NASA IRTF Fall 2026 Newsletter

Last updated 30 August 2026

Proposal Deadline for Semester 2027A (February 1, 2027 to July 31, 2027) is Thursday, October 1, 2026, 5PM Hawaii Standard time.

Available instruments are listed here. Remote observing is offered for all projects, training on IRTF facility instruments and support for in-person obsrtving is available for new observers. Each observing program has an assigned support astronomer. Click here for more information on remote observing.

Staff Update

Neal Matsude started as electronic technician on the day crew in May 2025. Neal joins us from Gemini North. Raycen Wong was also recently recruited as a Mechanical Engineer for IfA. IRTF shares Raycen’s time with the other IfA facilities at a level of about 30%. For IRTF Raycen is currently working on weather proofing the telescope dome and improving light baffling in MIRSI. Raycen joined IfA from CFHT. Importantly, these recruitments bring the day crew back up to full complement.

Telescope Maintenance

We are planning two significant telescope maintenance projects. The first is to remove remaining areas of asbestos from the telescope building. The second project is to remove flaking paint and repaint the exterior building walls, and to repair damaged areas for the roof (the result of decades of ice falling from the dome and onto the flat roof) that are an increasing source of water leaks. We anticipate that work will be scheduled sometime during 2027 and will require one or two weeks of telescope downtime.

Telescope Pointing

We conduct telescope pointing runs at least once per semester. Following an updated pointing map we typically find pointing good to one-sigma = 20" for average slews of 10-20 degrees. Consequently, it is not infrequent that a target can lay just beyond the 60" FOV of the Guidedog, for example. The best way to guarantee pointing is to get the TO to go to a nearby star (typically with one degree) and offset from there. Pointing is usually then good to within a few arcsec.

Over the decades as we've added several large facility instruments to the telescope, pointing has not too surprisingly suffered. The pointing map uses the TPOINT algorithm developed by Pat Wallace in the 1980s and which has subsequently been used in modified form by many large telescopes, including IRTF. We've recently engaged Pat to investigate modifying TPOINT to add additional parameters to account for the extra flexure we're probably experiencing due to larger distributed instrument mass on the back of the telescope. We should see within the next few months if we’re able to improve telescope pointing.

Strategic Planning

The preparation of the "10-year strategic plan for the NASA IRTF" is proceeding well. The process was started in September 2025. The framework of the plan has been developed, various sections have been drafted, but much work remains.

The phase of collecting community inputs to guide the scientific priorities, future operations plans and instrument development, and to ensure that IRTF has a positive impact for the local community is continuing. Almost 200 respondents provided input to the online community survey. The winner of the IRTF observing time for survey respondents is Trudi Hoogenboom, a Planetary Scientist and Educator who will use the time for an observing program that exposes students to astronomical science.

About 130 people volunteered to be part of the IRTF Affinity Group and requests for science cases and instrument ideas will be sent to them.

In June, we held an IRTF townhall at the summer AAS meeting where we ran an activity to collect ideas for 'Changes to Operations', 'Science Cases', 'User Supports and Archive', and 'Instrument Ideas'. IRTF will have a booth at the AAS Division of Planetary Science Meeting in Spokane, Washington (25-30 October).

Ensuring that IRTF supports the goals of the NASA's PDCO and NASA's broader goals, and is well integrated into the NASA ecosystem of facilities and research programs, has a strong community guided roadmap for enhancing capabilities and operations will mean that the IRTF continues to support cutting edge and globally important science programs.

If you have any questions, any inputs and opinions, or are interested in participating in the strategic planning process, please let Warren Skidmore (warren.skidmore@hawaii.edu) know.

Target of Opportunity (ToO) Programs and Director Discretionary Time (DDT)

Proposals for Target of Opportunity (ToO) programs are fully supported and are encouraged for programs when times of an event cannot be predicted. ToO interrupt proposals should include at least one team member capable of carrying out the observation without support from the IRTF staff.

The total time that can be allocated to all ToO programs in a semester is 24 hours for Solar System and 24 hours for non-Solar System proposals. Each ToO interrupt is limited to 3 hours in length. The proposal must also clearly define the criteria by which a ToO interrupt would be initiated. Time for ToO interrupts will be taken from scheduled, non-time critical observing programs. Programs affected by ToO interrupts will be offered make-up time from Director Discretionary Time (engineering time) when possible.

The IRTF schedule includes about 18 nights per semester for engineering. This time is used to address technical problems with the facility, calibrate instrumentation, IRTF staff science, and for Director’s Discretionary Time.

