Focal Plane Instruments
ASTRO-F is equipped with two kinds of instruments; the FIS (Far-Infrared Surveyor) for far-infrared observations and the IRC (InfraRed Camera) for near and mid-infrared observations.
FIS : Far-Infrared Surveyor
The FIS is the instrument chiefly intended to make an all-sky survey at far-infrared wavelengths. Two detectors of the FIS are photoconductors which use semiconductor crystal Ge:Ga, Germanium doped with Gallium. Stressed Ge:Ga chips are sensitive to far-infrared light of longer wavelength than normal ones. Each detector is used with filters. Therefore the FIS has effectively four observation bands.
The FIS is also used for pointing observations to detect faint objects or to perform spectroscopy using a Fourier transform spectrometer.
| Band Name | N60 | WIDE-S | WIDE-L | N160 |
| Wavelength(micron) | 50-80 | 60-110 | 110-180 | 140-180 |
| Detector | Ge:Ga | Stressed Ge:Ga | ||
| Array Format | 20x2 | 20x3 | 15x3 | 15x2 |
| Pixel Size(arcsec) | 26.79 | 44.20 | ||
| Pixel Pitch(arcsec) | 29.47 | 49.11 | ||
| Readout System | Capacitive Trans-Impedance Amplifier (CTIA) | |||
| Sampling Speed(Hz) | 25.28 | 16.86 | ||
IRC : InfraRed Camera
The IRC is composed of three independent camera systems. The NIR camera is assigned to near-infrared wavelengths in the 1.7 - 5.5 micron range. The MIR-S camera is assigned to shorter mid-infrared wavelengths over the 5.8 - 14.1 micron range and the MIR-L camera is assigned to longer mid-infrared wavelengths of 12.4 - 26.5 micron.
One of the advantages of the IRC is that it can observe 10 square arcmin at a time because of large format detector arrays (512x412 for NIR, 256x256 for MIR). Each camera can select an specific waveband to observe by using filters. In addition, IRC is equiped with prisms and grisms so it can perform spectroscopic observations.
The observations of the IRC are basically made in pointing mode. Survey observations using a part of detector arrays are also under consideration.
| Camera | NIR | MIR-S | MIR-L |
| Detector Type | InSb | Si:As | Si:As |
| Array Format | 512x412 | 256x256 | 256x256 |
| Field of View(arcmin) | 9.5x10.0 | 9.1x10.0 | 10.3x10.2 |
| Pixel FOV(arcsec) | 1.46 | 2.34 | 2.51x2.39 |
FPI (Focal Plane Instruments) collectively means FIS and IRC instruments
Survey Observation : The ASTRO-F telescope always turns around and sweeps across the entire sky as it orbits the Earth
Stressed : A pressure of 40-60 kgf/mm2 is applied to the detector chips
Pointing Observation : The telescope is kept toward the same location during an observation
micron : one micron is equivalent to one thousandth of a millimeter
Grism : A grism is an optical component which is a combination of a prism and a diffraction grating