FILM : Far-Infrared Line Mapper

The Far-Infrared Line Mapper (FILM) is a grating spectrometer designed to simultaneously measure (C II) 158 microns and (O I) 63 microns line intensities and continuum emission near the (C II) line with spatial resolution of 8 arcmin. Very high sensitivity and accuracy are achieved by using stressed and unstressed Ge: Ga detectors at 1.8 K with a helium cooled telescope and by using a spectral scanner to distinguish the line emission from the continuum emission. Line intensities of the (C II) and the (O I) will be mapped over 10% of the sky with much higher sensitivity than the previous survey measurements.


Size 250 x 150 x 130 mm
Weight 1950 g
Grating a varied line-space cylindrically concave grating
Beam size (FWHM) 8' (dispersion direction) x 13'
Area to be observed 10-20% of the sky

Channel 1 2 3 4
Band Center (cm-1) 64.4 63.4 62.4 158.4
Resolving Power 130 409 130 405
Detectors stressed Ge:Ga stressed Ge:Ga stressed Ge:Ga Ge:Ga
Optical through-put 0.34 0.30 0.34 0.15
S (detector) (A/W) 10.1 11.1 9.7 0.51
System NEP (10-16 W/Hz1/2) 1.8 0.60 1.7 12

Photograph of the FILM

FILM Archive Data Executive Summary

Data Number12
Data155 mm Continuum[CII] Line
Band Centercm-164.463.4
Resolving Power130(409)
Beam Size (FWHM)8'x13'
(scanning direction)x(cross-scanning direction)
System NEPW Hz-1/21.8x10-166.0x10-17
TargetContinuum[CII] Line
RMS Noise
(without stripe noise)
in nInW m-2 sr-12x10-7
in InMJy sr-110
Uncertainty in Zero Level
(including stripe noise)
in nInW m-2 sr-16x10-7
in InMJy sr-130
Uncertainty in Intensity Scale-19% to +26%
Pixel Size4'x4'4'x4'
Number of Pixel192x192192x192
Image Size12.8 deg x12.8 deg12.8 deg x12.8 deg
Uncertainty in Map Position4'-8'4'-8'

For more details, refer to the following documents.

FILM Explanatory Supplement [PDF]

"Flight performance of the Far-Infrared Line Mapper (FILM)"
H. Shibai, T. Nakagawa, H. Okuda, S. Makiuti, H. Matsuhara, K. Okumura, N. Hiromoto, Y. Doi, and T. Tohya
1996, in SPIE Proc.2817, Infrared Spaceborne Remote Sensing IV ed. M. S. Scholl and B. F. Andresen, p.267-275
"Far-Infrared Line Mapper (FILM) on the Infrared Telescope in Space"
Hiroshi Shibai, Masao Yui, Hideo Matsuhara, Norihisa Hiromoto, Takao Nakagawa, and Haruyuki Okuda
1994, The Astrophysical Journal, vol.428, p.377-383

Last Modified: 19 November 2018