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We have made a submillimeter-wave telescope for a Japanese sounding rocket, -520-17, which is dedicated for an observation of cold dust in Orion molecular cloud region. The submillimeter-wave telescope was launched on January 23, 1995. The telescope include an off-axis Gregorian telescope with aperture of 30cm, focal plane bolometer array, cryogenic cooling system down to 0.3K, and a star sensor using charge modulation device. A very low emissivity optical arrangement of less than 1% is achieved using pure aluminum mirror, off axis reflector and cold optics. Single moded conical feed horn is effectively coupled with bolometers with efficiency of more than 90%. The focal plane array consists of 12-element bolometers, six for 250 micrometers observation and six for 500 micrometers observation. NEPs of the bolometers are 5 X 10-17 W/(root)Hz which is read out by AC bridge read-out circuit. Total system gives sensitivities of about 10-12 W/cm2 (DOT) sr for diffuse objects or 2Jy for compact objects at 500 micrometers over 100deg2 region with a beam size of 10arcmin. This observation should give unique data on cold dust distribution, which is believed to dominate the dust mass distributional, over Orion Molecular Cloud region. Also discussed in the last section is a development of array detectors for future space mission in far-infrared and submillimeter-wave region.
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