Call for PSU HET Proposals: 2026-2 Trimester

Announced by email on 6/15/2026

The PSU HET TAC invites proposals for PSU HET time for the 2026-3 trimester, running from 2026 August 1 through 2026 November 30. Phase I proposals for this trimester are due by 5 pm (U.S. eastern time) on 2026 June 30. Proposals submitted after the deadline but before the submission form is disabled will be summarily rejected and not reviewed by the TAC (one may still be able to submit after the deadline and one may get an email acknowledgement but such late proposals will not be forwarded to the TAC for review and the principal investigator will not receive any post-review notice). Please read the instructions below carefully and pay particular attention to the proposal submission roadmap. 

During the 2026-3 trimester, the PSU TAC will be able to allocate 7, 20, 28, and 28 hours in priorities 0, 1, 2, and 3, respectively. Priority 4 time will be awarded for targets that can use poor seeing and/or non-spectroscopic sky conditions. Priority 4 targets will be charged only half of their exposure time and no setup time. There is no opportunity for long-term proposals at this time.

Please note the following for this proposal cycle:

• Status of HPF: The Habitable Zone Planet Finder (HPF) will need to be warmed up in the HET 26-3 trimester to ensure its charcoal getters are refreshed, since its vacuum is degrading. This is part of standard maintenance that is required once every 3-5 years to refresh the getters. Normal HPF observations are planned for August 2026. HPF will be entirely unavailable for at least one month in the September-November timeframe and may be unavailable for up to two months. Observations for science programs that do not need high precision radial velocity or high instrument stability will resume before higher precision science observations. As a result proposers are highly encouraged, in the 26-3 trimester, to put in programs requiring both lower precision HPF observations as well as LRS-2 and VIRUS programs that can be executed in bright time to ensure that the HET has flexibility to maximize science observations.

• Updated Instructions and Reminders for Target-of-Opportunity Proposals: As of the 2026-1 cycle, proposals requesting ToO time must include in the "Experimental Design" section of the proposal an estimate of the probability that the requested time will be used and explain the rationale behind that estimate. Moreover, ToO programs requesting P0 time must consider carefully and specify the required observing conditions to achieve the desired rapid response. Careful consideration is needed because the requirement of rapid response may compete with requirements/constraints on observing conditions (e.g., background level, seeing, transparency). The resident astronomers will need clear guidance on these matters; the default interpretation of the constraints is to carry out the requested observations as soon as the observing conditions meet the requirements expressed in the proposal.
  The following sections (tabs) of this web site have been updated to reflect the new instructions:
   Primer : See new section entitled "Target-of-Oportunity (ToO) Observations"
   Forms : See updates to the sections entitled "Experimental Design" and "Description of Observations"

• The proposal forms were updated in the summer of 2024. The current version of the proposal template and class file is v.24-5 (see the Forms tab). Everyone must use the current version. The instructions on filling out the proposal forms have been updated accordingly. The current version, introduced in the 2024-3 trimester, includes major revisions in the section entitled "Plan for Reduced Allocation," previously entitled "Contingency Plan." The new title and revised instructions for this section are intended to remove any ambiguity in what this section should include. All proposers are strongly encouraged to read all the instructions for all sections carefully and pay particular attention to the instructions on the section entitled "Plan for Reduced Allocation." 

• The HETDEX conflict calculator, incorporated in the Object Observability and Feasibility Calculator, was updated to take into account the end of the HETDEX survey in the summer of 2024, which means that all proposed programs after the end of HETDEX will not be affected by HETDEX conflicts. Proposers who use the observability and feasibility calculator can turn off the HETDEX conflict checks.

• The TAC has noticed a number of issues in recent proposal cycles that are related to (a) not understanding and/or not following the proposal instructions and (b) bad formatting of the proposals themselves. 

As a matter of basic equity, everyone has to follow the same instructions and be held to the same standards. The TAC has asked the TAC chair to inspect proposals after submission and remove extra pages that violate the page quota (e.g., extra pages with figures and/or references beyond the standard quota). Moreover, the TAC may summarily reject proposals that do not follow the instrucitons or the proper formatting. Here are some specific cautions:

Use the current proposal form, not any of the old versions. 

Do not change the fonts or the margins (or any other formatting specification) of the proposal template. For example, the references and figure captions should have the same font as the main text.

Make sure that the figures and all their labels are clear and legible. It often happens that a figure is shrunk to fit into the space available with the result that the fonts shrink accordingly and the labels become illegible. Be careful to avoid this problem.

Do not go over the space allotted for particular sections of the proposal, not even by a single line.

Instruments and Priorities

The following instruments are available on the HET at this time: 

• LRS-2 (Low Resolution Spectrograph, Blue and Red cameras). 

• HPF (the Habitable Zone Planet Finder) is an extremely stable high resolution near-infrared echelle spectrograph. Proposers interested in doing precise radial velocity work with HPF should include a credible plan for deriving velocities from HPF data products and include HPF team members as co-Is. 

• VIRUS (Visible Integral-Field Replicable Unit Spectrographs) is a mature instrument but observations are still considered to be on a shared-risk basis because the instrument is complicated and (78 IFUs and 156 CCDs; not all of them will work perfectly all the time). 

Please check the main HET web page (and links therein) for an overview and latest Phase II and published instrument information. 

Note that Penn State’s P3 observations have a lower chance of being completed (~40%, based on historical weather patterns). 

Roadmap for Preparing and Submitting a Proposal

The materials needed to put together and submit a PSU HET proposal are described in the Forms tab of this web site. Included are a number of documents with information and instructions (described briefly and linked directly below) as well as the LaTeX form needed for the science proposal. 

Here are the main stages of the proposal preparation and submission process:

• If you are not an experienced HET user, please start with the Primer tab. We also recommend that you consult the Hints & Tips tab for some useful advice.

• Put together the science proposal and the target list as described in the Forms tab. At the end of this stage you should have produced a single, self-contained PDF file. 

Follow the instructions on the Submission tab to submit your proposal (that is, the PDF file produced in the previous stage). The submission is carried out through this Google form. Upon successful submission, you will receive an email confirmation. The proposal must be submitted by the deadline given above. Proposals received after the deadline and before the submission form is disabled will be summarily rejected and not reviewed by the TAC (you may still be able to submit for a short period of time after the deadline and get an email acknowledgement but that does not mean that such proposals will be reviewed). Similarly, proposals that do not follow the instructions (e.g., the format is not right or files do not follow the proper naming conventions) may also be summarily rejected.