"Giant leap in lunar knowledge"
Lunar Section Report - News Circular 200 - Nov 1997
The first issue of the News Circular appeared in November 1966 and featured photographs from the US Lunar Orbiter 1 probe. Without the Lunar Orbiter programme our satellite would have remained inadequately surveyed, because the Soviets had no equivalent programme. In 12 months following August 1966, five successful mapping probes were sent into lunar orbit with the intention of mapping the surface to a high resolution. This assisted the selection of potential landing sites for both Surveyor and Apollo. At the end of the programme, Lunar Orbiters 1 to 5 had mapped 99 percent of the Moon to an exquisite degree.
From 1964-65 the US Ranger probes 7, 8 & 9 all crashlanded on the Moon, returning close up pictures of the lunar surface during their terminal descents. When News Circular 1 appeared, only two spaceprobes had successfully softlanded on the Moon - the Soviet Luna 9 in January 1966, which landed in Oceanus Procellarum (Ocean of Storms) west of the crater Reiner to return panoramic pictures, and US Surveyor 1 which touched down in May 1966, also in Procellarum, north of the crater Flamsteed. On Christmas Eve 1966 Luna 13 landed in the Ocean of Storms and returned superb 360 degree panoramic views and showed objects in the lunar soil particles down to 1.5 mm.
The success of these first softlanders proved to most people's satisfaction that the Moon's surface was sturdy enough to withstand the landing of a manned lunar module and support the weight of spacesuit-clad astronauts. Some had seriously imagined that the lunar surface might in places be covered with dangerous drifts of lunar soil that might engulf manned spacecraft like quicksand. Indeed, many were still sceptical that NASA could successfully land humans on the Moon before 1970. Even Michael Collins, Command Module Pilot of Apollo 11, estimated the chances of his mission's success at just 50/50!
When the News Circulars appeared, exciting things were happening in all areas of astronomical research. From a lunar perspective, spaceprobes and manned exploration promised to determine the global geography of the Moon, its mineral composition and the nature of the surface. Analysis of Moonrocks would shed new light on the formation and history of the Moon and the processes that shaped its surface.
In 1966 the debate on how the Moon's craters were formed was still rumbling, though the tide had long turned in favour of meteoroids and asteroidal impacts as the main cause of lunar craters. The volcanic hypothesis had begun to fall out of favour decades before. Two years before, the US spaceprobe Mariner 4 had returned 21 photographs of Mars, revealing spectacular impact cratering evidence on the planet.
Despite the enormous gains in knowledge, much of it reported in the Circulars, each answer to the puzzle of the Moon raised more questions. The Clementine probe mapped the Moon fully in 1994, revealing much about the mineralogy of our satellite's surface and even hinting at the presence of water ice within perpetually shadow-filled lunar south polar craters. The Lunar Prospector probe will take up Clementine's baton and give us an excellent detailed map of the entire Moon - the last great unmanned mapping project prior to our physical return to the Moon early next century.
In 1839 Francois Arago referred to the potential of the new technique of photography in mapping the Moon. Speaking to the Chamber of Deputies in Paris Arago said "We may hope to make photographic maps of our satellite, which means that we will carry out one of the most lengthy, most exacting and most delicate tasks of astronomy in a few minutes." He meant that photography promised to instantly dispose of the labours involved in visual Moon mapping at the eyepiece, and all the inaccuracies and ambiguities that method introduces. Arago's prophesy may well be realised before SPA News Circular 250 appears.
Now to briefly report on section activity, concentrating on the total lunar eclipse of 16 September. The eclipse was observed well, even though the Moon rose in Britain during mid-eclipse and was very low as it came out of the umbral shadow. I made a video of the event, but thin cloud tended to hamper my view from time to time. Lee Macdonald (Newbury) observed from 19h 50m to 20h 50m and noted a slight orange-red umbra with a blue tinted band just inside the umbral edge. Lee also noted the fainter penumbral shadow. Shelagh Godwin observed from the Dordogne in France, and sent in a description of the appearance of the eclipsed Moon. She noted "At 19h 02m...the upper three-quarters were coppery-grey, darkest towards the top, quite pale towards the bottom quarter which was light grey." Ian Phelps (Warrington) observed with 10x50 binoculars and made a sketch showing the shadow position at 19h 52m. His observation was made difficult because of a layer of haze, cloud and a little rain during the observing session. Finally, Grahame Wheatley (Long Eaton) observed between 19h 23m and 20h 25m through 12x50 binoculars, and sent in two disk drawings.
Note: To those who have contributed drawings recently, a full report containing details of individual members' "regular" lunar observations will appear in the next News Circular.
