NASA IRTF Fall 2024 Newsletter

Last updated D MMMM YYYY

Proposal Deadline for Semester 2025A (February 1, 2025 to July 31, 2025) is Tuesday, October 1, 2024, 5PM Hawaii Standard time.

Please review the information and use our ONLINE application form

Available instruments are listed here. Remote observing is offered from any location with broadband Internet access for any project that utilizes IRTF facility instruments. Click here for more information.

Fall 2024

Help Keep Our Publications List Current

Please continue to acknowledge the IRTF in your publications following the instructions shown here. 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:

Please send any missing references to Bobby Bus (

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

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 ( 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

IRTF Data Reduction Update

As of June 2021, IRTF observers have the option to reduce their SpeX and iSHELL data remotely, on a dedicated IRTF computer. 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. 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. Xtellcor_model also includes a method to correct the iSHELL echelle order curvature using flat fields. This typically leaves more instrumental artifacts than when using standard stars, and observers should keep planning to take standard star spectra until they have verified that Xtellcor_model satisfies the calibration needs for their science programs.

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 ( for requests and questions about the reduction of IRTF data.

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: