New and Notable Changes in 2026B

The following capabilities and announcements are notable for the 2026B semester. Please see the relevant instrument pages and subsections of the call for proposals for details.

About DARP:
  • Korea has installed the DARP (Dual Anonymous Review Process) system from 25B semester. All Gemini proposals requesting time from the US, CA, BR, or AR have been following the DARP policy since 2021. For Korean Gemini Users, 1yr (or plus) of a grace period (i.e., no penalty to proposals that do not meet the DARP policy) will be given so that they can be well-trained/prepared for the DARP system. Korea will fully adopt the DARP policy in the proposal review process from 27A .

    Here is a brief summary for the DARP policy:

    Guideline for PIs

    • Enter information of the proposing team with the Phase I Tool (PIT) as usual.
    • Use the FT specific template.
    • The proposal template has been updated to be compliant with DARP starting on Feb 1, 2021
    • Avoid mentioning names and affiliations of the team in the PDF attachment that could be used to identify the proposing team.
    • Avoid claiming ownership of past work. (E.g., “my successful Gemini program in the previous semester (GS-18A-xxx)”, or “our analysis shown in Doe et al. 2020…”)
    • Including text in proposals discussing previous use of Gemini is ok, as long as that work is not referenced and program IDs are not listed.
    • Cite references in passive third person, e.g., “Analysis shown in Doe et al. 2020”, including references to data and software.
    • Do describe the proposed work, e.g., “We propose to do the following…”, or “We will measure the effects of …”
    • Unpublished work can be referred to as “obtained in private communication” or “from private consultation”.

    Guideline for Reviewers

    • Accept the assigned proposals based on abstracts, whether you can provide an unbiased review or not.
    • Review proposals solely based on the scientific merit of what is proposed.
    • Do not spend any time attempting to identify the PI or the team. Even if you think you know, you can be wrong.
    • Utilize neutral pronouns (they/the PI/the team) when you write comments.
    • Flag the proposals that have not been sufficiently anonymized, but DO NOT penalize them by lowering grades. (The FT support team will check the flagged proposals and send any violations to the Gemini Directorate for review.)
General:

The following capabilities and announcements are notable for the 2026B semester. Please see the relevant instrument pages and subsections of this Call for Proposals for details.

  • All proposals to use Gemini in 2026B must use the 2026B Phase I template. When preparing PDF attachments, please follow the proposal template font-size requirements in all cases and avoid using smaller fonts in any sections of Gemini proposals (including figures and tables).

  • Classical mode observing is offered in semester 2026B for facility instruments only.

  • Priority Visitor (PV) mode is offered at both Gemini North and Gemini South. If circumstances preclude having people on-site, programs awarded PV time will revert to queue mode. PIs requesting PV observing mode must state in their technical justification how the observations could be done in queue mode (with remote eavesdropping for data quality assessment and decision making). The "Bring One, Get One" Student Observer Support Program remains unavailable for semester 26B.

  • Rapid Target of Opportunity (rToO) Proposals: These can be accommodated for most instruments and their modes (and this includes non-LGS modes), subject to instrument availability on the dates upon which observations are triggered.

  • The Once in a Rubin Gem Director’s Discretionary Program will use Gemini South and North Rapid Target of Opportunity observations to characterize the early evolution of the most exciting and unexpected discoveries from the Rubin Legacy Survey of Space and Time. The observations will have no proprietary time and will adhere to the same Competitive Target of Opportunity policies as other Director’s Discretionary Time programs. As a rule, they will receive lower priority than QUEUE ToO programs. Specifically, a Rubin Gem that duplicates the observational setup of an existing Queue ToO program already activated for the same target will not be executed. However, if both the Gem and the QUEUE program trigger during the same night, priority will be determined by the temporal order in which the triggers are activated. More information about observing criteria and strategy can be found on the Program’s Website.

  • Timing Windows. Please provide all timing windows throughout the semester that are associated with your targets (timing windows added after the proposal submission deadline will normally be rejected). Timing windows must be specified by indicating the start time in UT, followed by the duration (in hours and minutes); for example: 2025-11-08 05:38:00 04:25. Ensure the format follows: yyyy-mm-dd hh:mm:ss hh:mm. We strongly recommend organizing the TW in a table format.

