSE (UTs and ATs), NAOMI (ATs) on any VLTI instrument, aswell as with ESPRESSO, SPHERE, MUSE, OMEGACAM, ULTRACAM, HARPSand ARTEMIS. Please see Sect. 4.5 for information on the number of nights allocated toGTO programmes in Period 108. For details about the protected targets, please gto/108.html.1.1.2Paranal Rapid Response Mode (RRM) activation policy: The RRM policy changed startingin Period 105: on-going observations on any VLT instrument can be interrupted by an RRMtriggered on that specific UT, even if the trigger requires a change of focus, unless the relevantprogramme is specifically protected against an RRM trigger (in case of strictly time-criticalprogrammes). The change will be operational by the start of Period 108 at UT1 and UT2, andmay be ready at UT3 for the start of the Period. It is expected to be operational at UT4 laterduring Period 108. Users are urged to read Sect. 4.8.2 describing details of the new aspect ofthe RRM policy. VLT-XMM proposals: It will not be possible to apply for VLT-XMM time in Period 108;proposals under this scheme will be invited again in Period 109. Distribution of UT instruments: For Period 108 the distribution of offered instrumentson the UT foci is shown in Table 1. ESPRESSO can be operated from any of the four UTs in1-UT mode and employs the four UTs simultaneously in 4-UT mode.Nasmyth ACassegrainNasmyth BUT1Visitor Instrument (Sect. 3)FORS2KMOSUT2FLAMESVISIRUVESUT3SPHEREX-SHOOTERUT4 - AOFHAWK-IICCFCRIRESMUSEESPRESSOTable 1: Distribution of offered UT instruments in Period 106. Remarks on UT instruments:– CRIRES: The upgraded instrument is offered to the community with the spectroscopymode covering the wavelength range 0.95 – 5.3 µm, with spectral resolving powers of50,000 and 100,000, and in noAO and NGS modes. A set of two gas cells allows highprecision radial velocity measurements. In Period 108, only targets that serve as guidestars can be observed (i.e., no off-slit guiding is offered). For NGS mode observations, thetarget must also be used as NGS (i.e., no off-axis AO correction is offered). Additionalobserving modes continue to be commissioned.

5– The extension of the GALACSI NFM tip-tilt limiting J-band magnitude to 17 mag isexpected to be commissioned in April 2021, and to be available from then on. Detailswill be available on the news page of MUSE.– ESPRESSO: Since Period 107, ESPRESSO is offered with the 4x2SLOW binning andreadout scheme in high resolution mode. This configuration is suited to science casesthat involve very low S/N while using only one UT.– VISIR is expected to be mounted by the end of August 2021 at the UT2 Cassegrainfocus, and to be available during Period 108.– The UT1 Nasmyth A focus is available for a Visitor Instrument during Period 108. Remarks on Survey Telescopes:– Period 108 is the last Period for which the operation of VST is guaranteed under thecurrent agreement between ESO and INAF.– Period 108 is expected to be the last Period of VIRCAM operations before the start ofthe modifications required at VISTA for the installation of 4MOST.– Normal and Large Programme proposals are accepted for OMEGACAM in Period 108without restrictions on atmospheric conditions, lunar phase or RA range, with the understanding that Large Programmes can only run for a maximum of one Period. Inaddition, the carry-over of incomplete observations to future Periods is not expected tobe possible. Proposals that waive proprietary rights are encouraged.– Large Programme proposals are not accepted for VIRCAM in Period 108 to allow thesuccessful completion of the ongoing Public Surveys.– Target of Opportunity (ToO) proposals are accepted for both VST and VISTA. Remarks on VLTI Operations:– Support for VLTI proposals: For VLTI users needing assistance to prepare their VLTIproposals, the community-supported VLTI Expertise Centres – distributed throughout Europe – can offer in-depth support. They also offer support for observation preparation, advanced data reduction and analysis.– VLTI Imaging: In Period 108, ESO will continue a scheme to optimize operations foraperture synthesis (imaging) with the VLTI. This scheme only applies to Service Modeobservations with the ATs. The reader is referred to the Period 108 VLTI manual forimaging requirements: observing mode, minimum requested time and minimum timerange. It is highly recommended to request imaging in SM. Imaging proposals requestingVM are expected to present a strong justification.As of Period 108, ESO introduces imaging slots (ISLs) in the VLTI-AT telescope schedule, in order to further improve the efficiency of VLTI imaging observations. ISLs areperiods of about two weeks of uninterrupted service mode, with flexibility on the exactdates to change the AT configurations. The ISLs are specifically set aside and centredaround new moon in November, February, May, and August of every year. PIs of GTOprogrammes, Large Programmes and programmes requiring Visitor Mode are requestedto adhere to this restriction for their planning. ISLs are primarily intended to supportimaging observations, but they are not restricted to this type of VLTI observations. ISLsare regular SM time, and OBs are executed according to their priority. Likewise, imagingobservations are not restricted to ISLs, but can be completed in SM time outside of theISLs.– Relocation configurations: For operational reasons, observations may occasionallytake place on relocation configurations during a transition between two standard configurations. A criterion of at least 50% baseline length overlap will be used. This scheme willbe primarily used for imaging runs. The overlap in baseline length between standard andrelocation configurations is detailed in the VLTI Configurations Overview webpage.– VLTI-UT operations: Due to the first phase of the recoating of the four UT Coudétrains, the UTs will not be available for VLTI for six weeks at the beginning of Period 108.

