Mav, 1901.] 



KNOWLEDGE. 



io< 



ai-e none of them of the first rank, and are not disposed 

 in any easily followed figures. Its principal st.ar. Alpha, 

 Ras-al-Hague, " the head of the serpent charmer," lies 

 midway between Vega and Antares; as the old rhyme 

 has it : — 



_■' Through Ras !>1 Ila^ue, Vpga's beams directs the enquiring eye 

 Where Scorpio's heart, Antares, decks the southern summer skv." 



Ophiuchus is engaged on a double labour. Aratus 

 describes him thus : — 



" His feet 9t:imp Scorpio down, enormous beast. 

 Crushing the monstiTS eve and plaited breajt. 

 AVith outstretched arms he holds the Serpent's coils; 

 His limbs it folds within its scalv toils; 

 With his right hand, its writhinj tail, be grasps ; 

 Ita swelling neck, his left securely clasps. 

 The reptile reais its crested head on high 

 Reaching the seven-starred Crown in northern sky." 



The head of the serpent is marked out by five stars in 

 the shape of a capital X, immediately below the semi- 



. ^ ..iyiS'-^ 



CASSIOPEiX 



/<^ . CYCJJllS-,^ ~'» e MINOR 



CAI^aOPAROUS 



^c»' 



>^+ a^^f^ 





*■ '#•..•.••.*?> 





« UKCi 



HERCULES . 



v^^ 



> cotom* 



• VIROC • • 





e» • 





• LUPUS 



The Midnight Sky for London. 1901, Hay 6 



circle of the Northern Crown. The five stars are Beta 

 and Gamma at the feet of the X, Kappa in the centre, 

 and Iota and Rho at the top. The small stars cluster- 

 ing near this X of the Serpent s head make an interest- 

 ing field to the opera-glass, Isut the tip of the tail, marked 

 by the star Theta, is more interesting still. Theta may 

 be found by drawing a line from Beta Herculis through 

 Alpha Ophiuchi, and it is situated in a striking channel 

 in the Milky Way, one side branch of which comes to 

 an end Just on the borders of Ophiuchus. 



THE NEW STAR IN PERSEUS. 



The following is an abridgement of Harvard College 

 Observatory Circular Xo. 56: — The cable message an- 

 nouncing the discovery of a new star in the constellation 

 Perseus, by the Rev. T. D. Anderson, was received at 

 the Observatory early in the evening of February 22, 

 1901. Owing to clouds, the new star was only 

 occasionally visible, and twice it was necessary to cover 



the instruments on account of falling snow. During the 

 int<nvals, however, various observations were made, 

 which have a value owing to their early date. 



Meanwhile, an examination was being made, by Mrs. 

 Fleming, of the photographs of the region obtained here 

 earlier in the month, with the various instruments. The 

 photograph taken with the Cooke lens on February 19 

 had an exposure of 66m., beginning at llh. 18m. Green- 

 wich mean time. While this photograph showed not 

 only the faintest stars contained in the Durchniustc- 

 rung, but also stars as faint as the eleventh magnitude, 

 no trace of the nova was seen. A photograph taken 

 with the 21 inch Bruce telescope on October 18, 1894, 

 with an exposure of 15m., shows no trace of this object, 

 although stars as faint as the magnitude 12.5 are well 

 seen. 



The general appearance of the photographic spectrum 

 (on February 22) resembled that of the Orion type and 

 was very unlike that of the other new stars, in which the 

 bright lines are the most conspicuous feature. This star 

 had a long continuous spectrum traversed by 33 dark 

 lines. On careful examination the lines 3970, 4102, 

 4341, 4481, and 4862 were seen to be bright on the edge 

 of greater wave length. The line 46G5 was bright on 

 the edge of shorter wave length, or there was a bright 

 line whose approximate wave length was 4660. On 

 February 23, the clouds were so dense that few obser- 

 vations could be made. The spectrum was photographed 

 faintly and showed no marked change except that the 

 line K, which was absent on the previous evening, was 

 present and nearly as intense as Ha. On February 24 

 the spectrum showed a remarkable change. It was 

 traversed by numerous bright and dark bands, and 

 closely resembled that of Nova Aurigae. The principal 

 lines were dark with accompanying bright lines of some- 

 what greater wave length. The bright lines accompany- 

 ing K and He were reversed, and traversed by narrow 

 well defined dark lines. These last lines, and. one of 

 somewhat shorter wave length than H/3, are the only 

 sharply defined lines in the spectrum, all of the others 

 being broad and hazy, and difiicult to measure with 

 accuracy. On February 25 the spectrum differed .slii^litly 

 from that of February 24. The lines H8, Hy, and H^ 

 were also reversed and replaced by one or more narrow 

 dark lines. On Febniary 26 the changes in the spectrum 

 were slight. 



Observations of the position of the nova were made 

 by Mr. J. A. Dunne, with the 8 inch meridian circle, 

 on February 23, 24, and 25, with the result for 1900.0, 

 R.A. 3h. 24m. 2402s., Dec. -j- 43° 33' 424". 



It therefore appears that dn or before February 19. 

 1901, the star was invisible, or at least fainter than the 

 eleventh magnitude. On Februaiy 21, its magnitude 

 was 2.7, according to Mr. Anderson. On February 22, 

 its magnitude was 0.5, perhaps becoming a little brighter 

 on February 23, and then diminishing, so that on Feb- 

 ruary 25 its magnitude was 1.1. Its spectrum on Feb- 

 ruary 22 and 23 was of the Orion type, nearly con- 

 tinuous, traversed by narrow dark linos. During the 

 next 24 hours an extraordinary change took place, so that 

 on February 24 the spectrum resembled that of the other 

 novje. It was traversed by bright and dark bands, and 

 the principal dark lines had accompanying bright lines 

 of slightly greater wave length. 



During the last fourteen years, and since the general 

 application of photography to astronomy, eight new 

 stars are known to have appeared : Nova Persei. in 1887 ; 

 Nova Aurigae, in 1892, Nova Normae, in 1803; Nova 



