The Bridgeport evening farmer., 1917-11-22
By Dr. c. s. Brainfn of the Columbia
 University Observatory Staff.


 | entirety throughout North America. 1 Such an eclipse, while not of the same | scientific value as the total eclipse | of the Sun, is nevertheless of great | interest to the amateur astronomer in particular. It serves to impress l upon his mind the wonderful achieve ments of modern astronomy in learn | ing and reducing to mathematics the | laws of the motions of the solar sys- | tenn and emphasizes to him the re- i markab1e power of prophecy which | science possesses. IL serves a new confirmation of the fact that the laws of nature still hold.
 Of course, the professional astron- | omers are somewhat blase on this l subject, and mere eclipse of the | Moon evokes very little enthusiasm | in most of them. However, there are some, probably many, who take | care not to miss this phenomenon, in spite of the fact that they hardly ex- i pect to learn anything new from the | observation. It is a miIlion-to-one chance that the calculations of the astronomical computor are correct to | the second. But there Is something | so inspiring, so majestic in the un- | wavering march of the shadow that one gets here as in few other naked | eye events in tke heavens a real feel ing of the truly awful movement of the cosrnic bodies through space. f Circumstances of the Eclipse. The eclipse will take place on the night of December 22-23. We will give the exact time data. in Eastern standard time Washington. New York, etc.), from which the correc- tions for the other standard time belts of the United States and Canada can easily be made. At 1:54 in the morn ing the Moon enters the so-called pe- numbra, the partial or outer shadow, which will produce a hardly noticea- ble darkening of the Moons disk. At five minutes past o'clock the Moon enters tn eumbra or complete shad- ow thrown by the Earth, and this is really the beginning of the visible eclipse, for from then on the shad- ow creeps rapidly over the surface of the Moon, eating out more and more of the bright surface. until the total eclipse commences at 4:38. The middle of the total eclipse is at 4:46 and it's end at 4:55; the totaHty has thus lasted about IT minutes.
 The first bright patch now appears, and the shadow retreats as rapidly as it came on, until finally. at 6:27, the umbra has entirely left the Moon. The latter passes out of the penumbra finally at 7:29 The most interest ing part to watch. of course, Is from just before the entrance into the dark umbra until the end of tn etotality and the re-appearance of the bright surface. There Is no use in sitting out the whole performance as listed above.
 To change the above time data to other standard times than the Eastern, 1t is necessary to subtract one hour for those who live in the Central belt, to subtract two hours for those in the Rocky Mountain belt and three Tor those in the most westerly or Pacific time, belt. Observers in the easterly tip of North America, which is in the Inter-colonia1 or Atlantic stan dard time belt, add one hour to the above times. As an example, the middle of the eclipse will be at 5:46t by Atlantic time, 4:46 by Eastern time, 3:46 by Central time, PAS by Rocky Mountain time, and finally, 1:46 by Pacific time. The phenome- non is visible over an entire hemis- phere at practically the same instant. for every person who has the Moon above his horizon will be able to see it.
 Lunar and Solar Eclipses.
 The lay reader win probably be very much surprised to learn that the lunar eclipse is really a rarer phe- nomenon than the less often observ- ed solar. This is true in the actual number of occurrences, but the in- trinsic difference between the two phenomena makes the solar apparent ly the rarer. The difference lies in the fact that, as stated above, a lunar eclipse, when 1t happens, is visible to the inhabitants of an entire hemis- phere, whereas solar eclipse is visi- ~b1e only to a rather limited area.
 The Sun is the source of it's own light, but the Moon shines by reflect ed glory only. At the time of Iu- mar eclipse the Earth interposes it's bulk between the Sun and the Moon, thus cutting off the Moons light en- tirely, and any person situated in that hemisphere where it is night at that particular instant will have the eclipse. The Moons surface is en- tirely dark, except for the very weak "earthshine,' which is sunlight re- fiected from the Earth's surface to the Moon and back again to us.
 In the case of the solar eclipse the Moon gets in between us and the Sun, and for those whose view of the Sun Is intercepted there is an eclipse. ie, for those who are in the shad- ow path of the Moon. Because of the relative distances of the Sun, Moon and Earth, this shadow of the Moon never covers very large area of Earth, particularly the darker part of the shadow, Sometimes, when the Moon is relatively far away, the tip of the umbra or full shadow does not quite reach the Earth, but the pe- numbra or partial shadow does. In this case we have what is called an annular or ring-shaped eclipse of the Sun. There will be places on the Earth where the Sun will be seen