  • GMOS On-Sky Arcs: GMOS baseline arcs are now taken on sky, mixed with the science observations. For details on the updated GMOS arc baseline policy, please see this page.

  • Gemini North Engineering Time: Shutdown time for GNAO-LGSF tasks will require three weeks. The anticipated dates are between Oct 19, Monday, and Nov 06, Friday. These dates are provisional and may be subject to change. Unlike a standard A&G shutdown, all instruments are expected to be ready for observation on the night immediately following the shutdown's conclusion. The 26B shutdown will limit the availability of targets that are observable at RA 20 - 23 hours, and alternative targets should be prepared.

  • Gemini North - This Semester, Gemini North is pre-scheduling instruments on the bottom (up-looking) port (link). These are IGRINS-2 and MAROON-X. PIs with particular timing requirements (e.g. for transit observations) must note the dates of availability, and request observations for when the required instrument is on the telescope. There will be no, or minimal, adjustment of these blocks. You may note windows outside of these dates as backup in case the schedule changes for some reason.
    When installed, IGRINS-2 will operate as a regular facility instrument in the multi-instrument queue with GMOS and GNIRS.
    When MAROON-X is installed, it will be operated either by staff at the University of Chicago as single instrument (one-week blocks, shown in darker orange on the instrument schedule) or by Gemini staff in Hawaii in multi-instrument queue (lighter orange).
    Rapid ToOs will be accepted at all times, using any instrument mounted on the telescope.

  • Gemini South is expected to be closed for the first 7 nights of semester 26B (August 01 - 07).

  • Gemini South - GHOST PIs to receive reduced data products: The US NGO, in collaboration with Gemini, will offer reduced spectra for GHOST programs from all partner countries. The reduced files will be available through the Gemini Observatory Archive, together with the raw data. More information can be found here.

  • Gemini South - GSAOI and GeMS are decommissioned and will no longer be offered in this and future semesters.

  • The Gemini Observatory Graduate Student Visitor Program is temporarily suspended for semester 26B. Details of the Graduate Student Visitor program are available here.

  • Preparing for the Gemini Program Platform (GPP). We are expecting to use the new Gemini Program Platform (GPP) for the 2027A call for proposals. Depending on project progress GNIRS IFU/imaging, GMOS IFU, GMOS/F2 MOS, and `Alopeke/Zorro may not be available for the entirety of 2027A.

Phase I Submission Guidelines:

Proposals for time on Gemini, and for time on Subaru via the Gemini-Subaru time exchange program, must use the Gemini Phase I Tool (PIT). Latex and Word templates are available to create PDF attachments that include the science and technical cases, and investigator information. The template has been revised to enable the anonymous review process, and to make proposal requirements uniform across the partners. Two attachments are required for the proposal so that team information can be separated from the science case. PIs with targets that can be observed from either Gemini North or South (e.g., equatorial targets to be observed with one of the GMOS instruments) can request time with both instruments; in that case, the time with each instrument should be halved, and the Observatory will update the observation times when targets are scheduled.

All Gemini proposals requesting time from the US, CA, BR, KR,  or AR must be anonymized. Proposals which do not meet the guidelines will be penalised. This applies to proposals requesting time only from these partners, as well as joint proposals requesting time from multiple participants that include any of these partners. This requirement applies whether the PI or a co-I has the relevant partner affiliation.

Specific Timing Windows: In order to maximize the chances of completing observations with timing windows, 26B proposals should:

  • Provide a clear indication of the need for timing windows at Phase 1. Please provide all timing windows throughout the semester that are associated with your targets. Any additional timing windows requested by PIs after the proposal submission deadline has passed will not normally be approved. Timing windows should be entered in the "Scheduling" section of the PIT. Timing windows must be specified by indicating the start time in UT, followed by the duration (in hours); for example: 2025-11-08 05:38 04.25. Ensure the format follows: yyyy-mm-dd hh:mm hh.hh..

