The Montgomery advertiser., 1902-04-13
TO STUDY THE wHIlIs OF
 THE sTRANGEST OF STARS.
Prof. Bailey of Harvard Astronom- ical Observatory Going to Arequipa, Peru, to Measure the Light of
 the Planet Eros.

Cambridge, Mass, April i2-one of the most interesting astronomical investfgations that has ever been made is being set on foot by the Astronomical Observatory of Harvard. from which Professor Solon I. Bailey starts auipa. Peru. to study the peculisrities of Eros which is. perhaps. the most remarkable or the asteroids minor planets yet discovered. While Eros comes nearer to the earth than any other celestial bodq. it's Igesence in the heavens was notd lses than nve years ago Since then it has been kept under constant sur I, was found that the planet was varlsoie-in other words, that its light was sometimes ususl characteristic was observed-one which no other known star has, in fact-nameiy, that It sometimes varies and sometimes does ass not. It is the cause of this irregular Variation that Professor Bailey will seek
 After the asteroids discovery its history was traced back by means of the great col, it's peculiar habits were discovered. All sorts of theories have been offered to account Tor most seriously considered being that it is either a double star or an elongateh. cigar, over end. as it were, so that first . broad side and then one end is turned toward the eartn' and 1t Is the latter explanation to which Fro. lessor E. C. Pickering the director of the Harvard Observatory, inclnes. This particular time has been chosen by the Harvard onserV. atory. for the stdy of the idiosyncsas'r5i 2. early in the summer of sos; that is to say, at that time it will he in line with both the
 
 restriaI observers, under more favorable con ditions for study. than 1t VIII be again TOT several years The Hsrvard & pnotos,apes n e sn1w s when it was in opposition in 1894. but that was before It's existence was known.
 The reason for carrying on the investigation et Areuufpa River than in Cambridge is that the orbit of Eros is tipped at such an angie to that of the earth that the asteroid VII pc practically invisible from here at the time of its opposition. barely rising above the horizon of these Northern iatitudes. The method of study. which will be used Is very im,er. sung; ,s light of the star will he made nearly every night during a period of six months LniS whl. of course, include the opposition; but 1t IS intended to begin the observations long be- fore that tifne--say. at the end -ot next Marcn when the Southern skies are clear of mist and haze and continue them into the Fall, until the stormy season comes on nssin; u Is hoped that the reason for the littIe pan, cts varying degrees of briiiancy may he found by examining the measurements of the vari- ous intcnsites of its light when it IS fin close The nneasurements will he mado with photometer-an ingenious telescopic d"H1ce' perfected by Professor pickering-'whieh brinss the light of any heavenly body that is t0 ne examined into direct comparison with light of known intensity. or. as the astronomers cal it. of a known magnitude. Much depends upon snr visual accuracy is an important factor Tn the comparison. and the whole operation requires. of course. great care. fine judgment and long
 Professor Bailey is probably better acquaint- ed with astronomical work DeloW tne eQudtot than any other living American astronomer. having spent many years at Areduipa HIS first visit was of two yeare' duration: and in the course of 1t he took part in the establish ment of the Harvard station which coop erating with the Observatory at Cambridge. has made possible the systematic and complete manning of celestial conditions from pole to pole day after day--a process that has been in some ways the most valuable single astro- nomical sccomplishment of the last quarter century. Tn his study of Eros he will be as sisted hy the members of the regular stan at Arequipa, which has recently been increased ny two yoIng men from the vicinity of Boston Mir Manson. a graduate of the Massachusetts Institute of Technology, who has had somc MT Nvetn