Keck Call & Proposal Instructions

Latest Keck Call for Proposals
Call for Proposals: UC time on the Keck telescopes
Semester 2023A (Feb. 1, 2023 through Jul 31, 2023)
Deadline: Proposals are due on Thursday, Sept. 22, 2023 by 5:00pm PDT
1.1 Due Date

Proposals for UC observing time on the Keck Telescopes for Semester 2023A are due by 5:00 pm PDT on Thursday, Sept 22nd, 2022.  There will be 56.0 nights available on K1 and 55.0 nights available on K2 spread evenly across the semester and lunar phase.  There are 7 one-hour Partnership ToO interrupts available.  A PI may ask for a larger number of UC-time only ToO interrupts as well.   
1.2 Proposal Process
NOTE:   In normal (non-LMAP) proposals PIs will now have to report if they are any key LMAP members included in the LMAP management plan.
The principal consideration in evaluating proposals will be the scientific merit of the proposed project. Projects that take maximum advantage of the unique capabilities of the Keck Telescopes will be given high weight. A brief description should be given of backup programs that will be carried out if conditions are not suitable for the primary program. Please see which describes the UC online proposal submission process, and which describes the required sections and their page limits. The Time Allocation Committees take page limits very seriously, so please pay close attention as you draft your proposal. 
Keck is continuing the login-password system to allow you to retrieve and modify your coversheets. Returning observers should use the same account information as last semester. New observers may request an account from the page 
The coversheet form is available through the login page link above. Once you have created a coversheet and you are logged in, please go to the instructions for submitting Keck proposals at: to create the rest of your proposal as a PDF file to upload to the UC proposal server. Note that the coversheet has been modified again this semester, so please pay close attention when filling it out. 
You may use the extra page allocated to the project update if this is a resubmission to respond to the previous TAC comments, even if the previous submission was unsuccessful.  It would be useful to mention the previous proposal title (if different), PI (if different) and proposal number.    
1.3 Be Kind to your TAC Members 
Please read the page limits carefully on the keck-guidelines web page ( and adhere to them. TAC members will be instructed to stop reading any text beyond the stated page limits. Note that the text format is 12 point font; single-spaced; one-inch margins. 
Although there is not a formal limit on the number of Keck proposals that one PI can submit, experience has shown that TAC members view one PI submitting numerous proposals as a real burden on the reviewing process; it generally does not increase the odds of a PI getting Keck time. Please use moderation. 
1.4 Time Domain Astronomy (TDA)
Observers will continue to have the ability to propose both Target of Opportunity (ToO) and Cadence programs using the Keck Cover Sheet. Keck policies related to Target of Opportunity (ToO) and Cadence proposals can be found at and
If your project involves both Classical and TDA observing, you MUST put in two separate cover sheets so that the Keck TDA software can clearly distinguish between the two. Instead of submitting the same text twice, please submit the actual proposal text under the Classical cover sheet; the text submitted under the TDA (ToO or Cadence) cover sheet should merely include the proposal title, PI, and proposal number, together with a sentence stating that the main text can be found under the proposal number of the Classical cover sheet. The Cover Sheet form will not let you submit one proposal requesting both Classical and TDA observing time. 
For Semester 2023A, two types of ToO requests can be made.  TAC- approved ToO projects which are able to interrupt observers at any of the four institutions, to increase the utility of the ToO process. These are called Partnership ToO proposals. There is a limit to the number of Partnership ToO interrupts.   The second kind of TAC approved ToO program (Institutional) can only interrupt UC programs.   Note that there is not a limit to the number of “Institutional” ToO interrupts of fellow UC observers. But because UC nights are only a fraction of the total available Keck nights, the probability of a successful ToO interrupt using UC time alone is smaller than for Partnership ToOs. Also note that UC Institutional ToO time can be interrupted by a Partnership ToO, so think through your strategy carefully.   Both Partnership and Institutional ToO interrupts are counted in full 1 hour increments even if less than 1 hour of time is used.  All ToO proposal requests should be made in units of 1 hour interrupts.
In 2023A, partial-night observations can be interrupted. The Keck guidelines state that “Individual TACs may designate a few nights (partial or whole) as exempt from ToO interrupts. This designation must be scientifically motivated, namely that such interruptions would seriously compromise the scientific return of the entire observing time. Proposers should make any such requests to their individual TACs as part of their observing proposal. Use of these exemptions is expected to be rare.” So if you think your project deserves, for scientific reasons, to have one of these rare exemptions from interruptions, please state so in your proposal and give a very strong justification for your request. 
1.5 Cadence Observations 
Keck’s policies for Cadence observing ( are reasonably complicated. These include a new category called “Partnership Snapshot” observatories. If you are contemplating applying for Cadence time, please read the guidelines carefully. 
Keck continues to reconcile cross-institutional cadence and ToO allocations. Scheduled cadence time is returned to the institution at a one to one rate, and ToO time is returned at a rate of two hours for every one hour interruption because the ToO PI will not choose to call for a trigger if the weather is unacceptable. 
1.6  Twilight Cadence Observations
In 2023A, institutions will continue to be able to allocate one twilight observing program per telescope, for a total of up to two programs.  On Keck I, OSIRIS-NGS (imager only) will be available, and on Keck II, NIRC2-NGS will be available.  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.
1.7 Large Multi-Year Projects 
UC LMAP observing projects with well-defined scientific objectives that require a large number of nights to bring to completion (normally 10 or more nights per semester). The UC LMAP program allows projects extending for more than one semester to be carried out with multi-year approval from the beginning. LMAPs should generally be directed toward obtaining a high quality, coherent, homogeneous data set that will allow scientific questions of major importance to be addressed in a thorough, systematic manner. Please consult for current policies regarding LMAPs. 
1.8 At-Home (pajama mode) Observing
  • At-Home observing will continue to be available to observers
  • At home observing requires the installation of software which only runs on linux and macOS operating systems. 
  • Observers using at home observing should plan to work with Keck staff to install and test the software several days ahead of their run to allow time for troubleshooting.
2.0 Notes on Instruments and Availability 
See the following web page for detailed notes on the availability of instruments for 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. 
KCWI:  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. 
KPF: 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 made available and linked on the ‘Instruments Available’ webpage within the next two weeks. 
NIRSPEC/NIRSPAO:  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.
  • The vortex coronagraph in LGS mode is not available.
  •  The vortex coronagraph with the PyWFS is not available.
Please, see the NIRC2 manual ( for information about vortex operations.
SUBARU exchange:  The SUBARU-KECK exchange will continue as in previous semesters with flexibility as to the number of nights available for exchange. The number of exchanged nights will be determined based on the demand from each community.  Keck will offer LRIS, HIRES, OSIRIS, and MOSFIRE on Keck I, and DEIMOS, ESI, NIRSPEC/NIRSPAO, NIRES, and NIRC2 on Keck II.   Subaru will offer facility instruments Hyper Suprime-Cam (HSC), HDS, IRCS (with NGSAO only, see below), MOIRCS, and FOCAS, as well as visiting instruments IRD,  CHARIS + SCExAO, VAMPIRES, REACH, Fast PDI, MEC, and NsIR.  Note that PIs must contact the instrument PI for visiting instruments in advance.  Subaru may support half night allocations, but whole night allocations are preferred.   Queue observing is the default observing mode for HSC; applicants who desire classical mode must justify their request. Please check the HSC queue mode website for more details.   
Notes regarding Subaru facility and instrument availability in 23A:
  • 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.
  • 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.
  • 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.
  • New LGS+AO188 mode will be available with shared-risk status
  • 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
  • CHARIS with SCExAO+AO188 (including spectro-polarimetric mode)
  • Fast PDI with SCExAO+AO188 (in a shared-risk mode)
  • IRD with AO188 (in a shared-risk mode)
  • MEC with SCExAO+AO188 (in a shared-risk mode)
  • REACH (combination of SCExAO and IRD for single-mode fiber spectroscopy)
  • VAMPIRES with SCExAO+AO188
  • NsIR Wave Plate Unit (a visiting device for IRCS/SCExAO polarimetry mode)
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).
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.

