NASA IRTF Fall 2019 News

Last updated 02 September 2019

It's the IRTF's 40th Anniversary!
The IRTF was dedicated on July 6, 1979. July 2019 marks the IRTF's 40th Anniversary. Read the press release 40th Anniversary of NASA's Infrared Telescope Facility.

Twenty-fifth Anniversary of SL-9 Jupiter Impact
We're also celebrating the 25th anniversary this July of the IRTF campaign to observe the spectacular impact of comet SL-9 with Jupiter: How Historic Jupiter Comet Impact Led to Planetary Defense.

Maunakea Observatories Update
Due to protests over the construction of TMT activists prevented access to all Maunakea Observatories for four weeks starting July 16, 2019. Current access is via the spur road (see map) since the Maunakea Access road is blocked by the activists to prevent transport of TMT equipment to the summit. Access via the spur road is far from ideal and we do not consider it safe. We are therefore recommending that all IRTF observations be done remotely unless there is an overriding need to observe from the telescope (e.g. for visiting instruments) until the situation is resolved.

2020A Call for Proposals

Proposal Deadline for Semester 2020A (February 1, 2020 to July 31, 2020) is Tuesday, October 1, 2019, 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.

IRTF Future Directions Workshop Update
We held a very successful workshop on the future of IRTF at the Biosphere 2 facility near Tucson on Feb 12-14, 2018. Input from the workshop is being used to explore possible future directions, to prepare white papers for input into the upcoming planetary and astrophysics decadal reviews, and to inform plans through and beyond the lease that ends in 2033 for operations of all the Maunakea telescopes. Workshop presentations are viewable here. The white papers resulting from the workshop are posted here.

Telescope Allocation Committee
The current TAC members for non-solar system proposals are: Katelyn Allers (Bucknell University), Harriet Dinerstein (University of Texas at Austin), Melissa McClure (University of Amsterdam), and Alan Tokunaga (University of Hawaii), and for solar system proposals are: Mark Bullock (Southwest Research Institute), Katherine de Kleer (Caltech), Mário De Prá (University of Central Florida), and Lori Feaga (University of Maryland). Máté Adamkovics (Clemson University) and Driss Takir (USGS) rotated off the TAC effective 2020A. If you are interested in serving on the IRTF TAC please contact John Rayner.

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.

IRTF Spectral Library
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.

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

NEO Spectral Survey
The MIT-IRTF Near-Earth Object spectral survey is underway, and many spectra are publicly available. See the side bar for more information or go to

IRTF Data Reduction Update
We have developed a version of Xtellcor (named Xtellcor_model) that uses atmospheric models instead of standard stars to remove telluric absorption lines in iSHELL spectra. A beta version of 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. We are currently improving the automated fitting algorithm. Xtellcor_model also includes a new method to correct the iSHELL echelle order curvature using flat fields. This typically leaves more instrumental artifacts than when using standards 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.

We have implemented “quicklook” reduction of SpeX spectra. 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 are 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 quicklook. We are currently working on a similar implementation for iSHELL.

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 us (Adwin Boogert) for requests and questions about the reduction of IRTF data.


Observatory Manager, Imai Namahoe, is planning to retire at the end of 2019. Imai is family and has been at IRTF since 1986. We will miss him. The hiring of a new Observatory Manager will commence soon. One of the day crew is currently on long term medical leave and we are in the process of hiring a temporary replacement. An electronic technician to replace the position originally occupied by Imai is also being hired.

IRTF Data Archive:
The IRTF Data archive is now open for use, and is being hosted by the NASA/IPAC Infrared Science Archive (IRSA). 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. 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.

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.

Further information can be viewed on the IRTF Data Release Policy page.

Hour Angle Drive Problem
The telescope hour angle (HA) drive was serviced in March 2019 to track down the source of unexpected noise. The drive is original and 40 years-old and so this was done as a precaution. Several bearings were replaced but following reassembly telescope HA tracking occasionally starts oscillating. This is fixed by adjusting the telescope balance and little observing time is being lost (typically 5 minutes per night) but the problem is a puzzle that we are trying to resolve. We had a meeting with outside experts from CFHT in June that resulted in a recommended series of tests that are currently underway. Engineers from the HA drive vendor are also planning to visit once we can guarantee access to the summit.

