A mysterious lunar phenomenon has been baffling observers for centuries.
Transient lunar phenomena (TLPs) are the short-lived changes in the brightness of areas on the surface of the moon, appearing as bright flashes, with some lasting seconds and also some lasting for hours!
These can be various colours such as flashes of red, violet, green or blue, some also have been recorded as ‘darkening’s.’ There are also descriptions of hazes or mists.
With the first telescopes came more regular reports of TLP’s including sightings recorded by the famous astronomer William Herschel. In April 1787 he reported that he had spotted three red glowing spots on the dark side of the moon. Herschel was so determined that he seen these that he even had King George III come to try and see them through his telescope.
From then there have been a vast number of recorded sightings by both amateur and professional astronomers.
A catalogue of sightings was made by NASA before the Apollo 11 mission.
In the early days of the Apollo programme NASA commissioned a research project into TLP’s but avoided the use of the term. Instead they called this endeavour Project Moon-Blink, its goal was to try to discover more about ‘unusual colour occurrences’ on the Moon and if they really occurred. Within their findings they confirmed the occurrences of red colourations on the moon surfaces some occurring for several hours. An example of this being the Trident sighting on 15 November 1965 where the coloration was observed for a few hours and may have lasted longer but the sunrise cut observations short.
579 lunar events were catalogued from 1540 until 1967.
The astronauts in the Apollo programme observed certain occurrences of their own. In 1969, whilst circling the moon Houston radioed Apollo informing them of an observation of a TLP that astronomers in Germany had observed in the region of Aristarchus on the Moon. The Apollo crew checked it for themselves and reported back stating;
“Hey, Houston, I’m looking north up toward Aristarchus now, and there’s an area that is considerably more illuminated than the surrounding area. It seems to have a slight amount of fluorescence.” NASA, Apollo 11 Transcripts
When all the 579 official TLPs were recorded, It was curious that a third of these were observed in the vicinity of Aristarchus crater on the north-west part of the Moon’s near side.
Wandering the Labyrinth 