NASA IRTF Fall 2025 Newsletter
Last updated 1 September 2025
Proposal Deadline for Semester 2026A (February 1, 2026 to July 31, 2026) is Wednesday, October 1, 2025, 5PM Hawaii Standard time.
Available instruments are listed here. Remote observing is offered for all projects, limited logistical supports for in-person observing and training on IRTF facility instruments is available for new observers. Each observing program has an assigned support astronomer. Click here for more information on remote observing.
New IRTF Contract
Following an RFP on 11 March, 2024 and our proposal submittal in June 2024, NASA awarded UH a new operating contract to run IRTF on July 1, 2024. The contract is valued at 85ドルm (including 10ドルM in contingency) and covers the period from July 1, 2024 to January 1, 2033 (the end of the current Maunakea lease). Of course, this is not an absolute guarantee of funding since continued funding is contingent upon federal funding at NASA but it is an indication of strong support of IRTF following the very positive independent review of IRTF science and operations in early 2023:
https://science.nasa.gov/wp-content/uploads/2023/07/irtf-report.pdf
A part of the new NASA contract award (2024-2033) to UH for IRTF operations was a requirement to include a Diversity, Equity, Inclusion, and Accessibility (DEIA) Plan, which we duly did. On January 23, 2025 we received an official contract amendment from NASA instructing us to remove all DEIA efforts. The DEIA plan included community outreach activities. It is currently unclear how the amendment affects outreach efforts. NASA HQ has informed us that outreach efforts are still allowed.
Staff Update
We are very happy to report that Warren Skidmore (warren.skidmore@hawaii.edu) joined IRTF as Deputy Director on July 14, 2025. Warren comes to us from TMT where he was Instrumentation System Scientist, leading the development of the TMT Detailed Science Case and other science, operations and instrument related efforts. At IRTF in addition to management duties, Warren will organize the development of the new strategic plan with important input from the community, eventually take over telescope scheduling, and help with observer support at the telescope.
The IRTF Senior Engineer, Charles Lockhart, resigned in early January, 2025, to take an exciting position at a commercial satellite company in California. Fortunately, Charles will continue with IRTF part-time to continue work on the SPECTRE array controller development, and the MIRSI array read out. We also recently recruited Richard Sevao as Junior Software Engineer primarily to work on the Telescope Control System but also on control of the visible guiders. Franccesca Scheckel was hired as Telescope Operator Assistant on April 28, 2025.
The IfA recently recruited Raycen Wong as Mechanical Engineer for UH telescopes. Raycen comes from CFHT. About 25% of Raycen’s time is to work with the IRTF day crew on telescope needs. We are also recruiting a Mechanical Technician for the day crew. As a result of an extensive safety audit of the telescope in 2023 the day crew have been working diligently to fix all the identified problems. Many new safety programs and reporting requirements are now in place. The NASA HQ Safety Officer is very happy with progress.
Strategic Planning
A major recommendation from the NASA Independent Review and the NASA IRTF/Keck User Group is for IRTF to develop a strong strategic plan in order to ensure "its supremacy as a planetary facility" and its ability to serve the astronomical and solar system science community for the next decades.
Over the next 18 months, we will develop a strategic plan that includes both near and long term plans for instrumentation development, improvements in operations, and enhancements to the IRTF data archive. To develop the plan, we will consider future funding, synergies with existing and future ground and spaced based observing facilities, the shape and evolution of the scientific landscape, in particular relating to solar system science and planetary defence but also including astrophysics more broadly, NASA and US federal benefits from IRTF, etc.
The development of the strategic plan will require significant community input, details of how that will be gathered are still being developed. However, we will need a core working group and multiple topical sub-groups. We will run community events at major meetings and send surveys out to collect inputs.
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.
Engineering Time and Director Discretionary Time (DDT)
The IRTF schedule includes about 18 nights per semester for engineering. This time is used to address technical problems with the facility, calibrate instrumentation, and for IRTF staff science. Some of this time can be offered to observers in the form of Director’s Discretionary Time (DDT). DDT 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. A request for DDT should be submitted by email to both John Rayner (jrayner@hawaii.edu) and Adwin Boogert (aboogert@hawaii.edu), and must include a strong programmatic or scientific justification, a technical description of the proposed observations (including target information, 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.
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 avoid 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.
Observers should not negotiate with scheduled observers. All program changes must be approved by the Director.
Applying for Observing Time
The IRTF was instructed by NASA Headquarters to implement Dual-Anonymous Peer Review (DAPR) procedures in the review and ranking of observing proposals, as is now common practice for all major astronomical facilities. The updated process was implemented beginning with the 2022A semester. To facilitate the new process some changes were made to the Online Application Form, and instructions for preparing the proposal attachment file were updated to meet the NASA DAPR guidelines. PLEASE follow the directions for preparing your proposal for observing time CAREFULLY. Any proposal that does not make a good-faith effort to maintain anonymity WILL BE REJECTED.
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. Starting this semester, we are adding a weighted scoring metric 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.
Should you have any questions about the DAPR rules please contact Adwin Boogert (aboogert@hawaii.edu).