Instructions for Submitting Keck Proposals

1. Proceed to the Keck Observer Login Page. Login using an existing Keck observer account (or, if necessary, create a new account and login). Find the Cover Sheets section and submit a new Cover Sheet, or select an existing Keck Cover Sheet to be updated and re-used. Follow the instructions to prepare and submit the Keck Proposal Cover Sheet.

The “Allocating Institution” should be one of the UC options (in order to send the Cover Sheet to the UCO web server). Please ensure that the e-mail addresses of the PI and all Co-Is are valid; this is important for subsequent processing of the proposal by the UCO web server.

Take note of the Keck Cover Sheet Id that is assigned for the proposal.

After submission at Keck there is a delay, typically of some minutes, while the Cover Sheet is transferred from the Keck web server to the UCO web server for the next steps. The UCO web server can only accept proposals after it receives the Cover Sheet from Keck, so be sure to do this step before the deadline.

2. Prepare the body of the proposal containing the Scientific Justification, figures, Technical Comments, Results from Previous Keck Runs. Please see the UC Keck Proposal Guidelines for the full set of instructions.

The top line of the proposal must contain the PI name, the assigned Keck Cover Sheet Id, and proposal title.

This proposal must be a PDF file.

3. Go to the UC Keck Proposal web page.

Enter the e-mail address of the PI (or a Co-I) as listed on the Keck Cover Sheet, the Keck Cover Sheet Id, and click the “Proposer Login” button.

Click the “Submit (or resubmit) a TAC Proposal File” button. Use the web browser file chooser to select the PDF file with the proposal that is on the local machine running the browser. The submission web page will give an opportunity to review the PDF file that has just been uploaded.

Note: The UCO web server will accept multiple revisions of the proposal PDF file until the deadline; simply return to the web page and submit the new version. The Keck web server will accept edits to modify an existing Cover Sheet; that will preserve the Cover Sheet Id and the connection with the proposal submitted to the UCO web server. The instructions for this are found at the Keck Observer Account web pages. (If a new Cover Sheet Id is created at Keck then the UC web server must receive a proposal for that new Cover Sheet Id.)

4. After the proposal has been uploaded to the UCO web server it will send e-mail confirmation to the PI and all Co-Is listed on the Keck Cover Sheet. Please watch for this confirmation.

If you have any issues with the Keck CoverSheet please contact

If you have any technical problems with the proposal software please contact

If you have questions about policy, procedure or suggestions for improving the proposal system please contact Deputy Director Matthew Shetrone.