  • Use observing constraints appropriate to the expected lunar conditions. For example, if the only timing window for your proposal occurs during dark time, you should make sure to choose SB20 or SB50 as appropriate. Similarly, if you have a monitoring program with a cadence of a few days, you should define two sets of observations in the PIT, one with SBAny for bright time and another alternative option with SB50 for dark time (to allow for possible changes in sky brightness within the usable period).

Additional options in the Time Requests module in the PIT are available for semester 2026B:

  • The Gemini 2026B Phase 1 Tool includes options to specify that the proposal is for the AEON multi-telescope-facility system.

  • Also in the 2026B Time Requests module, there is an option to identify proposals which have synergies with James Webb Space Telescope science. The goal for providing this proposal category is to encourage development of science programs that benefit from a combination of Gemini and JWST observations.

Time for baseline partner calibrations is automatically added to the total time requested for each target in the PIT. You should continue to include the time associated with overheads (acquisition time, readout time, etc.). The ITC output gives overhead estimates. 'Alopeke and Zorro PIs should include program time for PSF standards if they need them. IGRINS-2 users will have several options in the “Night Basecal Time” in PIT; it will be possible to choose between default standards (1 standard every 1.5h), one telluric, two tellurics, or no standard.

Target of opportunity proposals must include all instrument configurations needed for the proposed science case, at Phase 1. This enables automatic creation of templates, and avoids errors at Phase 2.

Observable Targets in 2026B

Gemini North:

  Accessible Restricted** Inaccessible
Declination (non-LGS) -30° to +73° -37° to -30°, +73° to +90° < -37°
Declination, LGS -22° to +65° -27° to -22°, +65° to +68° < -27° and > +68°
Right Ascension (non-LGS) 19h to 11h 17h to 19h, 11h to 13.5h 13.5h to 17h
Right Ascension, LGS 20h to 10h 18h to 20h, 10h to 12.5h 12.5h to 18h

** Due to limited sky availability during the semester, GMOS MOS programs requiring pre-imaging should not have targets in this region, and other programs with targets in this region should not require a large amount of time, or have strict timing or observing constraints.

Gemini South:

  Accessible Restricted** Inaccessible
Declination (non-LGS) -87° to +22° -90° to -87°, +22° to +28° > +28°
Right Ascension (non-LGS) 19h to 9h 16h to 19h, 9h to 12h 1h to 5h

** Due to limited sky availability during the semester, GMOS and FLAMINGOS-2 MOS programs requiring pre-imaging should not have targets in this region, and other programs with targets in this region should not require a large amount of time, or have strict timing or observing constraints.

Instruments offered in 2026B

Gemini North:


Targets are generally limited to 17 < RA hours < 13.5 and -37 < DEC degrees < +90. Additional constraints are described in the target accessibility and instrument restrictions page of this Call for Proposals. Note that the RA ranges with limited accessibility near the start and end of the semester are typically in very high demand, and so prospective PIs may wish to consider avoiding targets with these RAs, where possible.

Facility instruments offered in 2026B are:

  • Altair AO system : The NGS mode (for GNIRS observations) will be offered in 26B. The availability of Altair LGS+P1 (super-seeing) mode will be confirmed once the current issue is resolved. Following the investigation, an update regarding Altair's availability and any potential impact on the telescope will be provided on the Altair Announcements page.

  • GMOS North (0.36-1.03 micron imager and spectrometer): Available throughout the semester. The GMOS-N B600 grating will not be offered because of its degraded sensitivity . The R600 grating will only be available for classical observing.

  • IGRINS-2: New high-resolution (R~45,000) near-infrared spectrograph covering the wavelength range of 1.49-1.80μm (H-band) and 1.96-2.46μm (K-band) in a single exposure. Offered during specific blocks, subject to RA demand.

  • GNIRS (1-5 micron spectrometer): Currently anticipated to be available in all operational modes for 26B: imaging, longslit, XD, LR-/HR-IFU, all with the possibility of being AO fed (subject to the availability of Altair). Additionally, ShortRed camera, which provides capabilities in the L and M bands in longslit and LR-IFU modes, is anticipated to be available in shared risk.