6 Remarks on VLTI Instruments:– GRAVITY (astrometric measurements): ESO invites proposals with the goal ofperforming astrometric measurements, a capability which is still under development(see, e.g., the following articles: Gravity collaboration, 2017, A&A 602, A94 andThe Messenger 170, 10). Proposers who wish to use the astrometric capability andcontribute to its development are invited to consult the GRAVITY webpage and contactthe astrometric team at least two weeks before the proposal submission deadline.– MATISSE is offered in Period 108 on the UTs (supported by the visible MACAO AOsystem), and on the short, medium and large AT configurations in Service and Visitormodes. MATISSE is offered with restricted use of GRAVITY as an external FringeTracker in the so-called GRA4MAT mode on the ATs only.1.1.3La Silla Distribution of La Silla Instruments:In Period 108 the distribution of offered instruments on the La Silla foci will be:– 3.6-m: Cassegrain (fibre-fed): HARPS– NTT: Nasmyth A: SOFI Cassegrain: ULTRACAM Nasmyth B: EFOSC2 NIRPS: the Front End Adaptive Optics and the Back End of the Near Infra-Red PlanetSearcher continues to be commissioned at the 3.6-m telescope in Period 108. The installationof NIRPS is not expected to affect the operation of HARPS in Period 108. The Visitor (Cassegrain) focus of the 3.6-m telescope is not offered during Period 108 due tothe installation and commissioning of NIRPS. The possibility of offering this visitor focuswill be re-evaluated in the future. The installation and commissioning of SoXS are expected to start during Period 109. Asa consequence, SOFI is expected to be decommissioned shortly before, either at the end ofPeriod 108 or during Period 109, and EFOSC2 is expected to be decommissioned at the endof Period 110. Large Programme proposals will be accepted for SOFI during Period 108 only and forEFOSC2 during Periods 108 through 110 only. Users should be aware, however, that theseprogrammes may be terminated ahead of the expected time, depending on progress in theactivities with SoXS. This will be reviewed again for Period 110. ULTRACAM: This PI instrument is offered to the ESO community for up to 5% of the observing time at the NTT in Period 108. Large Programmes will not be accepted. Operation ofthis PI instrument requires the presence of the instrument team, so ULTRACAM programmeswill preferentially be scheduled contiguously on periods of several nights. For questions onthe instrument and observation strategies, users shall contact the instrument PI, Prof. VikDhillon (vik.dhillon[AT]sheffield.ac.uk), at least two weeks prior to submitting their proposal.The ULTRACAM consortium is committed to support the PIs and observers from the ESOcommunity that have been awarded telescope time with ULTRACAM. The ULTRACAM teamwill support the execution of the observations and the subsequent data reduction to allow thescientific exploitation of the data obtained with ULTRACAM. Proposers must check that theirplanned observations do not duplicate any protected targets specified for ULTRACAM in thePeriod 108 GTO target protection webpages.

