mountain profile Institute for Astronomy University of Hawaii

Instrument Development

Maintained by W-W

All the major instruments on the University of Hawaii's own telescopes (the 2.2-meter on Mauna Kea and the Mees Observatory on Haleakala) were built in the workshops of the Institute for Astronomy. So, too, were the cameras and spectrographs used on the 3-meter Infrared Telescope Facility (IRTF) that the IfA operates for NASA on Mauna Kea.

AEOS spectrograph

wpeB.gif (56188 bytes)The IfA has designed and is currently completing construction and testing of a sophisticated optical/infrared echelle spectrograph for the 3.67 m AEOS telescope operated for the Air Force on Haleakala. The infrared arm uses as its detector a Rockwell 2048 x 2048 pixel HAWAII-II array developed specifically for this project. The optical arm uses two 2048 x 4096 Lincoln Labs CCD arrays. Both arms of the spectrograph give resolutions of; 20,000 to 50,000, depending on the slit used.

While improvements in the software and controls for the optical arm of the spectrograph are ongoing, the first useful scientific observations were obtained in a campaign to study active M star flares. The infrared arm of the spectrograph will be ready for operation in early 2002. The instrument is being built by Jeff Kuhn, Klaus Hodapp, Gerry Luppino, Alan Stockton, and graduate student Bob Thornton. As a fixed instrument with long-term dedicated access, this facility will have unique scientific impact for many stellar research projects

CFHT WIRCAM Detector Development

The Canada-France Hawaii Telescope Corporation has now formally started a project to build a wide-field 4096x4096 near-infrared camera for the prime focus of the CFHT. The project was initiated by a series of design studies by Klaus Hodapp for CFHT and now has the support of all CFHT partner communities. Two additional partner countries, Taiwan and Korea, have joined specifically to support WIRCAM. The project has been divided up among the CFHT partners; the mechanics will be designed and fabricated in France, the optics in Canada, and the detector system in Hawaii, with participation by Taiwan. The detectors will be identical to the multiplexer design being developed for Next Generation Space Telescope (NGST), but the detector material will have a cutoff wavelength of 2.5 microns.

UH Wide-Field Imager UH-WFI)

UHWFI is a project led by Klaus Hodapp to build a large focal reducer system for the UH 2.2m telescope. It is funded by the National Science Foundation (NSF). In conjunction with the refurbished and modernized UH 8K CCD camera, it will give the UH 2.2-meter telescope the capability to use its full unvignetted field of 30 arcminutes, a capability that has not been available since photographic plates became obsolete. Both the CCDs in the new UH 8K and the optics in UH-WFI will be optimized for the long wavelength end of the optical spectrum .

Instruments for the NASA's Infrared Telescope Facility (IRTF)

The IfA is responsible for the operation and maintenance of the IRTF. A major function is the construction and facility instruments. These instruments are built by the IRTF staff using funding from NSF. Instruments that have been built at the IRTF include NSFCAM (a 1-5 micron camera), CSHELL (a high-resolution spectrograph), and SpeX (a moderate-resolution spectrograph). The IRTF is currently building a 36-element adaptive optics system that will be operational in 2002.

Instruments on IRTFThe facility instruments at the IRTF are mounted onto the back of the primary mirror cell and are typically left on the telescope all the time except when they are removed for maintenance. The instrument complement at the IRTF is shown on the left the photo on the right shows the cryogenic optics of SpeX, a 1-5 micron spectrograph.

SPEX instrument Current infrared detectors for astronomy are so sensitive that it is necessary to cool the instrument to eliminate the infrared radiation it produces. The instrument optics are cooled with liquid nitrogen and are at about 75 K, while the  instrument detectors are cooled with closed-cycle coolers and operate at a temperature of 30 K.    To accomplish this, all of the optics are enclosed in a vacuum jacket.   Specialized techniques are used for mounting optics and for construction of cryogenic mechanisms (such as filter wheels, grating position changers, and focus mechanisms).

ArrayOne of the areas of excellence of the IRTF is the development of infrared array controllers.  Current astronomical infrared arrays in use at the IRTF utilize 1024 x 1024 element arrays that are sensitive from 1 to 5 microns.  A single astronomical-grade array of this type costs about $250,000.  The array controller, which is needed to read out the array very quickly, costs nearly as much.  The detector array and the controller are amongf the most important elements of the infrared instrumentation.  A photo of an infrared detector array installed in its cryogenic mount is shown on the left.