Call for Proposals for the
NASA Infrared Telescope Facility

DEADLINE: Tuesday 01 October 2019

NASA Infrared Telescope Facility Observing Proposals. The due date for the 2020A semester (February 1, 2020 to July 31, 2020) is Tuesday, October 1, 2019. See our online submission form, which is available for proposal submission from 12:00AM on September 01, 2019 until 5:00PM on October 01, 2019 HST. The deadline on a world clock listing is available here.

For up-to-date news about IRTF please read the Newsletter.

Available facility instruments include:

(1) SpeX, 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.

(2) MORIS, 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.

(3) iSHELL, a 1.06 – 5.3 micron cross-dispersed echelle spectrograph (up to R=80,000) and imager. We plan to install K-, L- and M-band order sorting filters in August 2019. We hope that wedging the filters will remove one source of fringing seen in the flat fields. (A lower amplitude and variable frequency fringing due to the immersion grating is more problematic.) 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.

(4) MIRSI/MOC, a 5 – 20 micron camera and grism spectrograph and optical imager. 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.

Information on available instruments and performance can be found at: Exposure time calculators for SpeX and iSHELL are available on the respective instrument webpages.

PI-led visitor instruments (available on a collaborative basis with the instrument team) include: TEXES (5-20 micron high-resolution spectrograph; contact Tommy Greathouse at for more information) and BASS (3-14 micron spectrometer; contact Jon Mauerhan at for more information).

Following feedback from the IRTF TAC, investigators are asked to make a clear statement about the connection between the proposed observations and the overall science goal. It is important to concisely articulate the big science picture. Be specific about the number of targets needed, and for continuing proposals, what is needed for the program to be considered complete. Figures need to be legible - no small print. Target visibility plots are not required. We encourage proposals that will provide data for thesis work. The student should be listed as PI or at least as Co-I. You will be asked to provide details of the thesis on the proposal form including the anticipated year of graduation.

Investigators are reminded that any significant changes to the TAC approved observing program must be pre-approved by the IRTF Director.

Observers may apply for Target of Opportunity (ToO) programs on IRTF, but the total time that can be allocated to ToO programs is 12 hours for Solar System and 12 hours for non-Solar System proposals. Each ToO interrupt is limited to 3 hours in length. The proposal team must include at least one member that is highly familiar with the IRTF instrument being used, who will be able to carry out the interrupt observations without support from the IRTF staff. 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.

Remote observing is available with SpeX, MORIS, iSHELL, and MIRSI/MOC. Requests for remote observing must be made in the proposal application – later requests will be considered if requested at least one month ahead of time. If you wish to observe from your home institution, you must comply with the requirements for video conferencing and instrument operation provided on the Remote Observers Information page. (A working three-button mouse is required.) Observers are strongly encouraged to contact Miranda Hawarden-Ogata ( to set up a test of the video link and user interface at least one month prior to their observing run. We cannot guarantee a successful remote observing connection on short notice since we have no control of hardware and software compatibility on the user’s side. It is the responsibility of the PI to provide up to date observing contact information through submission of the online Observing Requirements Form (ORF).

To keep our bibliography up to date, and to ensure future funding of the IRTF, we ask that you send us citations to your latest IRTF publications. You can check your publications using our website bibliography page for refereed papers:

Please send any missing references to Bobby Bus (, and please continue to include in your paper the acknowledgement to the IRTF and the name of the instrument used as described at:

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 (

The IRTF Data Archive is hosted by the NASA/IPAC Infrared Science Archive (IRSA) at: 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.