FELIX: new off-axis guider and low-order wavefront sensor
FELIX is the new off-axis telescope guider for IRTF. It consists of a CCD, optics and pick-off mirror on an XY stage. The pick-off mirror 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. In addition to imaging an 80 arcsec diameter FOV, the optics can switch to a 2x2 Shack-Hartman wavefront sensor (WFS). By measuring the wavefront and controlling the hexapod secondary the system will initially provide real-time focus and alignment correction. Since only slow correction is needed, closed loop correction can be done on stars to V=18 in about one minute. Aside from atmospheric seeing, defocus is currently the largest error in the telescope's image quality budget. FELIX is available for use with all Cassegrain-mounted facility and visitor instruments. Through the resulting better focus control, we expect sensitivity improvements of up to 0.5 mags for the slit spectrographs. Felix has been in service since March. For more details contact Mike Connelley (mconnell@hawaii.edu).
Adaptive Secondary Mirror (ASM) Project
The ASM team completed two successful runs in May and July 2025. The ASM is currently capable of closing the loop with FELIX to correct for static aberrations. Due to an error with the slope calculations, static aberration measurements with FELIX were not as sensitive as expected, which limited the quality of active optics correction. This has been fixed and will be tested during the next on-sky run. We have also been investigating the possibility of chopping the ASM to improve the sky background measurement in MIRSI. The ASM is capable of providing diffraction-limited image quality for a 2" chop at 5 Hz. A higher amplitude (~5") and faster rates are likely possible, but we were unable to test this during the previous run due to the limited subaperture size of Mark Chun's test 12x12 WFS and very poor seeing conditions. A week of engineering is scheduled in late September 2025 to continue integrating the ASM with FELIX. We hope to test new software designed to run the ASM purely off of FELIX data, which requires operating WFS mode at much higher speeds than the current instrument control software is able to. This will allow the ASM to improve the sensitivity of IRTF's instruments through chopping and seeing improvement when possible.
‘Facilitizing’ the ASM is the thesis project of Ellen Lee (ellenlee@hawaii.edu). For more information contact John Rayner (jrayner@hawaii.edu).
Facility Instrumentation Update
We’re currently addressing the problem of reduced telescope throughput. This is attributed to the degradation of the coating on the secondary mirror. We plan to have the mirror recoated in time for semester 2026A and so current instruments ETCs can be used as is for preparing observing proposals. While recoating takes place, a spare secondary mirror with a good condition reflective surface has been installed and throughput has increased significantly across optical and infrared wavelengths. Available facility instruments include:
(1) SpeX is a 0.7-5.3 micron medium-resolution (R=50-2500) spectrograph and imager. The 0.8 micron cut-on dichroic was replaced with a 0.7 micron dichroic during semester 2017A. This modification increases the spectral wavelength grasp for optically guided solar system targets. Sub-arrays and movie mode are working again in the IR guider. When observing point sources, 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 variations, even if they are not required to achieve the desired S/N. Electronic observing logs are automatically generated. Real-time quicklook spectral extraction runs automatically in the background and can be visualized in the data viewer (DV). For more information, see the 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 visible targets guiding with MORIS can significantly improve spectral sensitivity (better than one magnitude compared to IR guiding due to reduced slit losses). Electronic observing logs are automatically generated. For more information, see the 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 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, more frequent flat fielding is required (for details contact your support astronomer). Commissioning observations involving radial velocities demonstrated precisions better than 10 m/s achieved for targets brighter than K=10. The RV data reduction code is available on github or by request from Peter Plavchan (pplavcha@gmu.edu). 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. For now we recommend that observers still take standard stars until they have compared both methods. For details see the IRTF data reduction pages. Electronic observing logs are automatically generated. 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). For more information, see the instrument page and instrument manual or contact Adwin Boogert (aboogert@hawaii.edu).
(4) 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 the use of a science grade array. We suspect that the array clocking needs to be further optimized. In an effort to better characterize performance a pre-thesis student project will be undertaken over the next year to measure optimum chop frequency using on-sky data, and to measure instrument throughput. Due to the lack of sensitivity, we are not offering spectroscopy in 2026A (see the Call for Proposals). In the longer term we are hoping to further improve performance by replacing degraded filters and by adding a chopping capability to the hexapod secondary stage. For more information contact John Rayner (jrayner@hawaii.edu).
(5) ‘Opihi is a wide-angle telescope mounted to and aligned with IRTF, consisting 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).
Information on available instruments and performance can be found here. The instrument manuals were updated in August 2021. 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=150, 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. Fabrication of the cryostat vacuum jacket and cold optical bench is underway and most of the major hardware (including the two H2RGs) and various optics are in hand. Please see Spectre 2026A 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.
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.
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.
For the Spectre 0.4-4.2 μm IFU spectrometer, which is in development, an observations simulator and data reduction package 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.
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 Archive
The IRTF Data Archive is hosted by the NASA/IPAC Infrared Science Archive (IRSA) at: https://irsa.ipac.caltech.edu/Missions/irtf.html. 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 18 months from the date of observation if taken in the 2024B semester or earlier, and a period of 12 months if taken in the 2025A semester or later. 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.
Chlorine Monoxide (ClO) monitor now at IRTF
The ClO monitor has been installed in the IRTF bunker (the small building at the perimeter of the IRTF site) and is operating as designed.
The ClO monitor is an infrared FTS operating at about 230 Ghz. It measures the abundance of ClO in the stratosphere. ClO is formed when chlorine from man made CFCs reacts with and destroys ozone. Ozone absorbs harmful UV radiation from the sun. Diurnal measurement of ClO is vital to monitor the effectiveness of international treaties put in place to restrict the use of CFCs. To make these measurements the ClO monitor needs to operate at high altitude. Data from the monitor is public and can be found here:
https://ndacc.larc.nasa.gov/instruments/microwave-radiometer