Fall 2011 News
Last updated 1 September 2011
Proposal Deadline for Semester 2012A (February 1, 2012 - July 31, 2012) is Monday, October 3, 2011, 5PM Hawaii time.
Available instruments are listed here. Remote observing is offered from any location with broadband Internet access for any project that utilizes IRTF instruments. Click here for more information.
Telescope Allocation Committee
The current TAC members are Thomas Greathouse (Southwest Research Institute), Michael Gregg (Lawrence Livermore Nat. Lab.), Susan Lederer (Johnson Space Center), Kevin Luhman (Penn. State), Andy Rivkin (Johns Hopkins Applied Physics Lab), and Kris Sellgren (Ohio State Univ.). This committee consists of three solar system and three non-solar system members. The members who rotated off are Mark Buie (SWRI) and Tracy Beck (STScI).
Science Highlights and Publications
Our Science Highlights page is updated regularly as we receive the latest highlights from you. These highlights are sent to our funding agencies, NASA and NSF, to keep them abreast of the exciting and useful science obtained at the IRTF. See examples here. Please 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. For AAS publications, please include the facility keyword and instrument, such as IRTF:SpeX.
Please help us update our bibliography by checking your publications against our list of refereed and unrefereed publications at:
Please send any missing references to William Walters
Non-standard Observing Programs
We have a program to observe Titan whenever it is up and SpeX is on the telescope "Titan's Methane Meteorology: Context for Cassini Titan Flybys T63-T66" (PI: E. Schaller). This program is aimed at discovering new cloud features on Titan (see the Press Release). If there is evidence for activity, then adaptive optics imaging is obtained at the Gemini or Keck observatories. The observing time is noted on the schedule and there is flexibility on when the observations are taken.
IRTF Spectral Library
Users are encouraged to make use of the spectral library, which is available here. The papers on Cool Stars are published and are available here: The Infrared Telescope Facility (IRTF) Spectral Library: Cool Stars and An Infrared Spectroscopic Sequence of M, L, and T Dwarfs . Contact John Rayner for more details.
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.
One millimeter is not much for most people, but for IRTF Mechanical Engineer Morgan Bonnet it makes a big difference when designing astronomical instruments that are built to tolerances within a thousandth of an inch. Bonnet started working for the IRTF in March of 2010 and was immediately put to work designing a secondary mirror cover. The IRTF has two secondary mirrors that are periodically changed out depending on the needs of the observers. The day crew needed a handy and secure way to safely remove the mirror form the telescope and store it. Bonnet's work involved interviewing the day crew to discuss their needs and researching how the mirror is handled and attached to the telescope.
Then Bonnet created the mirror cover design using a CAD program and printed the results that were then reviewed then double checked and triple checked for measured accuracy before being sent to IfA's in-house machine shop for final fabrication.
The results of his labor were immediately appreciated by the day crew who no longer had to worry about accidents while handling the mirror during change outs.
Bonnet's primary duties at the IRTF are to work on designing the cryogenic mechanisms within the iSHELL instrument. Bonnet obtained his mechanical engineering degree in France at the French Institute for Advanced Mechanics (IFMA) and first came to Hawaii by way of six-month internship at the Hawaii Natural Energy Institute where he researched lithium batteries for hybrid vehicles. Bonnet also worked in the automotive industry developing high-efficiency diesel injection systems.
Bonnet said the biggest challenge of working at IRTF are the critical design decisions that go into making the iSHELL instrument. Bonnet said that developing the iSHELL involves merging the optical and mechanical designs together taking into account thermal and operational constraints and making sure the mechanisms can be controlled with an efficient and reliable strategy. The biggest challenge is also the biggest reward when you see it all come together Bonnet said.
When Bonnet is not designing instruments for the IfA, he enjoys all the outdoor activities that Hawaii is famous for including surfing, sailing and hiking.
SpeX is a 0.8-5.5 micron Medium-Resolution Spectrograph and Imager and continues to be the most popular instrument at the IRTF. We anticipate that SpeX will be taken offline on February 1st, 2013 and will be unavailable for the entire 2013A semester (Feb. 1, 2013 - Jul. 31, 2013). This is necessary to upgrade SpeX with new arrays and array controllers. The delay of one semester in SpeX downtime has become necessary to build and test the new array controller. We strongly recommend observers to plan their observing accordingly. We also expect to accomodate key projects requiring large amounts of observing time using CSHELL, NSFCAM2, MIRSI, and visitor instruments. For more information on SpeX contact John Rayner for all the details.
The MIRSI instrument continues in its powerful role as one of the few 10 micron cameras available for planetary science. It has been used to study asteroids, comets and the weather patterns on Saturn. This instrument is currently on loan to the IRTF from Boston University, and much effort has been made to optimize its use at the IRTF. Software engineer Charles Lockhart created a graphic user interface so that it is controlled much like the rest of the IRTF's facility instruments. The IRTF's instrument technicians also performed an overhaul on MIRSI to optimize its liquid Helium consumption. For more information on this instrument's capabilities contact Bobby Bus.
Due to delays in the array controller development, we are planning to take NSFCAM2 offline on Feb. 1, 2012 to install a new infrared array. We expect it to be available starting in semester 2012B (Aug. 1, 2012 - Jan. 31, 2013). Due to the schedule uncertainties, proposals to use NSFCAM2 will be accepted provided the program can be also accomplished with the SpeX slit viewer which has a 0.12"/pixel and a 60"x60" field of view. For more information on when it will be returned to service please contact Michael Connelley.
This is a 1-5.5 micron high-resolution echelle spectrometer. CSHELL has an ongoing observation program that uses a pioneering gas absorption cell in order to conduct the detection of exoplanets. Use of this technology will assist IRTF to identify what level of accuracy is needed in the development of the next generation of near-infrared spectrographs such as the iSHELL instrument that is currently under fabrication. Contact John Rayner for more details. Contact John Rayner for more details.
The design of the iSHELL instrument continues. A design team including mechanical engineers Gary Mueller and Morgan Bonnet have very busy working under the direction of lead instrument engineer Tim Bond to bring the various components into one cohesive package. Mueller has been tasked to create the conceptual design for the cross-disperser grating and image rotator mechanisms while Bonnet has been tasked with the conceptual design of the filter, slit, and immersion grating changing mechanisms. As the lead instrument designer, Bond is creating the optical bench and fitting the rest of the components into a very compact package. Preliminary CAD drawings show that the final dimensions of the instrument will be smaller than the SpeX instrument. This is ideal for two reasons, Bond said, first because it will be easier to keep cool, and secondly the whole instrument will be less susceptible to flexure.
While the mechanical drawings are reaching completion, lead electronics engineer Peter Onaka is spearheading the effort to fine tune the IRTF Stargrasp array controller, which will eventually control all of information gathered by the iSHELL's infrared detector array. Once complete the IRTF Stargrasp controller will debut on the NSFCAM2 Instrument where it will be fully optimized before being deployed on the iSHELL Instrument.
The MIT Optical Rapid Imaging System (MORIS) is based on an Andor iXon 897 (512x512 pixel) camera, which has high quantum efficiency over the visible wavelength range (> 90% from 480 - 700 nm), low read noise (~6 e-/pixel in conventional 1-MHz readout), low dark current, and the capability to operate in electron-multiplying mode. The camera is thermoelectrically cooled. In addition, MORIS consists of a foreoptics box mounted to the side-facing, dichroic-fed window of the SpeX cryostat (60"x60" field of view), and a GPS unit that can provide external triggering of exposures to several-nanosecond accuracy. A 10-slot filter wheel currently contains Sloan g', r', i', z', Johnson V, VR, two long-pass-red filters, an open slot, and one position that is reserved for a visitor filter (1" round). The Andor camera can be operated under either the Windows platform using the vendor supplied Solis program, or under Linux using an IRTF-standard GUI and data viewer (DV). When using the IRTF GUI, MORIS can be controlled simultaneously with SpeX through a single command-line macro, and MORIS provides the option for use as a visible-wavelength guider for SpeX. MORIS has been a PI instrument (PI - Amanda Gulbis, MIT and SAAO/SALT), but we are now making MORIS available to the general IRTF user community. For more information about MORIS, contact Bobby Bus.
Jumps, and things that go bump in the night:
After 30 years of operation some of the devices that move the telescope are beginning to wear. For example, after weeks of smoothly tracking objects in the sky the telescope will periodically "jump" without warning. Although these jumps are rare and affect few observation programs, staff Astronomer Michael Connelley has painstakingly analyzed recordings of these events and has developed a systematic plan to identify the cause. The plan calls for the use of 8 accelerometers stationed at key locations behind the secondary mirror. The goal is to observe which accelerometers record a jolt during a jump, and which don't in order to isolate the source of the jumps. Connelley estimates that it will require a month of data collection with computer time stamping while the telescope is tracking objects in the sky before a clear determination can be made.
In addition to the jumps occasionally the telescope's dome will refuse to move. For years telescope mechanic Sammie Pung has been able to make magical adjustments to the dome rollers and various moving parts to keep things moving smoothly. Lately these fixes seem to be less effective, and the dome has periodically burned out its control motors. A consultant from Geo Tech Industries has been called in to assist IRTF engineers to quickly identify a solution. Aside from making the dome move smoothly, their preliminary analysis suggests that modernizing the dome's motors and electronic controllers may be required. Currently the dome uses three modestly powered DC motors with an older design that utilizes brushes making them susceptible to overheating. These motors could be replaced with modern powerful brushless motors that are less susceptible to over heating and use sturdy permanent magnets to generate more speed and torque.