A ToO trigger, or a request for Director's Discretionary Time (DDT) should be submitted by email to John Rayner (jrayner@hawaii.edu), Warren Skidmore (warren.skidmore@hawaii.edu) and Adwin Boogert (aboogert@hawaii.edu), and must include target information and preferred observing times and dates. In addition, a DDT request should also include a strong programmatic or scientific justification, a technical description of the proposed observations (instrument settings, required S/N, and justification for the amount of time requested), and a discussion for why this work was not proposed in the last proposal cycle and why it can’t wait for the next proposal cycle.

The fraction of engineering time offered to observers for DDT events that could not be foreseen and supported through a ToO program is reserved for follow-up of newly-discovered objects and of unexpected transient phenomena, or when developments since the last proposal cycle make time-critical observations necessary.

Evaluation of DDT requests will be based on the same criteria used for regular observing proposals, and on the urgency or time-critical nature of the observation. Observers should not submit DDT requests if the request could have been proposed as a ToO proposal with specific interrupt criteria (e.g., comets, novae, NEO flybys etc.). As with ToO interrupt proposals, DDT requests should include at least one team member capable of carrying out the observation without support from the IRTF staff. In addition, observers may request DDT outside of the scheduled engineering time for events requiring fast response.

DDT observations have no proprietary period and are made publicly available via the IRSA archive very soon after the observations are obtained.

Observers should not negotiate with scheduled observers. All program changes, including those by the PI and/or observer for already scheduled time must be approved by the Director.

Applying for Observing Time

The IRTF implements Dual-Anonymous Peer Review (DAPR) procedures in the review and ranking of observing proposals, as is now common practice for all major astronomical facilities. Applications are required to submit proposals that meet NASA DAPR requirements criteria for anonymity. The goal of DAPR is to remove cognitive bias during the review process, not make identification of the applicants impossible. Violations of the DAPR requirements may mean a proposal is penalized or even rejected. PLEASE follow the DAPR Proposal Instructions when preparing your observing proposal.

Should you have any questions about the DAPR rules please contact Warren Skidmore (warren.skidmore@hawaii.edu).

Telescope time is divided 50/50 between Solar System and non-Solar System allocations, not including the 18 nights for engineering. There is a solar system TAC and a non-solar system TAC, each with four or more members. The TAC is independent of the IRTF although IRTF staff give input to the TAC on the feasibility of the submitted technical case. The TAC panels read and discuss proposals and then score them on a metric that weights the science and technical case, and subtracts points depending on any DAPR violations.Beginning in semester 2026A, we instigated an Additional Credit system for the support of NASA’s strategic goals. This includes NASA science, mission support, and planetary defense.

We occasionally receive proposals with poor technical cases, usually from groups that are not familiar with the telescope and suite of observing instruments. If in doubt, IRTF staff (irtf-support@lists.hawaii.edu) can be contacted for help with the technical case provided you contact them well in advance of the proposal deadline. Since not all of the TAC are likely to be familiar with your particular area of science, please make sure to describe the big picture motivation for your science program.

FELIX: new off-axis guider and low-order wavefront sensor

FELIX is the off-axis telescope CCD-guider and low-order (2x2) Shack-Hartman wavefront sensor (WFS) for IRTF. In guiding and focus control modes, it patrols a U-shaped 50 square arcminute field in the telescope image plane surrounding the 80 arcsec diameter on-axis FOV available to Cassegrain-mounted instruments. The guider images an 80 arcsec diameter FOV and can support non-sidereal tracking using moving guide boxes). Under the control of the telescope operator, standard operating mode for FELIX during most science operations is to measure the wavefront and provide inputs for automatic real-time closed loop focus control using stars as faint as V=18 in about one minute. Because of the improved focus control, we see measurable sensitivity improvements for the slit spectrographs. Felix has been in service since March 2025. The utilization of the WFS output to control the IRTF Adaptive Secondary Mirror is being developed (see below). For more details contact Mike Connelley (mconnell@hawaii.edu). FELIX is routinely used with all Cassegrain-mounted facility and visitor instruments.

Adaptive Secondary Mirror (ASM) Project

In Oct 2025, the ASM was successfully tested with FELIX for the correction of static aberrations (active optics) and seeing enhancement. Using SpeX’s SXD mode and the 0.3" slit, we have measured an improvement in throughput by a factor of 1.6 in enhanced seeing mode. The measurement does not include gains from active optics, which is expected to be a similar amount. The ASM is also capable of a 5" chop at 4 Hz with closed-loop correction from FELIX at both ends of the chop.

