• 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) has been 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  • Unpublished work can be referred to as “obtained in private communication” or “from private consultation”.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 Project Office will check the flagged proposals and send any violations to the KGO for review.)

The following capabilities and announcements are notable for the 2027A semester. Please see the relevant instrument pages and subsections of this Call for Proposals for details.

• All proposals to use Gemini in 2027A must use the 2027A 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 2027A 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 27A.

• 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.

• Rapid ToOs will be accepted at all times, using any instrument mounted on the telescope.

• Reduced Data Products for GMOS PIs: Reduced long-slit and imaging data will be offered by Gemini for GMOS programs. These reduced data products, alongside the raw data, will be accessible via the Gemini Observatory Archive.

• Gemini North Engineering Time: Shutdown time for A&G maintenance tasks will require 18 days. The anticipated dates are between April 12 - 29, 2027. These dates are provisional and may be subject to change. The back to sky checks for all instruments will be performed beginning on April 29. The 27A shutdown will limit the availability of targets that are observable at RA 13 - 16 hours, and alternative targets should be prepared.

• Gemini North - This Semester, Gemini North is pre-scheduling instruments on the bottom (up-looking) port. 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. Both IGRINS-2 and Maroon-X will be operated as part of the multi-instrument queue while they are on the telescope.

• IGRINS-2 PIs to receive reduced data products: Gemini, will offer reduced spectra for IGRINS-2 programs. The reduced files will be generally produced on the day following the observations and will be made available through the Gemini Observatory Archive, together with the raw data.

• Gemini South Engineering Time. Shutdown time for A&G maintenance tasks will require 12 days in 27A. The anticipated dates are between July 19 - 31, 2027. These dates are provisional and may be subject to change. The back to sky checks for all instruments will be performed after the first week of 27B, when the shutdown is expected to finalize.

• IQUEYE is offered on Gemini South in 27A, and will be available in specific blocks depending on approved programs.

• SCORPIO. Gemini South’s new multi-channel imager and long-slit spectrograph will be commissioned during semester 2027A in four seven-night blocks. Later in the semester, standard imaging and long-slit spectroscopy with SCORPIO’s four visible channels will be offered to the community on a shared-risk basis. All four channels will operate simultaneously over a 180″×180″ field of view at a pixel scale of 0.18″/pixel. This capability will provide four-band imaging (g, r, i, and z) or medium-resolution (R~4000) spectroscopy from 385 to 960 nm in a single exposure. Further details, including the available observing time, observing constraints, and proposal schedule, will be announced in a dedicated System Verification Call for Proposals.

• Gemini South - GHOST PIs to receive reduced data products: 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.

• Preparing for the Gemini Program Platform (GPP). We are expecting to use the new Gemini Program Platform (GPP) for the 2027B call for proposals. 

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 penalized. 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 who has the relevant partner affiliation.

Band 3 targets and conditions: For PIs with programs that want to be considered for Band 3, in addition to selecting the option in the PIT, we strongly recommend setting the appropriate weather conditions and adjusting the exposure times accordingly, following the guidelines described here.

Specific Timing Windows: In order to maximize the chances of completing observations with timing windows, 27A 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: 2026-11-08 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 2027A:

• The Gemini 2027A Phase 1 Tool includes options to specify that the proposal is for the AEON multi-telescope-facility system.

• Also in the 2027A 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.

Gemini North:

** 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:

** 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.

Gemini North:

Gemini South: