NASA IRTF Spring 2019 News

Last updated 21 May 2019

2019B Call for Proposals

Proposal Deadline for Semester 2019B (August 1, 2019 to January 31, 2020) is Monday, April 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 will also be here within the next few weeks.

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.

In Spring 2019 we plan to introduce automated quick-look extractions (no telluric division or flat fielding) of newly obtained SpeX spectra that can be inspected in the Data Viewer (DV) on the VNC desktop while the observer is taking data. This real-time assessment of data quality and achieved signal-to-noise values will help observers better plan their observing time.

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.

Telescope Allocation Committee
The current TAC members for non-solar system proposals are: Máté Adamkovics (Clemson University), Katelyn Allers (Bucknell University), and Harriet Dinerstein (University of Texas at Austin), and for solar system proposals are: Lori Feaga (University of Maryland), and Driss Takir (USGS). Lisa Prato (Lowell Observatory), Constantine Tsang (SwRI), and Bin Yang (ESO Chile) rotated off the TAC effective 2019B. Two new members for solar system proposals and one new member for non-solar system proposals are TBD. 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(Spectral Library). An extended spectral library including non-solar metallicity and hotter stars observed by Alexa Villaume and collaborators is now available: Extended Spectral Library . 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 smass.mit.edu/minus.html.


IRTF News

Staffing:
We welcome three new members to the IRTF staff. Greg Engh joined the IRTF in September as a full-time Telescope Operator. Greg fills the vacancy left by Eric Volquardsen who moved to the mainland in May 2018. In November, Theodora ‘Thea’ Reguigne began working as the new IRTF Mechanical Engineer, taking over for Morgan Bonnet. Thea is based at the IfA headquarters building in Manoa. Last but not least, Bernie Walp joined the IRTF staff in January as a Research Associate. Bernie’s time will be divided between working as a Telescope Operator and working on other support duties such as writing documentation.

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.

On Dec. 1, 2017 we announced that raw IRTF data files for the years 2001 to 2016 would be made available on request following a proprietary period of 18 months. It is planned that starting in June 2019, these IRTF "legacy" data will be searchable via a web page, and data files will be downloadable via a script generated by the webserver.

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

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 will be scheduled for early in the 2019B semester.

Instrumentation Update

SpeX:
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:
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:
iSHELL is a 1.06 – 5.3 micron cross-dispersed echelle spectrograph (up to R=80,000) and imager. Wedged order-sorting filters are being procured to remove slight fringing in the spectra. We expect to install these new filters covering the K-, L- and M-band modes during scheduled iSHELL downtime in April 2019. 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 (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 now automatically generated. For more information, see the iSHELL instrument page or contact John Rayner.

MIRSI/MOC:
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. During lab testing, the science-grade array was found to no longer be functioning. When MIRSI is returned to the telescope (estimated for later this semester), it will have an engineering-grade array installed, and will be operated in that mode until a higher-grade array can be obtained. We are currently in negotiations to get a science grade device. Because MIRSI has yet to be recommissioned on the telescope, we will continue to offer MIRSI in shared risk mode during the 2019B 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), 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 anticipated in late 2019. For more details contact Mike Connelley or John Rayner.