Visiting instruments offered in 2026B (subject to demand) are:

  • 'Alopeke: A dual-channel fast-readout visual-wavelength camera giving simultaneous diffraction-limited images (via speckle reconstruction) in two filters over a 2.8 arcsec field of view; as well as a wide-field mode which provides simultaneous two-color, non-speckle imaging in standard SDSS filters over a 60" field of view. The scheduling and length of the 'Alopeke visiting block(s) will be subject to demand. ‘Alopeke may also be available outside those blocks on a best-efforts basis. Targets of Opportunity (Rapid or Standard) are accepted for 'Alopeke, but will only be executed during the instrument blocks.

  • MAROON-X: A high-resolution (R~80,000), optical (500 - 900nm) radial velocity (RV) spectrometer,  is open to the community for high precision RV studies as well as general purpose high-resolution spectroscopy. Available during specific blocks, subject to RA demand. Please use the MAROON-X Exposure Time Calculator to evaluate the instrument performance. It is now also possible to check for MAROON-X target duplication: please see the instructions in the Phase I checklist.

Gemini South:


Targets are generally limited to 16 < RA hours < 12 and -90° < dec < +28°. Additional constraints are described in the target accessibility and instrument restrictions page of this Call for Proposals. Note that the RA ranges with limited accessibility near the start and end of the semester are typically in very high demand, and so prospective PIs may wish to consider avoiding targets with these RAs, where possible.

Facility instruments offered in 2026B are:

  • GHOST : A high-resolution optical spectrograph (383–1,000 nm) delivers R~56,000 (standard-res) and R~76,000 (high-res). In 2026B, GHOST is offered in both modes, as well as for non-sidereal targets and faint objects requiring blind offsets. The precision radial velocity mode (with simultaneous calibration) is not offered. Potential users should check for updates on the GHOST web pages for further details and status updates.

Visiting instruments offered in 2026B (subject to demand) are:

  • Zorro : A dual-channel fast-readout visual-wavelength camera giving simultaneous diffraction-limited images (via speckle reconstruction) in two filters over a 2.8 arcsec field of view; as well as a wide-field mode which provides simultaneous two-color, non-speckle imaging in standard SDSS filters over a 60" field of view. The scheduling and length of the Zorro visiting block(s) will be subject to demand. Targets of Opportunity (Rapid or Standard) are accepted for Zorro, but will only be executed during the instrument blocks.

Visiting Instruments not available in 26B:

  • IQUEYE .  The instrument uses an interferometric approach, combining light from multiple small sub-apertures to achieve high-resolution imaging (in the milliarcsecond range). Observing run is already done (25A). Depending on the performance of the instrument and the quality of the data produced, the IQUEYE PI will decide whether to request a return visit. If they do, the instrument will be offered to the community.

Subaru Exchange Time:

The exchange of time between the Gemini and Subaru communities will continue in 2026B; around 5 nights are expected to be available on Subaru for the Gemini community via the exchange program. Subaru exchange time is open to all Gemini partners, including Chile. A summary of the Subaru capabilities in 2026B is given below. PIs should also consult the Subaru Call for Proposals .

In addition, the Gemini community can propose shorter programs for Subaru's Service mode. PIs must indicate on the proposal whether regular or service time is requested. Service programs must be short programs of less than 4 hours duration, including calibration and overheads, using one of IRCS , HDS , FOCAS or MOIRCS . Up to 1 night is expected to be available in this mode for the Gemini community. Prospective investigators must carefully review the Service Program web page . In particular, some additional, detailed technical information must be provided at the time of Phase-1 submission. Service proposals are reviewed by the National TACs together with the regular proposals.

Details:

  • Duplicate Subaru proposals submitted via other routes: If eligible PIs submit a proposal for Gemini Subaru exchange time and also submit the same proposal to a different TAC in parallel (e.g. researchers via the open use time offered in the Subaru Call, Gemini community PIs via the Gemini time-exchange program or Keck community PIs via the Keck time-exchange program), the proposers are asked to explicitly note the double submission in the proposal.

