The following capabilities and announcements are notable for the 2023B 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 2023B must use the 2023B Phase 1 template. The template has been designed to enable the anonymous review process, and to make proposals requirements, such as page and figure limits, uniform across the partners.


• Classical mode observing is offered in semester 2023B for facility instruments only. 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. PIs requesting Classical observing 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 23B.


• Both Gemini North and Gemini South expect to have engineering shutdown periods during the 2023B semester: Gemini North: Oct 30 - Nov 03, 2023; Gemini South: Sep 25 - Oct 24, 2023. These dates are provisional, and may be subject to change in the event of unforeseen circumstances.

Facility Instruments:

• GMOS North is now available with a B480 grating.
• GMOS South is expected to be available with a replaced detector from June 2023 onwards, but prospective PIs should check the instrument web pages for updates on availability.
• At Gemini North, Altair NGS and LGS+P1 (super-seeing) modes are fully functional. However, there is currently a technical issue with LGS mode, a resolution for which is being worked on, and this could impact the availability of GN LGS in the 2023B semester. Prospective LGS PIs should check the instrument web page for updates.

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 2023B.
• 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 2023B. 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 2023B. 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 17 < RA hours < 13.5 and -37 < DEC degrees < +90. The telescope is expected to not be available between October 30 and November 3, 2023, for maintenance of the Acquisition and Guider unit. There are additional constraints as described in the target accessibility and instrument restrictions page.

Facility instruments offered in 2023B are:

• Altair AO system: NGS and LGS+P1 (super-seeing) modes are fully functional. However, there is currently a technical issue with LGS mode, a resolution for which is being worked on, and this could impact the availability of GN LGS in the 2023B semester. Prospective PIs should check the instrument web page for updates.

• GMOS North (0.36-1.03 micron imager and spectrometer): available throughout the semester. The new B480 grating is available. The R600 grating is not available.

• GNIRS (1-5 micron spectrometer): available with or without AO capability. As before, the short red camera is NOT available. YJHK imaging is available via the acquisition keyhole. The two new GNIRS IFUs are currently undergoing commissioning in 2023, and so 2023B proposals requiring IFU use should request NIFS (below).

• 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. It is anticipated that commissioning of the GNIRS IFUs will be completed in 2023, in which case 2023B is expected to be the last semester for which NIFS will be offered.

• Not offered in 23B for new programs: NIRI. For proposals involving YJHK imaging, please see GNIRS (above) instead.

Visiting instruments offered in 2023B 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.

• 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 23B for new programs: GRACES, TEXES, POLISH-2.

Targets are generally limited to 16 < RA hours < 12 and -90° < dec < +28°. Due to the shutdown (September 25 - October 24), the time available at RAs between 20 hours and 6 hours will be reduced by 20% to 30% and so investigators with targets in this range are advised to have alternative targets available. There are additional constraints as described in the target accessibility and instrument restrictions page.

Facility instruments offered in 2023B are:

• GMOS South (0.36-1.03 micron imager and spectrometer): Expected to be available with a replaced detector from June 2023 onwards. Prospective PIs should check the instrument web pages for updates on availability.

• FLAMINGOS-2 (0.9-2.4 micron wide-field imager and spectrometer): offered in imaging, long-slit and MOS modes throughout the semester.

• 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.

• Not offered for new proposals at this time: GHOST. A limited Special Call for Proposals exclusively for GHOST is currently planned for late 2023.

Visiting instruments offered in 2023B (subject to demand) 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 2023B; 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 2023B 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 (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 informationn 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:

• 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. 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), the proposers should 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.
• 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: There will be 1-2 weeks of downtime (most likely in November and January) to replace the telescope chillers.
• Subaru instrument downtime:
  • The laser guide star (LGS) system for AO188 will be operated with TBAD (Transponder Based Aircraft Detector) with a shared-risk policy.
  • TUE2 repair work: TUE2 (Top-Unit-Exchange 2) repair work is planned from October 11, 2023 to January 5, 2024. During this period, 1) only an IR secondary mirror will be available. 2) HSC and FOCAS will NOT be available. 3) HDS observation is limited to V < 17 mag and WL > 3500 A.
  • The windscreen of the Subaru telescope is out of operation in 2023B, and thus tracking of target 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 2023B:

• AO188 (Subaru 188-elements Adaptive Optics system) is available in Natural Guide Star mode, LGS-AO mode will be operated with TBAD as a shared-risk mode only.

• FOCAS (optical camera and spectrograph) is available.

• HDS (optical high dispersion spectrometer) is available.

• MOIRCS (Multi-Object Infrared Camera and Spectrograph) is available (possibly on a shared-risk basis).

• Hyper Suprime-Cam (HSC - very wide field optical to far-red imager) is available. New filters are available, however applicants must obtain prior approval for their use. 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.
  • There will be at most two or three HSC observing runs in August, September, and January.
  • No HSC run is planned at least between October and December due to engineering work (Top Unit Exchanger overhaul).

• IRCS (infrared camera and spectrometer) is available with Natural Guide Star Adaptive Optics capability. In addition, the IRCS LGS+AO mode is available as a shared-risk mode. The IRCS/SCExAO polarimetry mode is also available as shared-risk mode.

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

• CHARIS: Coronagraphic High Angular Resolution Imaging Spectrograph - provides high contrast images of exoplanets, disks, brown dwarfs 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 new laser guide star (LGS) system can be used with IRD in shared-risk mode.
• 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.
• REACH (IRD+SCExAO+AO188) is available. REACH ("Rigorous Exoplanetary Atmosphere Characterization with High dispersion coronography) connects the high-contrast instrument (SCExAO) to the high-resolution IR spectrograph (IRD) at the Subaru Telescope.
• VAMPIRES : The Visible Aperture Masking Polarimetric Imager for Resolved Exoplanetary Structures (VAMPIRES) is a visible light instrument on the SCExAO system. VAMPIRES cameras will be upgraded for improved sensitivity, speed and dynamic range. A new multi-band imaging mode will be available.
• NsIR Wave Plate Unit: a visiting device for IRCS/SCExAO polarimetry mode. This is only available via a shared-risk mode. Prospective users must contact the NsIR PI before proposal submission.