This page provides best estimates, at the time of the Call for Proposals, of instrument restrictions and target (RA, DEC) accessibility for 2023A.

All instruments are restricted for sky visibility as described in the Table below. In addition:

• Observations using the Gemini North laser guide star (LGS) system are restricted to greater than 40 degrees elevation. How this translates into RA and DEC restrictions is indicated in the below Table.
• Altair  Altair is available in Natural Guide Star and Laser Guide Star mode in semester 2023A.
• MAROON-X, NIFS and NIRI may share the bottom port of the telescope and will be block scheduled. We expect that each instrument will be scheduled for two or three approximately month-long observing blocks. This pressure means instruments may not be scheduled during the semester, or may be scheduled for limited periods of time. Investigators with time-critical observations using NIFS, NIRI or MAROON-X should specify both ideal dates and frequency for their observations, as well as less-preferred dates or sampling frequency.

^**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.

All instruments are restricted for sky visibility as described in the Table below. In addition:

• A shutdown is planned for the last three weeks of April, 2023, i.e. April 10 - 30. , in order to execute the delayed primary mirror coating at Gemini South. 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%.
• GMOS South (0.36-1.03 micron imager and spectrometer): The noise problem on CCD-2 persists, as of August 2022; and 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 during those dates, 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.
• FLAMINGOS-2 (0.9-2.4 micron wide-field imager and spectrometer) will be offered in imaging, long-slit and MOS modes throughout the semester. The multi-object spectroscopy (MOS) mode allows the simultaneous observation of up to 150 targets per mask over an area of 6’x2’.
• Observations using GeMS are restricted to greater than 45 degrees elevation. How this translates into RA and DEC restrictions is indicated in the below Table. The expectation is to have two or three laser runs of 7 nights, therefore up to about 150 hours will be scheduled at ITAC (Queue only, Bands 1 & 2 with IQ70&IQ85).
• Due to greater-than-average, repeatable, weather loss in May, June and July at Gemini South, the availability of time in the RA 16h - 20h range has been reduced by 10%, RA 20h - 22h by 18%, and RA 23h - 2h by 25%.
• Zorro and IGRINS will be available in Semester 2023A.  Scheduling of these instruments will be driven by the demand.

^**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.