71.1.4Chajnantor ESO time: In Period 108, ESO’s observing time slots are foreseen to be August 15 – September6, October 21 – November 2, and December 8 – 20. Time critical observations should only berequested within these time slots. For a detailed description of the APEX instrument capabilities and links to observing time calculators, see the APEX instrumentation webpage.Users are encouraged to check the latest version of the schedule e-2021/. Large Programmes: APEX programmes requesting more than 99 hours should be requestedas a Large Programme (Sect. 4.3), except for the specific case of nFLASH-230 proposals thatrequire PWV 2 mm, for which the length limit for Normal Programmes is 199 hours. SeeSect. 4.4 for restrictions on instruments and modes for Large and Monitoring Programmes. ARTEMIS: In Period 108, both the 350 µm and 450 µm channels are offered for simultaneousobservations. This instrument is optimised for wide-field mapping of areas of at least 40 20 ,and achieves similar mapping speeds at both wavelengths. An observing time calculator isavailable at bscalc/. nFLASH: This facility instrument contains two receivers: nFLASH-230, covering from 200to 270 GHz, and nFLASH-460, covering from 385 to 500 GHz. Both are dual polarisation2SB receivers, and can be used simultaneously or independently in Period 108. The nFLASH230 receiver has an IF bandwidth coverage of 8 GHz with a gap of 8 GHz between the twosidebands; the nFLASH-460 receiver has a IF bandwidth coverage of 4 GHz per sideband.The backends are digital 4th generation Fourier Transform Spectrometers (dFFTS4G) with24 GHz bandwidth. An observing time calculator is available tor/ns/index.php. SEPIA: This instrument houses three ALMA-type 2SB dual polarization receiver cartridges:SEPIA-180 (ALMA Band 5) covering from 159 to 211 GHz; a new SEPIA-345 (ALMA band7) receiver covering from 272 to 376 GHz; and SEPIA-660 (ALMA band 9) covering from578 to 738 GHz (note the extended frequency coverage with respect to the ALMA band 9receivers). All receivers are available for Monitoring and Large programmes. All receivers usethe dFFTS4G backends, covering the 4 GHz (for SEPIA-180) or 8 GHz IF bandwidth with agap of 8 GHz between the image and signal bands. An observing time calculator is availableat lculators/.1.21.2.1Important remindersGeneral ESO User Portal: Proposals are submitted via the p1 proposal preparation tool. It requiresusers to log in with their ESO User Portal credentials. Further, all CoIs are required to havean updated ESO User Portal account. PIs will add CoIs to their proposals by submitting theCoI’s email address. Therefore, both PIs and CoIs are required to keep their affiliations ande-mail addresses up-to-date in the ESO User Portal. OPC evaluation of proposals: Proposers should keep in mind the need for each OPC panelto cover a broad range of scientific areas. As a result, a particular proposal may not fall withinthe main area of specialisation of any of the panel members. Proposers should make sure thatthe context of their project and its relevance for general astrophysics, as well as any recentrelated results, are emphasised in a way that can be understood by their peers regardless oftheir expertise. Observing conditions: The definitions of the observing conditions for Phase 1 and Phase 2can be found on the Observing Conditions webpage. Mistakes in, e.g., the lunar illumination requirement cannot be corrected after the deadline. Any-weather proposals: ESO strongly encourages programmes that can effectively exploitthe worst observing conditions on the VLT. More specifically, ESO invites proposals thatrequest turbulence category 85% or 100%, thin/thick clouds and have no moon constraints.

8 Justification of requested time and observing constraints: Users must provide inthe Time Justification field of the proposal all details necessary to reproduce their ETCcalculations to justify the time and observing constraints requested. Failing to do so may resultin the Observatory concluding that the programme is not feasible. Further justification of theobserving constraints can be provided in the Lunar Phase and Constraints Justificationfield. Policy on requests for changing or adding targets: Teams asking for observationsthat envision the need for additional or a change of targets, or for adapting their observingstrategy after the start of the Period (following, e.g., Gaia data releases), must declare itwith a note in the Special Remarks field of the proposal. The note must include the timescale and the expected cadence of the target change requests. In addition, the proposalsmust provide scientific and technical justifications for such approach in their rationale andTime Justification field. The request will undergo a scientific review by the OPC and atechnical feasibility assessment by the Observatory. Proposals that are scientifically highlyranked and can be supported in terms of target list changes and strategy requirements will beconsidered f

Proposal anonymisation: Period108 marks the full deployment of the Dual-Anonymous Peer Review (DAPR) in the evaluation of proposals for observations at ESO telescopes. Applicants must formulate the scienti c rationales of their proposals following the anonymi-sation rules and examples described in this link, which also gives a detailed .