Although we do not offer enhanced seeing for general use at this time, ‘Facilitizing’ the ASM is the thesis project of Ellen Lee (ellenlee@hawaii.edu). Routine use of the ASM for active corrections with off-axis wavefront measurements from Felix is tentatively planned for early 2028, contingent upon further testing and availability of IRTF staff for technical support. For more information contact John Rayner (jrayner@hawaii.edu).

Facility Instrumentation Update

The end-to-end telescope and instrument throughput is being regularly monitored. After recoating the secondary mirror and with regular cleaning of the instrument entrance windows overall throughput is being monitored and maintained. Electronic observing logs are automatically generated for all facility instruments. Details of data reduction packages and tools for all spectrographic and several imaging instruments are on the IRTF data reduction page. Available facility instruments include:

(1) SpeX is a 0.7-5.3 micron medium-resolution (R=50-2500) spectrograph and imager/guider. The 0.8 micron cut-on dichroic was replaced with selectable 0.7 and 0.9 micron dichroics that send light to MORIS for optical guiding and imaging. When observing, we strongly recommend that at least three nodded pairs of integrations are acquired, even if the source is bright. This allows for more accurate measurement of the spectral slope in the presence of seeing and guiding variations. Longer integration times also help even out seeing variations, even if they are not required to achieve the desired S/N. Real-time spectral extraction runs automatically in the background and can be visualized in the data viewer (DV). For more information, see the IRTF Instrument Page and instrument manual or contact Mike Connelley (mconnell@hawaii.edu).

(2) MORIS is a 512x512 pixel Andor CCD camera mounted at the side-facing, dichroic-fed window of the SpeX cryostat (60"x60" field-of-view). MORIS can be used as an optical imager and as an optical guider for SpeX. For IR science targets with significant optical flux, guiding with MORIS can significantly improve spectral sensitivity (better than one magnitude compared to IR guiding due to reduced slit losses). For more information, see the IRTF Instrument Page and instrument manual or contact Mike Connelley (mconnell@hawaii.edu).

(3) iSHELL is a 1.06 – 5.3 micron cross-dispersed echelle spectrograph (up to about R=80,000) and imager. Slight fringing (5% contrast, spatial frequencies of 20 pixels at J to 70 pixels at M) is observed in the flat fields. To reach S/N>100 on features at these pixel frequencies, frequent flat fielding is required (for details contact your support astronomer). The general purpose data reduction tool for iSHELL is available as part of the Spextool package. We have developed a version of Xtellcor (called Xtellcor_model) that uses atmospheric models instead of standard stars to remove telluric absorption lines in iSHELL spectra. We recommend that observers take standard stars until they have compared both methods. Observers are reminded that darks are automatically taken following observing and can be downloaded. Real-time quicklook spectral extraction now runs automatically in the background and can be visualized in the data viewer (DV).

On a timescale of a year, the radial velocity stability is limited by systematics. Commissioning observations involving radial velocities demonstrated precisions around 10 m/s achieved for targets brighter than K=10. 3-5 m/s has been achieved for bright, K~4 mag stars (Cale, Plavchan, et al., 2019, AJ 158, p. 170), however the number of iSHELL radial velocity epochs that can be scheduled is typically at most ~25 per semester, and less for low declination targets. The RV data reduction code is available on github or by request from Peter Plavchan (pplavcha@gmu.edu).

For more information, see the instrument page and instrument manual or contact Adwin Boogert (aboogert@hawaii.edu).

(4) ‘Opihi is a wide-angle finder mounted to and aligned with IRTF. ‘Opihi consists of a 17" Planewave CDK telescope, a CCD having a 32’ FOV, and a filter wheel with g'r'i'z' and open filters. Its goals are to recover asteroids with large position uncertainties for SpeX and MORIS, to flux calibrate SpeX prism or SXD spectra by simultaneously imaging in z'-band, and to monitor extinction and cloud cover (similar to CFHT’s Skyprobe). ‘Opihi can locate asteroids down to V~20 in about one minute, propagate its motion across the sky, and send that ephemeris to the Telescope Control System. ‘Opihi is independent of other facility instruments and can thus be used in parallel with SpeX. Opihi has been used to gather multicolor photometry of various science targets. For more details contact Mike Connelley (mconnell@hawaii.edu).

