1995PASP..107..488P

We have designed and built a re-imaging device for the Caltech Submillimeter Observatory (CSO), which converts the full 10.4m telescope into a small (<1m) off-axis telescope with a 3' beam. The device operates at both 230 GHz and 490 GHz and has allowed us to map large portions of molecular clouds in the ^3P1 -> ^3P0 transition of neutral carbon (v∼225 GHz). The combination of the instrument and the CSO makes available a small telescope with a good surface and minimum blockage and spillover at a high quality site. Because the design avoids having sunlight strike the CSO's primary, we can observe during the day when the full, 10.4 meter telescope is not otherwise usable. Two, two-month seasons with teh instrument have greatly increased our understanding of the large-scale distribution of [C I] emission in the Galaxy.