Observing at WMKO

Instruments Available for Semester 2023A

For detailed information about the instruments, please check the Instruments Home Page
For information about which instruments can be used on the same night, please check Instrument Sharing
a Resolving Power vs. Wavelength comparison of Keck instruments, please check this Instrument Comparison graph.

Keck 1 Instruments are:

        HIRESb (blue x-disperser)
        HIRESr (red x-disperser)
        LRIS-ADC (red and blue, with ADC)
        LRISp-ADC (polarimeter, with ADC)
        KPF limited, shared-risk availability, see below


Keck 2 Instruments are:

        ESIi (ESI with the Integral Field Unit)
        KCWI limited availability, see below
        NIRSPEC (without AO) limited availability, see below
        NIRSPAO-NGS (NIRSPEC with Natural Guide Star AO, see restrictions below) limited availability, see below
        NIRSPAO-LGS (NIRSPEC with Laser Guide Star AO; see restrictions below) limited availability, see below
        NIRC2-PY (NIRC2-NGS with the Pyramid Wavefront Sensor) see restrictions below


Subaru Time Exchange Instruments are:

FOCAS, HDS, Hyper Suprime-Cam, IRCS, MOIRCS, CHARIS+SCExAO, VAMPIRES, REACH, MEC, Fast PDI, NsIR, and IRD. See below for limitations.

Telescope Limits

Please note that Keck I and Keck II have different eastern and western telescope limits. This affects the times objects will be available for observing. Objects can be acquired earlier on Keck II and followed later on Keck I.

Special Notes for Semester 2023A:

Keck I Telescope: There will be a 10 night shutdown occurring in late April bright time in order to conduct repair work on the Keck I telescope pier.

Update Oct 07, 2022 - Due to delays in the commissioning timeline, KCWI will not be available for use in 23A.
KCWI, with the red channel upgrade, KCRM, is expected to return to service in the May/June timeframe. Given the uncertainty in the commissioning schedule, updated availability information will be provided in October for TAC meetings and telescope scheduling. For more information on the red channel, please see https://www2.keck.hawaii.edu/inst/kcwi/configurations.html

Update Oct 07, 2022 - KPF remains on schedule. Shared risk science may begin as early as April, with Hires as a backup instrument.
Keck Planet Finder, a new PRV instrument on Keck I, is currently undergoing installation at the Observatory and is expected to become available for shared-risk use in the middle of the 23A semester. Updated availability information will be provided in October for TAC meetings and telescope scheduling. Documentation of KPF basic specifications will be updated as available on the KPF webpage.

NIRSPAO/NIRSPEC: Nirspec/Nirspao will be unavailable for 4 weeks in February for routine servicing to remove ice from the dewar window. Please also note that Nirspec and Nirspao nights may be scheduled in campaign mode to limit the number of reconfigs into AO during the semester.

KPIC: KPIC is not a fully commissioned instrument and is only available for shared-risk science in 23A in collaboration with and supported by the KPIC team.


Please see the NIRC2 manual https://www2.keck.hawaii.edu/inst/nirc2/ObserversManual.html#Section5.2.2 for information about vortex operations.

At-Home (pajama mode) Observing:

Time Domain Astronomy: Observers will continue to have the ability to propose both cadence and ToO programs using the cover sheet. Policies related to Target of Opportunity or Cadence proposals can be found at Too Policies and Cadence Policies. These policies are not applicable to Subaru Exchange time. TAC-approved Cross-institutional ToO (TDA) projects will continue to be able to interrupt observers at any Institution, to increase the utility of the ToO process.

Twilight Cadence Observing: The twilight cadence program will continue in 2023A, with NIRC2-NGS and OSIRIS-NGS available for use. Each institution may allocate one twilight cadence program per telescope. Please note that due to ongoing AO upgrades, there may be times in the semester when AO is unavailable for cadence observations. Cadence program PIs are responsible for development of instrument scripts, providing documentation, and training of staff needed to make the cadence program a turnkey operation. More details can be found in the Cadence Policy.

FOCAS, HDS, Hyper Suprime-Cam, IRCS, MOIRCS, CHARIS+SCExAO, REACH, FastPDI, MEC, VAMPIRES, NsIR and IRD will be available at Subaru. Please check the Subaru web site http://www.subarutelescope.org/Observing/index.html for detailed descriptions of these instruments. Please visit https://subarutelescope.org/Observing/Proposals/call.html for instrument restrictions, particularly for visiting (PI-type) instruments SCExAO+CHARIS, IRD, VAMPIRES, Fast PDI, MEC, REACH, and for filter availability of HSC. The SUBARU-KECK exchange will continue to have flexibility with regard to the number of nights available for exchange with the number of nights exchanged determined based on the demand from each community. In 23A, Subaru ToO observers will continue to be able to interrupt Keck observers on the Subaru Telescope, and Keck ToO observers will be able to interrupt Subaru observers on the Keck Telescope. Compensation will be according to the policy of each observatory.

Subaru observations are executed in "classical" observing mode, except for HSC observations. Queue observing is the default observing mode for HSC; applicants who desire classical mode with HSC must justify their request. For all classical observations, Subaru may support half night allocations, but whole night allocations are preferred. Please check the HSC queue mode website https://subarutelescope.org/Observing/queue/index.html for more details on HSC observations.

Subaru facility/instrument related restrictions for the 2023A semester:

  1. There will be 1-3 days downtime due to the scheduled maintenance work of the electrical system and the dome. The dates for downtime will be announced later.
  2. MOIRCS will be back online in 2023A with the shared-risk policy. SWIMS completed science operation at Subaru in S22B, and is not available any more.
  3. There will be 4 HSC runs in S23A at maximum from March to June. Note that some filters require permission from the PI of the filters. Please check the HSC website for details.
  4. New LGS+AO188 mode will be available with shared-risk status
  5. The following PI-type (visiting) instruments are available in S23A. Please be reminded that proposals requesting PI-type instruments/devices must include the relevant PIs as Co-I of the proposal (see https://www.naoj.org/Observing/Instruments/index.html ).
  6. One of the IRD detectors (YJ-band) has been unavailable from the beginning of January 2022. It might be still unavailable in S22B, depending on the progress of troubleshooting in Feb 2022. Please contact IRD team for more details.
  7. REACH can be used simultaneously with CHARIS with any dispersion modes, but the wavelength coverage of CHARIS will be from 1850nm to the longest wavelengths (please check the CHARIS website).
  8. Instrument switching between IRD, REACH, CHARIS, VAMPIRES, Fast PDI, and MEC during a single- or half-night observation is possible. Please check Subaru CfP for the time required for the switching the instruments.

LGS-AO: A detailed set of guidelines for LGS-AO nights and information on the capabilities of the systems may be found on the LGS-AO page. Backup programs for LGS proposals are essential. Backup programs for LGS on Keck II may be either NGS programs or NIRES. On Keck I, either NGS-OSIRIS and non-AO HIRES may serve as a backup.

KOA (Keck Observatory Archive): Data from all instruments will be archived in the Keck Observatory Archive (KOA). The default proprietary period for data is 18 months except for data taken with NASA as the allocating institution which has a default proprietary period of 12 months. If observers desire a different proprietary period they may request this through the Keck coversheet. Please see the KOA homepage for information on the archive. Please also see the KOA proprietary period policy.

For detailed information about the instruments, please check the Instruments Home Page

  (further observing information)

This page last updated 15 August 2022 ccj.