152 



KNOWLEDGE 



[July, 1902. 



ASTRONOMY WITHOUT A TELESCOPE. 



By E. Walter Maunder, f.b.a.b. 



XV.— NEW STARS. 



Thk ap])earance of a "new star" has, in all ages, l)eeii 

 felt, to be an impressive occurrence. The constellation 

 grouping's are so permanent in their eharactcr, that to .see 

 of a sudden some old familiar pattern amongst the stars 

 clianged in its featun-s by the sudden appearance of a 

 new member, a star like the other stars and not a planet, 

 for its place undergoes no change — is so at variance with 

 our ordinary experience, that it is no wonder that our 

 ft)refathers regarded such an event as partaking of the 

 supernatural. In the times before the telescope — indeed 

 we might go further and say in the. times before the 

 spectroscope — such an event brought no information with 

 it. It was impressive, it excited curiosity, but it convoyed 

 scarcely any lesson. The spectroscopic examination of 

 " new stars," on the other hand, has been extraordinarily 

 fruitful, though we are very far as yet from being able to 

 fathom the exact meaning of the facts which we have 

 observed. One thing is clear, namely, that bodies ap- 

 pearing so suddenly as " new stars " have always done, 

 and fading away again so quickly, must differ entirely 

 from the great host of permanent stars. And yet we 

 cannot but feel that the changes through which a "new 

 star " may j)ass in a few weeks, and the order in which 

 those changes succeed each other, may throw much light 

 upon the changes which have marked in the past, or will 

 mark in the future, the life-history of the more stable 

 memliers of the heavenly host. 



It is this thought which makes the watch for " new 

 stars " of such importance. They offer to us a key, which, 

 however imperfect, is the only one which we can hope to 

 find to unlock the secrets of stellar evolution. And that 

 the "new star" may give us the fullest information 

 within its power, it is essential that it be subjected to the 

 scrutiny of the spectroscope whilst its light is still on the 

 increase. The importance therefore of a stringent vratch 

 on the heavens does not lie at all in the I'dat which will 

 justly attach to the observer who is fortunate enough to be 

 the first to detect a stellar outburst, but in the supreme 

 importance that not one of the few short hours during 

 which the star's light is on the upgrade may be un- 

 necessarily wasted. 



Such watching is not for the casual star-gazer, nor for 

 the dilettante who has never taken the trouble to master 

 the star-groupings and the coming and going of the 

 planets. The planets especially are sad foes to such un- 

 qualified aspirants ; and just as the " Crab " Nebula, 

 Praesei)e, and even the Pleiades, have sent many eager 

 comet-hunters in hot haste to claim a comet medal, so 

 Venus, Mars and Jupiter have inspired hundreds of 

 letters to observatories or to newspapers to draw attention 

 to "the wonderful new star." One of the most amusing 

 instances of the kind was when the discoverer of the 

 pseudo-planet Vulcan announced to the Paris Academic 

 des Sciences his discovery of " a strange object in Leo," 

 which proved to be no other than the planet Saturn. 



The first duty, therefore, of the watcher for " new stars," 

 is to work slowly, steadily, and systematically through the 

 constellations till he has made himself thoroughly ac- 

 quainted with the appearance, brightness, and position of 

 their every member. When he has done this, then night 

 after night it will be his task, whenever the skies are clear 

 enough, to carefully scrutinise all the stars within his 

 view. The labour will be great, but it must be borne in 

 mind that such acquaintance with the heavens and such 

 regular scrutiny of them are necessary for all the varied 



branches of " Astronomy without a Telescope," S'j that Ihf 

 watch for " new gtiws " may well be inciilcntal only to 

 other lines of worjf. To Ix- the discoverer of a " new star" 

 renders an observer rightly famous, but as the experience 

 of the past fifty or sixty years shows that we cannot hope 

 to record a discovery of the kind more frequently than 

 once in nine years on the average, it is clear that it ought 

 to be made subsidiary to some more fruitful line of 

 research. The systematic t.-ye study of the Jlilky Way is 

 particularly a form of astronomy which might be combined 

 with it ; since it is on the Milky Way, or on its branches, 

 that all the Novie have been found, as the accompanying 

 diagram will show. 



The most famous of all " new stars " is, of course, the 

 one whidi appeared in the constellation Cassiopeia in 

 November, 1572, and which is always associated with the 

 name of Tycho Brahe, since, though he was not actually 

 the first to discover it, he has left us the fullest and most 

 systematic observations of it. It was lost to sight in 

 March, 1574, after having been visible for seventeen 

 months. Thirty years later another " new star " appeared, 

 only less famous than the Nova of Cassiopeia. This one 

 was also observed for seventeen months, and is always 

 associated with the name of Kejiler, though its actual 

 discoverer was not Kej^ler himself, but one of his ]>ujals, 

 John Bronowski. Its position was in the right foot of 

 OiJhiuchus. 



No such brilliant Novx as these have been seen in more 

 recent times, since both stars were reckoned, when first 

 seen, to be brighter than Ju2>iter ; indeed the star of 1572 

 ranked as equal to Venus when at her greatest brilliancy. 

 The first of those noted in modern times was, like that of 

 1604, discovered in the constellation Ophiuchus. It was 

 detected by Mr. Hind on April 28th, 1848, and was then 

 increasing in brightness. Four days later it attained its 

 maximum, which only ranked it of the fifth magnitude. 

 The second star of the list was discovered in the globular 

 cluster 80 Messier, which lies between Alpha and Beta 

 Scorpii. The third was detected by Mr. Birmingham at 

 Tuam on May 12th, 1866, when it was recorded as of the 

 second magnitude. It may be doubted, however, whether 

 this star is quite of the same order as the others. It had 

 been observed several years previously as of magnitude 

 9^, and it still remains visible, being now classed as a 

 variable under the name T Coronas. Still its outburst 

 must have been very sudden, for Dr. Julius Schmidt, 

 whose acquaintance with the heavens was of the very 

 closest, declared that about two and a half hours previous 

 to Mr. Birmingham's discovery, he had the constellation 

 of the Northern Crown under his observation, but had 

 noted nothing unusual. The next discovery was to fall to 

 his own lot. On November 24th, 1876, he found a third 

 magnitude star had appeared in the constellation Cygnus. 

 This star rapidly faded away, and was only of the fifth 

 magnitude on November 30th. Its spectroscopic history 

 was of intense interest, for, by September, 1877, the light 

 coming from the star was almost entirelj' monochromatic, 

 and corresponded with that which would be given by a 

 planetary nebula. 



The next " new star," discovered independently by a 

 considerable number of observers in August, 1885, was 

 actually involved in a nebula, the great nebula of 

 Andromeda, and was close to the nucleus. This was 

 wlK.lly a telescopic NoiHi, and since that time several other 

 telescopic Novte have been discovered by means of the 

 photograjthic charts which have been made at the Harvard 

 College Observatory, or at its southern annexe at Arequipa, 

 Peru. But two Novx have been detected besides these, 

 both of which were naked-eye objects, and the history of 

 their discovery is La the highest degree encouraging and 



