The following capabilities and announcements are notable for the 2023A semester. Please see the relevant instrument pages and subsections of the call for proposals for details.

General:

• All Gemini proposals requesting time from the US, CA, BR, 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 which include any of these partners. This requirement applies whether it is the PI or a co-I that has the relevant partner affiliation.


• All proposals to use Gemini in 2023A must use the Phase 1 template, which was revised in 22B to enable anonymous reviews, and to make proposals requirements, such as page and figure limits, uniform across the partners. Two attachments are required for the proposal so that team information can be separated from the science case.


• Starting in 22B, the Gemini Phase 1 Tool includes an option to specify that the Gemini proposal is part of the AEON multi-telescope-facility system, and an option to identify proposals which have synergies with James Webb Space Telescope observations, whether already awarded, or still to be proposed.


• Classical mode observing is NOT offered in semester 2023A. Priority Visitor mode is offered at both Gemini North and Gemini South; however if circumstances preclude having people on site, then awarded Priority Visitor time will revert to queue. The "Bring One, Get One" Student Observer Support Program remains unavailable.

Facility Instruments:

• NEW for 2023A - GMOS South is now available with a B480 grating. This grating is not yet installed in GMOS North.

Visiting Instruments:

• 'Alopeke and Zorro, the fast low-noise dual-channel and dual-plate-scale imagers with speckle and wide-field modes, will be available for science as resident visiting instruments at Gemini North and Gemini South, respectively, in 2023A.
• IGRINS, a high-resolution (R~45000), single-setting, near IR (1.45 - 2.5 microns) echelle spectrometer, will be available for science as a visiting instrument at Gemini South in 2023A. See the IGRINS at Gemini page for information on how to determine exposure times.
• MAROON-X, a high-resolution (R~80,000), optical (500 - 900nm) radial velocity (RV) spectrometer, will be available for science  as a visiting instrument at Gemini North in 2023A. The instrument is open to the community for high precision RV studies as well as general purpose high resolution spectroscopy. The instrument has demonstrated sub-m/s on-sky precision for RV measurements of M dwarfs, although the instrument performance is continually being assessed and improved. Please use the Maroon-X Exposure Time Calculator to evaluate the instrument performance.

Targets are generally limited to 4 < RA hours < 1 and -37 < DEC degrees < +90. There are additional constraints as described in the target accessibility and instrument restrictions page.

Facility instruments offered in 2023A are:

• GMOS North (0.36-1.03 micron imager and spectrometer): available throughout the semester. The R600 grating is not available.

• GNIRS (1-5 micron spectrometer): As before, the short red camera is NOT available. YJHK imaging is available via the acquisition keyhole. A new low-resolution IFUs is being commissioned and will be offered for Fast Turnaround proposals only in semester 2023A.

• NIFS (0.95-2.40 micron integral field unit spectrometer): available with or without AO capability. This instrument shares a port with NIRI and MAROON-X, hence it will only be available during specific blocks. NIFS is expected to be scheduled for two or three approximately one-month-long blocks during the semester. If the GNIRS IFUs are successfully commissioned in 2022, semester 2023A may be the last A semester where NIFS is offered.

• NIRI (1-5 micron imager): available throughout the semester. As in past semesters, NIRI is NOT available for spectroscopy. This instrument shares a port with NIFS and MAROON-X, hence it will only be available during specific blocks. NIRI  is expected to be scheduled for two or three approximately one-month-long blocks during the semester.

Visiting instruments offered in 2023A are:

• 'Alopeke: a dual-channel fast-readout visual-wavelength camera giving simultaneous diffraction-limited images in two filters over a 2.8 arcsec field of view; as well as a wide-field mode which provides simultaneous two-color 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 community demand.  Targets of Opportunity (Rapid or Standard) are accepted for Alopeke, but will only be executed during the instrument blocks.

• GRACES: a high-resolution, R~67,500, optical (0.4-1 micron) spectrometer. Scheduled blocks to be determined with CFHT (where the instrument resides), based on demand. Semester 2023A may be the last semester where GRACES is offered.

• 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.  Please use the Maroon-X Exposure Time Calculator to evaluate the instrument performance. This instrument shares a port with NIFS and NIRI, hence it will only be available during specific blocks. MAROON-X is expected to be scheduled for two or three approximately one-month-long blocks during the semester.

• Not offered in 23A: TEXES, POLISH-2.

Targets are generally limited to 5 < RA hours < 1 and -90° < dec < +28°. It is planned to execute the delayed primary mirror coating at Gemini South during the last three weeks of April, 2023. This date is a placeholder, and may change based on the progress of the coating preparations. If an April shutdown occurs, the time available at RAs 9 - 11 will be reduced by about 20%. There are additional constraints as described in the target accessibility and instrument restrictions page.

