Low-frequency measurements of the cosmic background radiation spectrum

The long-wavelength spectrum of the cosmic background radiation has been measured at five wavelengths (0.33, 0.9, 3.0, 6.3, and 12.0 cm). These measurements represent a continuation of the work reported by Smoot and colleagues in 1983. The combined results have a weighted average of 2.73 ± 0.05 K and are consistent with past measurements. They limit the possible Compton distortion of the cosmic background radiation spectrum to less than 6%