New Moveable Counterweights:
With the addition of iSHELL it is currently not possible to balance the telescope for all combinations of facility and visitor instruments stowed on the multiple instrument mount (MIM), reducing scheduling flexibility. To correct this, two new moveable counterweights, each weighing 1000 kg, are being fabricated. Installation of these counterweights will require a few days of telescope downtime that are scheduled for January 2020. However, this might be delayed until we understand and fix the HA drive problem.

Instrumentation Update

SpeX is a 0.7-5.3 micron medium-resolution 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. Electronic observing logs are now automatically generated. For more information see the SpeX instrument page or contact Mike Connelley.

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. Electronic observing logs are now automatically generated. For more information see the MORIS instrument page or contact Bobby Bus.

iSHELL is a 1.06 – 5.3 micron cross-dispersed echelle spectrograph (up to R=80,000) and imager. Wedged K-, L- and M-band order sorting filters were installed in August 2019. Unfortunately these did not remove the fixed spatial frequency fringing seen in flat fields as hoped. The source of these fringes is not understood. The fringes can appear in data due to slight flexure in the instrument. More frequent flat fielding should help reduce the amplitude - see the online manual. (A lower amplitude and variable frequency fringing is due to the immersion grating.) Fringing is usually only apparent at S/N>100. Commissioning observations involving radial velocities have yielded good results, with precisions better than 10 m/s achieved for targets brighter than K=10. Thus beginning 2019B, we are no longer limiting the number of proposals requiring higher precision radial velocities. The RV data reduction code is available on github or by request from Peter Plavchan ( 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 now automatically generated. Observers are reminded that darks are automatically taken following observing and can be downloaded. For more information, see the iSHELL instrument page or contact John Rayner.

MIRSI is a 5 – 20 micron camera and grism spectrograph. Due to operational reasons MIRSI now uses a ZnSe window, limiting the long wavelength cutoff to 20 microns. MIRSI was recently upgraded by IR Labs with a closed-cycle cooler to replace its liquid nitrogen and liquid helium cryostat. It is currently undergoing further refurbishment by IRTF staff with a new array controller and addition of an optical channel similar to MORIS (MOC) with a 60"x60" field-of-view. Unfortunately fixing read out problems is taking much longer than anticipated. The original science grade array no longer works but we are about to take delivery of a science array being loaned to IRTF from Gemini and which was originally used in T-ReCS. Because MIRSI has yet to be recommissioned on the telescope, we will offer MIRSI in shared risk mode during the 2020A semester. A new chopping secondary mirror should also be available for use with MIRSI. Remote observing will be available with MIRSI and MOC. For more information see the instrumentation page of the website or contact Mike Connelley.

Proposed New IRTF Facility Instrument:
SPECTRE (Spectrograph Express) is a R=100 0.4-4 micron 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 2.4-4.0 micron, and the integral field unit has a ~6x6 arcsec FOV to remove slit losses and to acquire absolute photometry on point sources. Object acquisition and guiding is done with a 3 arcmin FOV CCD. There are no cold mechanisms, facilitating easy and once-per-night calibration. The preliminary science case and instrument concept was presented at the IRTF’s Future Directions Workshop in February, 2018. SPECTRE received strong support from the workshop participants. High priority science cases include: the characterization of NEOs and small bodies, measuring fundamental stellar parameters (Lbol and Teff) and characterizing exoplanet hosts, optical-IR transient follow-up and variability, ISM dust and ice studies through stellar extinction measurements, spatially resolved spectroscopy (binaries), occultation spectroscopy, and spectral-spatial mapping of ice and dust in comet comae. IRTF staff are currently working on a detailed design in preparation for a funding proposal to NSF anticipated in fall 2019. For more details contact Mike Connelley or John Rayner.