  • Proposal submission: Proposals for time on Subaru via the Gemini time-exchange program are submitted via the normal Gemini Phase I process.

  • HSC/PFS queue proposal length limits: For semester 26B, Gemini users can request no more than 3.5 nights (35 hours science time including overheads) in the case of HSC/PFS queue, and no more than 5.0 nights in the case of HSC classical requests.

  • Subaru Strategic Programs (SSP): In S26B, PFS-SSP will be assigned about ~10-15 nights over 2 observing runs. IRD-SSP was completed in S25B.

  • Rapid and Non-rapid ToO Programs: There are two types of ToO programs: Non-rapid ToO programs do not require immediate attention and can be executed after 24 hours or more. PIs need to submit their requests by 9:00 am Hawaii time one day before their observing night. Rapid Too programs require immediate attention and need to be executed within 24 hours. PIs can submit their requests within 24 hours. Considering the practical approval procedure, we recommend that PIs trigger several hours before the observation.

  • Deformable Mirror (DM) upgrade for AO188 : As part of the AO3k project , the DM has been upgraded from a 188-element bimorph mirror to a 3228-actuator magnetic mirror. AO188 provides three modes:

    • NGS/ AO188 mode: Uses the 188-element Wave Front Sensor (WFS) + 3k-element DM);

    • LGS/ AO188 mode: Uses the 188-element WFS + 3k-element DM;

    • NIRWFS/AO3k mode: Uses the NIR WFS + 3k-element DM.

While the NIR WFS provides high-performance AO correction, NGS and LGS mode performance is unchanged because they use 188-element WFS. Please consult the AO3k web page for more information.

  • Instrument switches during the night: Switching between IRD , REACH , CHARIS , VAMPIRES and Fast PDI during a single or half-night observation is possible. Please check the Subaru Call for Proposals for the time required for switching instruments.

  • Subaru telescope / instrument downtime:

    • Downtime for the S26B period is expected to be about 2.5 months. (1)Main shutter control panel refurbishment will require six nights on two separate three-night occasions, scheduled for October and December. (2) Replacement of the AZ and EL incremental encoders will take approximately 16 weeks, spanning mid-November to February.

    • Nasmyth Beam Switcher (NBS): The NBS can be used for all IRCS, SCExAO, and REACH observations in shared-risk mode. For more information about the potential effects of the NBS, please visit the IRCS and SCExAO webpage(s).

  • Subaru instrument and telescope restrictions:

    • The LGS system for AO188 will be operated with TBAD. Please check the AO188 webpage for the latest information. Please prepare for the NGS mode observation as a backup for when LGS performance issues are still standing. Please note that IRD will not be available in LGS-AO188 mode in S26B.

    • The windscreen of the Subaru telescope is out of operation in 2026B, and thus tracking of targets may not be possible in high winds. It is recommended that PIs have targets across a range of RAs so that different azimuth angles are available.

Facility instruments offered in 2026B:

  • Hyper Suprime-Cam (HSC - very wide field optical to far-red imager) : There will be at most two (2) or three (3) HSC observing runs in the S26B semester, depending on the number of PFS commissioning runs (see below) as well as the timing of the facility maintenance works. Note that some filters require permission from the PI of the filters. All applicants must explicitly describe the filters they intend to use, in their proposal. The desired set as well as the minimum acceptable set should be clearly specified. Please check the HSC website for full details.

  • IRCS (infrared camera and spectrometer, with AO188 capability) is available. Please note that LGS-AO mode will be operated with TBAD in a shared-risk policy. All proposals requesting LGS mode observation should prepare a backup plan with NGS Mode. Prospective PIs should check the filter availability for the instrument before submitting a proposal. The polarimetry mode is a shared-risk mode, accessible via collaboration with the waveplate PI.

Visiting instruments offered in 2026B, are listed below. Proposals to use visiting instruments must include the instrument PIs as Co-investigators. Visiting instruments may be used in intensive programs if necessary conditions are fulfilled. Please check the Intensive webpage .

