BARNARD— SOME PECULIARITIES OF THE NOV^. 101 



declining phase was brighter than that of any other modern nova, 

 for it was originally a brighter star than any of them with the excep- 

 tion of Nova Coronse of 1866, whose range of brightness was not 

 nearly so great. Before the outburst Nova Aquilse was a compara- 

 tively bright star of 10.5 magnitude. Nearly all of the other novae 

 have started either from a very faint condition or from one of entire 

 invisibility. It is easy to show that if some of the other novae had 

 been as bright as Nova Aquilse in the beginning they would have 

 much outranked it when at their maximum brightness. This was 

 specially so in the case of Nova Persei, which would have been a 

 brighter star than Nova Aquilae, because its entire increase of bright- 

 ness was much the greater of the two. This has given some hope 

 that the great nova of 1572 (Tycho's star), which was by far the 

 brightest nova on record, may have been a considerable star when the 

 outburst occurred, and that it may now be visible as such. But we 

 have no means of identifying it. The uncertainty of Tycho's position 

 of it and the rich region of the Milky Way in which it exists makes 

 it quite impossible to identify it among the many stars in its imme- 

 diate region. Should, however, a small variable star be found suffi- 

 ciently near to its assumed place, it would add much to the supposition 

 that the great nova had been found. It would be interesting to re- 

 cover this star now, for it might be bright enough for spectroscopic 

 study. The great lapse of time since it appeared in 1572 might give 

 results of much value in the history of these stars. 



There seems to be good claim that P Cygni of 1600 was a real 

 nova. It is therefore the oldest nova that we can certainly identify. 

 If we follow the information we already have of the novoe, it would 

 seem that this star, if a true nova, was probably visible to the naked 

 eye previous to its outburst. 



The next oldest, and one where there is no doubt of identity, is 

 Hind's Nova Ophiuchi of 1848. Though this star was not bright 

 enough to attract very wide attention, a few astronomers observed it 

 carefully. Bond, at the Harvard College Observatory, measured its 

 position with respect to a small star near it. From this it is identified 

 with certainty. While bright enough, it was also observed at Bonn 

 and is BD — 12° 4633. Recent observations show that the star is- 

 probably variable. 