(5) MIRSI/MOC is a 5-20 micron camera and grism spectrograph, and optical imager. MIRSI was upgraded with a closed-cycle cooler to replace its liquid nitrogen and liquid helium cryostat, and a dichroic-fed optical channel added (MOC, similar to MORIS). First light with the upgraded instrument occurred in April 2020. During semester 2023B, the engineering grade array was replaced with a science grade array. Current MIRSI capabilities are given here. Unfortunately the sensitivity has not been improved despite work to optimize the read out. We are currently working with a pre-thesis student to acquire fast imaging data as a proxy to estimate improvement of sensitivity through chopping. As part of this process we’ve found what is possibly a large internal light leak. This could also explain the loss of sensitivity and why optimization of the array clocking has not resulted in any improvement (signal dominated by the leak). Consequently, MIRSI will not be offered during semester 2026B as we attempt to find and fix the leak, and then optimize the read out. For more information contact John Rayner (jrayner@hawaii.edu).

(6) TEXES is a visitor instrument. Observing time with TEXES, 5-20 micron high-resolution spectrograph, will be offered in 2027A. TEXES is a PI-led visitor instrument and is made available on a collaborative basis with the instrument team: please contact Tommy Greathouse (tgreathouse@swri.edu) for more information.

Information on available instruments and performance can be found on the IRTF Instrument Page. Exposure time calculators for SpeX and iSHELL are available on the respective instrument webpages. The ETC for iSHELL has been adjusted to allow for the lower throughput at J0.

New IRTF Facility Instrumentation Under Development

SPECTRE (Spectrograph Express - Planned first light late 2028) is a 0.4-4.2 micron, R=250, integral field spectrograph (IFS). For optimum efficiency, the wavelength range is covered simultaneously in three channels - 0.4-0.9 micron, 0.9-2.4 micron, and 2.4-4.2 micron, and the IFS has a 7.2x7.2 arcsec FOV to remove slit losses and to acquire absolute photometry on point sources. Object acquisition and guiding is done with an external cryostat-mounted 3 arcmin FOV CCD. On-target guiding can also be done at 1 Hz by taking advantage of H2RG non-destructive reads and collapsing the 3D data cubes. Apart from a pupil viewer there are no cold mechanisms, facilitating easy and once-per-night calibration. High priority science cases include: the characterization of NEOs and small bodies, in particular, followup of targets identified with NASA's NEO Surveyor, and optical-IR transient follow-up and variability. The cryostat vacuum jacket, cold optical bench and numerous other parts have been delivered, and integration is underway at IfA-Hilo prior to cold testing in early fall 2026. This testing will include everything except for the long-lead optics (IFU and dispersing prisms). Most hardware with the exception of the cold optics is now in hand. Assembly, integration and testing (AIT) is taking place at IfA-Hilo. The H2RG arrays used in the NIR and MIR channels are already in-hand, and MIT-LL is providing a science grade spare optical CCD from the NASA TESS mission. We anticipate first light by late 2028. A SPECTRE observations simulator and data reduction package (DRP) are being written in Python. The simulator will be the basis for an online observing time estimator. This project is part of the IfA student Kenji Emerson’s PhD thesis work. We are also investigating the feasibility of an automatic spectral classifier as an add on to the DRP.

Please see SPECTRE 2026B update for more details. SPECTRE is funded by NASA. For more information contact John Rayner (jrayner@hawaii.edu).

Help Keep Our Publications List Current

Please continue to acknowledge the IRTF in your publications following the instructions shown here. This is a formal requirement for any publications using IRTF observations and failure to do so will be considered during the TAC process. It is important that you include in your papers the name of the instrument used and the citation for the instrument, as this helps to ensure future funding of IRTF instruments.

To keep our online bibliography up to date, we ask that you send us citations to your latest IRTF publications. You can verify that your refereed publications are listed in our bibliography at:

https://ui.adsabs.harvard.edu/search/q=bibgroup%3A%22irtf%22&sort=date%20desc%2C%20bibcode%20desc&p_=0

Please send any missing references to Warren Skidmore (warren.skidmore@hawaii.edu).

We are in the process of compiling a list of PhD Dissertations that have utilized observations obtained with the IRTF.

https://irtfweb.ifa.hawaii.edu/research/biblio/dissertations.html

If you (or your student) has written a dissertation based on IRTF data that is not yet included in this list, please send the appropriate information (including a web link to the dissertation, if possible) to Warren Skidmore (warren.skidmore@hawaii.edu).

IRTF Spectral Libraries

Users are encouraged to make use of the spectral library of FGKM stars, which is available here. An extended spectral library including late-type non-solar stars observed by Alexa Villaume and collaborators is available here. Contact John Rayner (jrayner@hawaii.edu) for more details.

