Astro F (IRIS, Akari)

Astro F [ISAS]

ASTRO-F, originally named IRIS (InfraRed Imaging Surveyor), is a 70 cm cooled telescope. It has a much more powerful capability for survey work than the IRAS, owing to the advanced technologies now available:

• ASTRO-F covers wide wavelength range from K-band to 200 µm. ASTRO-F will perform an all-sky survey at wavelengths > 50 µm using high-sensitivity Ge:Ga detector arrays. In the near- and mid-infrared ranges, large-format arrays are employed for a deep sky survey in selected sky regions.
• The sensitivity of ASTRO-F is much higher than that of the IRAS. For example, the ASTRO-F has 50-100 times higher sensitivity at 100 µm and more than 1000 times at mid-infrared wavelengths.
• ASTRO-F has a diffraction-limited angular resolution at wavelengths longer than 10 µm. The pixel sizes of ASTRO-F are less than 1 arcmin even at 100-200 µm, several times smaller than the beam of the IRAS.
• ASTRO-F has capabilities for low-resolution spectroscopy. In the near- and mid-infrared ranges, spectroscopy using prisms is available. The Fourier-transform spectrometer is used for the wavelength range from 50 to 200 µm. This capability is very important for classification of sources detected in the deep survey, rough determination of the redshift, etc.

After launch, Astro F received the name Akari.