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-3- The crater Pluto, a dark grey, level floored crater, located on the northern edge of Mare Imbritmi, has had several spots and white streaks reported on its floor. The spots, in some cases, represent craterlets and the streaks, notably two forming a wedge on the south-west corner, have an obscure origin. These spots and streaks are unaccuontably invisible at times when the surroundthg landscape is plainly visible. It has been speculated that "mists" or evolution of gases may cause this phenomenon. Perhaps a rapid temperature change will induce this effect and it may be detected with the aid of a telescope. Another lunar crater of much historical interest is Linne, a small object on the floor of Mare Serenitatis, lying just west of the opening into Mare Imbrium. This diffuse white spot has been reported to change in size during eclipse and a search should be made for this effect. Each area should be studied before, during ard after the eclipse in order to see if any change has taken place. It is iecaiunended that observing the nocn on the evening before the eclipse will provide the necessary familiarization. Seeing conditicris nay render invisible the fine detail in Plato and Linne. All reports of observation of these objects should include the rated seeing conditions, type, size and power of optical equipient and, if possible, drawings or sketches of the area. LUNAR-METEOR WATCH A lunar eclipse affords the best opportunity of observing a meteorite impact on the moon. If such an impact is observed, it is essential that the exact location, direc- tion, time and appearance of the flare be noted, Should the observation be duplicated at another site, it cart be determined whether the flare is truly a lunar phenomenon or whether it is of terrestrial origin, seen against the lunar background. The observer should: (1) be able to judge the location of principal lunar features so as to be able to plot a flare or trail on an available map; (2) in the event of a flare, call out "FLARE" so that the tine can be recorded automatically; (3) immediately plot the location on the map, noting direction and length, if moving; (4) note particularly if it is stationary; (5) estimate duration of flash; (6) note colour and estimate brightness. Theoretical Appearance: A lunar flash may appear as a faint, slwly moving point of light, ending in a burst, listing 2 or 3 seconds. Estimated length of trail - 75 miles or 1/30 of the moon's diameter. Previous reported sightings (unconnmmed) have been described as: "small bright flash, lasting 3 seconds, changing from blue-white to greyish yellow and "bright speck, lasting one second and leaving a glow for perhaps two seconds or more". Recommended Equipment: Two 6" telescopes of sufficient power to cover the required field, lunar map, light source, and prcrcimity to time and tape recorder station. Two observers should search at any one time, for not longer than 15 minutes per watch, then alternating with another team of two, to maintain a high level of efficiency. LUNAR ECLIPSE PHOTOGRAPHY: Enclosed with this bulletin is a special supplement con- sisting of two parts as produced by the Kodak Co. numbered C-20 and M-18, to provide helpful guidance. Reports Iron Centres participating in one or more of the above programmes should be mailed to the writer at the address given below. All results will then be collated and a report on the lunar eclipse obiervations issued to all Centres. Archie L. Ostrander, National Lunar Co-ordinator 74 Brimorton Drive, 12 June, 1964. Scarborough, Ont.