Facility instruments offered in 2023A are:

• GMOS South (0.36-1.03 micron imager and spectrometer): The noise problem on CCD-2 persists, as of August 2022; users are advised to dither or to place targets or spectral features on other parts of the detector. GMOS South may be removed for extensive engineering in the April to May 2023 period, to address this issue. In that case the instrument will not be available, and there will be reduced access to GMOS targets in the RA range of 8 to 12. Prospective users should check the instrument page for updates. The R600 grating is not available, however the new B480 grating is available, in 23A.

• FLAMINGOS-2 (0.9-2.4 micron wide-field imager and spectrometer): offered in imaging, long-slit and MOS modes throughout the semester. The multi-object spectroscopy (MOS) mode allows simultaneous observation of up to 150 targets per mask over an area of 6'x2'.

• GSAOI (0.9-2.4 micron adaptive optics imager) with the GeMS Adaptive Optics system: due to guide star limitations, investigators must check the availability of Guide Star constellations using the Observing Tool before submitting a proposal.  Observations in IQ85 are possible for programs that can use delivered images with full-width half-maximum of ~0.2 arcseconds as opposed to the ≤ 0.1 arcseconds delivered in IQ70 or IQ20 conditions. Observations under non-photometric conditions with 0.1 mag uniform extinction are also possible under very good IQ conditions.  The expectation is to have two or three laser runs of 7 nights each during the semester, the actual schedule will be based on the demand from the community.

Visiting instruments offered in 2023A are:

• Zorro: a dual-channel fast-readout visual-wavelength camera giving simultaneous diffraction-limited images in two filters over a 2.8 arcsec field of view; as well as a wide-field mode which provides simultaneous two-color 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 community demand.  Targets of Opportunity (Rapid or Standard) are accepted for Zorro, but will only be executed during the instrument blocks.

• IGRINS, a high-resolution (R~45000), single-setting, near IR (1.45 - 2.5 microns) echelle spectrometer, will be available throughout the semester except for two weeks before and during the 7-night GeMS/GSAOI runs. See the IGRINS at Gemini page for important information about writing IGRINS proposals.

The exchange of time between the Gemini and Subaru communities will continue in 2023A; around 5 nights are expected to be available on Subaru for the Gemini community via the exchange program. A summary of the Subaru capabilities in 2023A 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 FOCAS, IRCS(+AO), HDS, MOIRCS (imaging). Around 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.

Relevant information:

• Do NOT double-dip! PIs applying for time on the Subaru telescope must only apply via ONE of the following routes: Japanese researchers via the Subaru call; other 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. Duplicating your proposal across more than one of these committees will disqualify the proposal.
• Proposal submission: Proposals for time on Subaru via the Gemini time-exchange program are submitted via the normal Gemini Phase I process.
• Instrument switches during the night: Switching between IRD, REACH, CHARIS, VAMPIRES, Fast PDI, and MEC 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 downtime: the telescope will not be available for 1 to 3 days due to maintenance work on the electrical system. The dates will be announced later.

Facility instruments offered in 2023A:

• AO188 (Subaru 188-elements Adaptive Optics system) is available in Natural Guide Star mode and Laser Guide Star mode.

• FOCAS (optical camera and spectrograph) is available. 

• HDS (optical high dispersion spectrometer) is available.

• Hyper Suprime-Cam (HSC - very wide field optical to far-red imager) will have a maximum of four observing runs between March and June. Some filters require permission for use, prospective users should check the HSC web page. Important notice for HSC 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.

• MOIRCS (Multi-Object Infrared Camera and Spectrograph) back online in shared-risk mode.

• IRCS (infrared camera and spectrometer, with Natural and Laser Guide Star Adaptive Optics capability) is available. The polarimetry mode is a shared-risk mode.  PIs should check the filter availability for the instrument before submitting a proposal.

Visiting instruments offered in 2023A, are listed below. Proposals to use visiting instruments must include the instrument PIs as Co-investigators. 

• CHARIS: Coronagraphic High Angular Resolution Imaging Spectrograph, including spectro-polarimetric mode - with SCExAO.
• Fast PDI (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 (in shared-risk mode): infrared high-dispersion, high resolution (up to 70,000) fiber-fed spectrometer.  IRD SSP is started in 2019A – any IRD proposal must clarify how its scientific aim is different from SSP. The observing mode REACH (SCExAO+IRD), is available.
• MEC (in shared-risk mode): the MKID Exoplanet Camera is a near-IR (800-1400nm) photon-counting low-resolution (R~5) integral field spectrograph optimized for high contrast imaging with SCExAO+AO188.
• VAMPIRES : The Visible Aperture Masking Polarimetric Imager for Resolved Exoplanetary Structures (VAMPIRES) is a visible light instrument on the SCExAO system. 
• NsIR Wave Plate Unit: a visiting device for IRCS/SCExAO polarimetry mode.