Summary of Near-IR results:
		• The lower temperature of the sky and telescope gives at least a factor of 20 reduction in sky background beyond 2.5 mm. • The “cosmological window” from 2.27 to 2.45 mm is a factor of 100 darker, because of a natural gap in the air-glow. • The air-glow drops by a factor of 3 when the Sun is more than 10° below horizon.