The TAO project
To carry out efficient observations at the high altitude of 5640m, the 6.5m telescope is designed (1) to be optimized to the infrared observations, which make best use of the low water vapor in the atmosphere, (2) to be remotely operated from the base facility to avoid harsh environment to human body, and (3) to have high cost-performance. The telescope has 3 foci, to which infrared instruments are installed. The telescope, as well as the instruments, incorporate the cutting-edge technologies to realize observations with the best performance.
The primary mirror is a light-weighted honeycomb mirror, made of borosilicate glass (BSC glass by Ohara, Inc.), developed by Steward Observatory Mirror Lab at the University of Arizona. The mirror, having enough thickness (71cm at the outer edge and 39cm at the inner edge) to sustain its shape, incorporates the honeycomb structure to reduce its weight. The very fast F-ratio of the mirror (F/1.25) contributes to make the the telescope and the dome compact. To realize such a fast shape, the mirror is casted on the rotating table (spin-cast).
To achieve the best performance, the secondary mirror is optimized to the infrared observations which is commonly used for all the foci. As a result, the exchange of the secondary mirror becomes unnecessary and the impact to the operation is reduced. In addition, the latest technology to modify the shape of the mirror surface by high-speed actuators, the deformable secondary mirror, is expected. This function is combined with the adaptive optics system to correct the atmospheric turbulence and provide sharp image quality.
MIMIZUKU: the mid-infrared imager and spectrograph at the Cassegrain focus
As the TAO telescope is located at the high altitude of 5640,
it is expected to have high performance in the mid-infrared wavelength
which is covered by MIMIZUKU (Mid-Infrared Multimode Imager for
gaZing at the UnKnown Universe).
MIMIZUKU has following three features;
(1) fully covering the mid-infrared wavelength from 2 to 38 micron,
(2) spatial resolution of 1 arcsec at 30micron, which is the highest resolution ever achieved, and
(3) achieving accurate relative photometric observation using the newly developed "Field Stacker" unit.
Covering the very wide wavelength range from 2 to 38 micron, MIMIZUKU
takes advantage of the potential of TAO site as the world's best environment for
Also, by putting the Field Stacker System, which is to combine two different
field-of-view into one image, into practical utility for the first time,
it will realize the measurement of high-accuracy temporal variation in the mid-infrared wavelength.
Detailed specifications are available at
SWIMS: Simultaneous two-color MOS spectrograph at the Nasmyth focus
SWIMS (Simultaneous-color Wide-field Infrared Multi-object Spectrograph)
is a near-infrared spectrograph capable of wide-field imaging and
of multi-object-slit (MOS) spectroscopy from 0.9 to 2.5 micron.
With its general-purpose specifications, SWIMS is expected to cover the major part of the scientific objective of the TAO telescope.
It has wide field-of-view of 9.6 arcmin diameter with 0.126arcsec/pix,
and realize simultaneous two wavelength-range (blue arm: 0.9-1.4 micron / red arm: 1.4-2.5 micron) imaging or MOS spectroscopy.
The unique point of SWIMS is its capability to take the spectra of objects from
0.9 to 2.5 micron simultaneously without any break, which makes best use of the continuous atmospheric window in the near-infrared wavelength at the TAO site.
SWIMS consists of the MOS exchanger unit to handle multi-object slits, the main dewar which keeps the optics and the detectors in a cryogenic environment, and support structure to keep the whole instrument in its shape as well as to hold peripheral equipment.
Detail specifications are available at