The JCMT operates on a two-semester basis for PI time. Semester A running from February 1st to July 31st and Semester B running from August 1st to January 31st. The deadline for Semester A proposals is typically mid September. The deadline for Semester B proposals is typically mid March. The Call for Proposals usually open one month before the deadline.
In addition to the biannual semesters of the “Regular” queue, an “Urgent” queue, specifically for science proposals of an urgent nature, remains open for submissions throughout the year.
Call for Proposals for Semester 2026
Below you can find the open call for proposals for semester 2026A and 2026B.
2026B JCMT Regular Call for Proposals
The East Asian Observatory (EAO) is pleased to announce the regular call for proposals for Semester 26B at the James Clerk Maxwell Telescope (JCMT). Please submit your proposals via the JCMT proposal handling system, Hedwig. For full details and submission instructions, please visit:
https://proposals.eaobservatory.org/jcmt/semester/30/regular
The deadline for 26B Principal Investigator (PI) Proposals is April 4, 2026, at 01:00 UTC. The Hedwig system permits the submission (and editing) of proposals until this deadline.
The instruments available for the 26B semester are listed below, along with their respective availability:
- ʻAlaʻihi (86 GHz), ʻŪʻū (230 GHz) and HARP (345 GHz) will be available throughout the semester.
- ʻĀweoweo (345 GHz) is planned to be available during the first half of the semester.
- Kuntur (690 GHz) is planned to be available during the second half of the semester.
ʻAlaʻihi, Kuntur, and ʻĀweoweo are offered in a shared-risk mode. When installed, Kuntur replaces ʻĀweoweo in the Nāmakanui receiver. The precise dates of the instrument swap and the resulting availability will be decided based on instrument demand.
Kuntur is a 690 GHz receiver offered to the JCMT community in collaboration with the Large Latin American Millimeter Array (LLAMA). Kuntur is a sideband-separating (2SB), dual-polarization receiver, with an observable sky frequency range of approximately 609 to 715 GHz (default IF 5.5 GHz).
ʻAlaʻihi is a dual-polarization, single-sideband (SSB) receiver, operating in upper sideband (USB) only, with an LO frequency range of 80.0 to 88.5 GHz. This corresponds to a sky frequency of approximately 86.0 to 94.5 GHz, given an IF of 6 GHz. The instrument’s performance for different IF values (e.g., 7 GHz) is under ongoing characterization.
The respective instrument webpages will be updated with definitive commissioning results for ʻAlaʻihi, Kuntur, and ʻĀweoweo as they become available. For further information, please visit the JCMT instruments webpage:
https://www.eaobservatory.org/jcmt/instrumentation/heterodyne/
PIs must meet the regional or institutional affiliation requirements for Taiwan, Thailand, the United Kingdom, Max Planck Institutes and German universities, or the 26B semester Expanding Partner Program regions (Brazil and Argentina). Co-I status is not similarly restricted. For details regarding PI eligibility, please see:
https://www.eaobservatory.org/jcmt/proposals/eao_eligibility/
If this is your first time using Hedwig, you should use the ‘Log In’ button to generate an account. There is a Hedwig ‘Help’ facility at the upper right corner of each page, and individual Help tags in many other places.
Please contact us at helpdesk@eaobservatory.org if you have any questions.
2026A JCMT Supplemental Rolling Call for Proposals
The East Asian Observatory (EAO) announces a supplemental rolling call for proposals for Semester 26A at the James Clerk Maxwell Telescope (JCMT).
Submissions are also invited for the Semester 26A supplemental rolling call, specifically for proposals with targets in the right ascension (R.A.) range of 09 h to 15 h; observations outside this range will not be scheduled. We particularly encourage proposals with targets visible at elevations above 30 degrees in the middle part of the 09 h to 15 h LST window, as well as those requesting weather bands 3 to 5. A total of 440 hours remains available across all weather bands.
Proposals will be processed on a rolling basis until the Semester 26A queue is full. Submissions must include a technical justification and a science justification, the latter of which is limited to one page (shorter than the requirement for regular JCMT calls). Submitted proposals will undergo immediate internal review by JCMT scientific staff, with evaluations based on technical feasibility and scientific merit.
Please submit your proposals via the JCMT proposal handling system, Hedwig. For full details and submission instructions, please visit:
https://proposals.
The instruments available for the 26A semester are listed below, with their availability dates:
-
ʻŪʻū (230 GHz): Will be available throughout the semester (February 1st – July 31st).
-
HARP (345 GHz): Will be available throughout the semester (February 1st – July 31st).
-
ʻĀweoweo (345 GHz): Is planned to be available from June until the end of the semester (July 31st).
-
Kuntur (690 GHz): Is planned to be available until mid-May.
-
ʻAlaʻihi (86 GHz): Will be available for use throughout the 26A semester.
ʻAlaʻihi, Kuntur, and ʻĀweoweo are offered in a shared-risk mode.
Kuntur is a 690 GHz receiver offered to the JCMT community in collaboration with the Large Latin American Millimeter Array (LLAMA). Kuntur is a sideband-separating (2SB), dual-polarization receiver, with an observable sky frequency range of approximately 609 to 715 GHz (default IF 5.5 GHz). When installed, the instrument replaces the ʻĀweoweo cartridge in the Nāmakanui receiver. ʻĀweoweo is planned to be re-installed in this position in mid-May 2026, in place of Kuntur.
ʻAlaʻihi is a dual-polarization, single-sideband (SSB) receiver, operating in upper sideband (USB) only, with an LO frequency range of 80.0 to 88.5 GHz. This corresponds to a sky frequency of approximately 86.0 to 94.5 GHz, given an IF of 6 GHz. The instrument’s performance for different IF values (e.g., 7 GHz) is under ongoing characterization.
The respective instrument webpages will be updated with definitive commissioning results for ʻAlaʻihi, Kuntur, and ʻĀweoweo as they become available. For further information, please visit the JCMT instruments webpage:
https://www.eaobservatory.org/
For information about PI eligibility and the Expanding Partner Program, please see:
https://www.eaobservatory.org/
If this is your first time using Hedwig, you should use the ‘Log In’ button to generate an account. There is a Hedwig ‘Help’ facility at the upper right corner of each page, and individual Help tags in many other places.
Please contact us at helpdesk@eaobservatory.org if you have any questions.
- Check the JCMT Science Archive to see if data already exists!
- Check if data already exists on your object:
- use the new general clash tool to check if the data already exists on your target (looks through all publicly available data).
- Are you eligible to submit as PI ? – check your nationality / affiliation here
- JCMT Proposal Collaboration rules are described here
- Proposal Submission
- Preparing justification files
- Submissions Checklist
- Closed calls for proposals
or – – if you are ready to go: login to Hedwig. Good Luck!