Transient lunar phenomena
Alphonsus is one of the sites noted for transient lunar phenomena, as glowing red-hued clouds have been reported emanating from the crater. On October 26, 1956, the lunar astronomer Dinsmore Alter noted some blurring of the rilles on the floor of Alphonsus in the photographs he took in violet light. The same blurring did not occur in the infrared photographs he took at the same time. However, few professional astronomers found this evidence of volcanic activity on the Moon very convincing.
One astronomer who was intrigued by Alter's observations was Nikolai A. Kozyrev, from the Soviet Union. In 1958 while Kozyrev was looking for volcanic phenomenon on the moon, he observed the formation of a mist-like cloud within Alphonsus. The spectrum of the area had been measured at this time, and displayed indications of carbon matter, possibly C2 gas. He believed this to be the result of volcanic or related activity. However no evidence for this phenomenon has been found from lunar missions, and the emission results have never been confirmed.