ハーシェル宇宙望遠鏡
Source counts were important tasks for the recent infrared missions like 2MASS or the Infrared Space Observatory (ISO), and is still one of the most important questions the current and near future infrared space instruments (the Spitzer Space Telescope and the Herschel Space Observatory). While ISO was able to resolve about 3–10% of the total CIB light into individual sources (depending on the wavelength), Spitzer measurements have already detected ~30% of the CIB as sources, and this ratio is expected to be ~90% at some wavelengths with the Herschel Space Observatory.