The Sun in Submillimeter and Near-Millimeter Radiation

We examine the best solar submillimeter observations made on the James Clerk Maxwell Telescope in 1991 and 1992. In these observations, the solar disk was observed concurrently in pairs of wavelengths chosen from 350, 850, and 1200 μm. Images at all of these wavelengths show clear limb brightening of the quiet Sun. The observations clearly resolve the chromospheric supergranular network in active and quiet regions. The quiet Sun is characterized by large-scale variations in brightness, particularly the occasion of anomalously dark regions that tend to surround active regions. Sunspots are clearly resolved, with large dark umbrae clearly distinguished from sometimes particularly bright penumbrae.