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.
  The KASI IGRINS team were awarded a compensatory time from Gemini, and in previous semesters, a good fraction of this time has been used for the IGRINS proposal from the community. However, for 2023B and onward, only small fraction of comp. time will be available to the community programs. Hence, most of the  IGRINS programs from the community will be allocated using the normal Gemini partner time of Korea.
• 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.
• GRACES, TEXES, POLISH-2 are not offered in 23B for new programs.

Subaru Exchange Time:

• 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.
• 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.
   

• Targets are generally limited to           
  • NORTH : 17 < RA hours < 13.5 and -37° < dec < +90° (Due to the shutdown (Oct 30 - Nov 3), the time available at RA 21 to 06 hours is reduced by about 20%. )
  • SOUTH : 16 < RA hours < 12 and -90° < dec < +28° (Due to the shutdown (Sep 25 - Oct 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.
   

• 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 which include the science and technical cases, and investigator information. The template has been revised to enable the anonymous review process, and to make proposals requirements uniform across the partners. Two attachments are required for the proposal so that team information can be separated from the science case.

• Additional options in the Time Requests module in the PIT are available for semester 2023B:
  - The Gemini 2023B Phase 1 Tool includes options to specify that the proposal is for the Aeon multi-telescope-facility system. 
  - Also in the 2023B 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.  More information is available here.