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 2026A
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).
This call invites proposals for targets with right ascension (R.A.) between 06 h and 15 h; observations outside this range will not be scheduled. A total of 500 hours is available for this call, distributed 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:
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ʻŪʻū (230 GHz): Will be available throughout the semester (February 1st – July 31st).
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HARP (345 GHz): Will be available throughout the semester (February 1st – July 31st).
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ʻĀweoweo (345 GHz): Is planned to be available from June until the end of the semester (July 31st).
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Kuntur (690 GHz): Is planned to be available until mid-May.
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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!