Arizona republican., 1901-06-11
HOOKING DQWNWARDS
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 synchronize the movement of the mir TOT to follow the course of a particular 1 star quite as easily as he may shift it's { position to bring any portion of the heavens in the field of view.
 The mirrors, lenses and machinery of the telescope were all taken from Cam bridge early in October, but nearly three months were spent in the work of getting ready. so that it was not until the morning of the first day of the new century,\a few minutes after midnighr. that the first observations were made. and several days later before satisfae- tory photographs were obtained. The twelve-inch lens i. used with a stop reducing 1t to siX-inch diameter, for the photographic work and exposures of eight minutes are made for the quick plates and of a minute and a half for the slow plates. the apparent inconsst- ency in the times of exposure being duo 10 the fact that the more sensitive plates are used just after the lunar sunrise or before the lunar sunset. when but little light Is obtanable from the crescent of the moon
 For photographic purposes the moon was divided into sixteen sections. and nve views were taken of each section since the lunar day is twenty nine and a half terrestrial days in length the frst view was taken at the lunar sun rise; the next, two days later accord ing to terrestrial time, the next at the lunar moon; the next, two days before the lunar sunset; and the last at the ctrra
 or the whole lunar sphere. so that alto gether the new atlas of the moon will contain between ninety and 100 plates arranged by sections on sheets for the more convenient use Of telescopic ob- servers, for whose benefit the atlas is largely intended Larger plates are being made and published at the Paris observatory, but the views taken there are confined to one of each section of the moon, instead of the five of each section which will be reproduced In Professor Pickering's new atlas. Since the Paris observatory is doing its par. ticular work to the entire satisfaction or the astronomers, Professor Pickering has practically confined his work to these serial views, which have been
 
 likeiy to be exceptionally useful in the l Identification of the moon'., various regions by reason of the fact that they show them systematically at different | stages. Such serial views should also | be of assistance in studying the dark l spots which appear within some of the ! craters, and which seem to wax and | wane with the lunar day and also to | change somewhat. in character during | period of years. 1t has been sug- l geSted that these spots are caused by | plants of some low order. possibly a | Kind of lichen, which blossom in the | sunlight and fade as sunset approaches.
 While the lunar geography is being studied at Jamaica, it appears that the [ local geography is not without it's pecu- | liar problems. The temporary station l. in a lonely region surrounded by forests with but one other house in sight. Az 1t sometimes happens that no ram falls during whole month the | water supply is serious consideration. Rain water i@ collected on cement plat forins called barbacues, which are built primarily for the drying of coffee and the pimento berriea which provide the ailspfce or commerce. The barbecue at the observatory is something like forty by eighty feet in size, slightly inclined 90 that the rainfall can be conducted to a cement tank for storage. It happens. however, that in the mountains the dew IS exceedingly heavy. and as the ob- serNatory buildings are roofed with galvanized iron. the Harvard party un- dertook by means of gutters to gather the nightly dew fall for drinking pur- pose;' Sometimes two or three gallons were collected in night, which the astronomers drank without apparently.