  • CHARIS : NGS-AO188 or NIRWFS-AO3k with SCExAO (including spectropolarimetric mode): Coronagraphic High Angular Resolution Imaging Spectrograph - provides high contrast images of exoplanets, disks, brown dwarfs with SCExAO .

  • Fast PDI : NGS-AO188 or NIRWFS-AO3k mode with SCExAO (in shared-risk mode). Polarization differential imaging (PDI) with a high speed (>kHz) near-IR (950 - 1860 nm) low-noise camera (C-RED One), optimized for high contrast imaging of circumstellar disks with SCExAO + AO188 .

  • IRD - Infrared Doppler : NGS-AO188 mode. infrared high-dispersion, high resolution (up to 70,000) fiber-fed spectrometer. The IRD SSP (Subaru Strategic Program) was started in 2019A – any IRD proposal must clarify how its scientific aim is different from the SSP. The observing mode REACH (SCExAO + IRD) , is available (see below).

  • REACH (combination of SCExAO and IRD for single-mode fiber spectroscopy): REACH can be used simultaneously with CHARIS with any dispersion modes, but the wavelength coverage of CHARIS will be from 1850 nm to the longest wavelengths (please see the CHARIS website for details).

  • VAMPIRES : NGS-AO188 or NIRWFS-AO3k mode with SCExAO (cameras have been upgraded for improved sensitivity, speed, and dynamic range. A new multi-band imaging mode is available.). The Visible Aperture Masking Polarimetric Imager for Resolved Exoplanetary Structures (VAMPIRES) is a visible light instrument on the SCExAO system. Cameras have been upgraded for improved sensitivity, speed and dynamic range. A new multi-band imaging mode is available.

  • NsIR Wave Plate Unit : A visiting device for IRCS / SCExAO polarimetry mode.

  • NIR WFS : Near Infrared Wavefront Sensor. Located inside the AO188 instead of the visible curvature wavefront sensor of AO188 for SCExAO and IRCS .

  • FIRST-PL : NIRWFS-Ao3k mode with SCExAO .

The laser guide star (LGS) system can be used with IRD under shared-risk mode. CHARIS , Fast PDI and VAMPIRES can be used together at the same time as the modules of SCExAO (Subaru Coronagraphic extreme Adaptive Optics). Please check the relevant instrument web pages for the latest information.

Other Proposal Opportunities in 2026B

Other proposal opportunities are available at Gemini Observatory in 2026B. These include:

  • The Fast Turnaround (FT) Program provides monthly opportunities to submit proposals, with successful programs scheduled for observation starting one month after each proposal deadline. Up to 10% of the time at Gemini North and Gemini South is available for FT programs. PIs must be members of the Argentina, Brazil, Canada, Korea, United States or Subaru astronomy communities. The University of Hawaii and Chile do not take part in the FT program and therefore UH and Chilean PIs do not have access to FT time.

  • Poor Weather Proposals are solicited for programs that can use poor, but usable, conditions and are executed when nothing in the regular queue is observable. Proposals can be submitted via the normal TAC process (this call) or at any time. PIs must be based in Gemini participating countries or the host institutions.

  • The Gemini community is eligible to propose HyperSuprimeCam (HSC) filler programs on Subaru without a time exchange cost. Filler programs are executed in poor observing conditions (typically seeing >1.5 arcseconds, and/or poor transparency) and up to 35 hours can be requested by a filler proposal, although the first 4 hours have priority. Execution is not guaranteed: observations are made only when there is no other program in the HSC queue. In recent semesters, typically ~15% of HSC time has gone to filler programs.  Proposals must be sent through the Subaru submission system (NOT Gemini), and are considered only by the Subaru TAC. Note that only a short text summary of the program is required, not a full detailed Science Justification.

  • The Gemini community has the opportunity to propose Subaru Intensive Program programs as LLP proposals, which request more than 5 nights in classical mode and 3.5 nights for the HSC/PFS queue mode.

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