A library of more than 1000 prism spectra of low-mass stars and brown dwarfs is maintained by Adam Burgasser, and is available here.

The MIT-IRTF Near-Earth Object spectral survey is underway, and many spectra are publicly available. For more information go to http://smass.mit.edu/minus.html.

IRTF Data Reduction Update

Spextool for the SpeX instrument is being converted from IDL to Python by Mike Cushing (University of Toledo) and Adam Burgasser (UC San Diego). This eliminates the need for an IDL license, and enables data reduction with scripts, on the Python command line, and with Jupyter notebooks. A beta version of pySpextool for the Prism, SXD, and LXD modes is available on GitHub. It does not have GUIs yet, and while currently some Jupyter notebooks are available, there is no full manual yet. Users are invited to submit issues on GitHub and feedback is welcome.

All IRTF observers have the option to reduce their SpeX and iSHELL data remotely, on a dedicated IRTF computer instead of installing the software on their own machine. This computer, which is accessed via VNC, has IDL and the latest versions of Spextool for SpeX and iSHELL installed. Observers can request a temporary guest account by emailing their support astronomers. For more information, see here.

A beta version of Xtellcor_model is available, which uses atmospheric models instead of standard stars to remove telluric absorption lines in iSHELL spectra. The software, sample data, and a manual can be downloaded from the IRTF data reduction pages. Alternatively, the program can be run remotely on an IRTF computer in a VNC session. Optimization of the atmospheric column densities to the observed spectra is typically required, and thus the method works best if at least a few telluric lines are separated from stellar features. The telluric model can be further optimized interactively. Xtellcor_model also corrects for the iSHELL echelle order curvature using template spectra. We still recommend that observers plan to take standard star spectra until they have verified that Xtellcor_model satisfies the calibration needs for their science programs.

Fully automated "quicklook" reduction of SpeX and iSHELL spectra is operational during every observing session. This enables observers to assess the quality of their data in (near-) real-time and make better informed decisions. During an observing session, the software determines from the FITS headers if sufficient data is available to run a scripted version of Spextool. It then automatically extracts spectra and displays the signal and signal-to-noise values as a function of wavelength in DV (before division over a standard star). For more information, visit the Quicklook web page.

Please visit the IRTF data reduction pages for downloading the Spextool software for both SpeX and iSHELL, as well as sample data and other useful resources, and do not hesitate to contact Adwin Boogert (aboogert@hawaii.edu) for requests and questions about the reduction of IRTF data.

Data reduction resources for MIRSI that have been developed by regular users and made available by them to the community can be accessed via the IRTF data reduction pages.

Data Archive

The IRTF Data Archive is hosted by the NASA/IPAC Infrared Science Archive (IRSA) at: https://irsa.ipac.caltech.edu/Missions/irtf.html. For a tutorial on using the archive, see here. Raw data files taken with SpeX beginning Aug. 1, 2016, and with iSHELL beginning Feb. 1, 2017, are now publicly available via this site after a proprietary period of 12 months. As part of the archive process, the abstract field on the observing proposal form is being preserved and provided as metadata when data files are searched for or downloaded from the archive. For iSHELL and SpeX spectroscopy observations performed in the standard observing modes in semester 2019B and onward, best-effort automatically generated figures are available showing the extracted spectra and signal-to-noise values.

In June 2019, the IRTF Legacy Archive website was opened to the public. This site provides search and download capabilities for raw IRTF data files taken between 2001 and mid-2016. Possible search parameters include semester, start and end dates of the observations, program ID, target name and coordinates, and observer. Download of the data files is performed using a retrieval script that is generated from the search results. The Legacy Data are provided "as is" with no guarantee of quality or associated metadata other than the information contained in the fits file headers.

Adam Burgasser (UC San Diego) is leading a team that is using pyspextool to batch process archival SpeX data from the 2000-2020 period. Reduced data for those periods that have been processed will be provided to the community via the IRTF IRSA Archive; raw data for observations up to 2016 are currently served in the IRTF Legacy Archive and in the NASA/IPAC Infrared Science Archive for 2017 and later. As of August 2025, processing of the 2009-2010 SpeX observations is about 50% complete, and is expected to be part of a preliminary release later this year. Batch processing is typically carried out as part of undergraduate research projects where all observations of a particular type of object are systematically reduced and studied. The resulting catalogs of spectral data for asteroids, stars, galaxies, and other astronomical objects will be available for the community to use in any study, with the acknowledgement message posted on the IRTF website.