Early progress was limited, and it was not until the early 20th century that conclusive detections of astronomical objects other than the Sun and Moon were made in infrared light.
Kemajuan awal cukup terbatas, dan itu tidak sampai awal abad ke-20 bahwa deteksi konklusif dari objek astronomi selain Matahari dan Bulan terdeteksi dalam cahaya inframerah.