250 



KNOWLEDGE 



[NOVEMBEB, 1901. 



now shown in our star atlases, are preserved for us in 

 the description of Aratus. Of the first he says: — 

 " Htr garlanded head. — her shoulder.s bare admire — 

 Her diamond sandalled feet, — her rich attire; 

 She still in heaven her captive form retains. 

 And on her wrists still hang the galling chairs." 

 His description of the constellation of Pegasus is one 

 of tlie fullest and most detailed of anv. There is no 

 need, however, to cjuote the whole, but he calls attention 

 to the circumstance that the star, now known as Alpha 

 Andromedae. the upper left hand star of the square, is 

 common to the two constellations. Its name, Alpheratz, 

 " the Horse, " perpetuates the same tradition — 

 " Close and above her head the wondrous steed. 

 With hoof and wing exerts a double speed. 

 So close they meet, one brilliant .star they share ; 

 Its body it adorns, and decks her hair. 

 His side and shoulder with three others graced 

 As if by art at e/jual distance placed." 

 That is to say. these three with the star common to 

 the two figiues make up the square. 



Of Perseus, Aratus says, after refeiring to 

 Andromeda ; — 



" Her anxious eyes 

 Tileam bright with hope ; beneath her Perseus flies, 

 Her brave deliverer — mighty son of .Jove — 

 His giant strides the blue vault climb and move 

 A cloud of dust in heaven. His falchion bare 

 Reaches his honoured step-dame's golden chair." 



The " cloud of dust " alluded to is the Milky Way. 

 on an arm of which. Mirfak, the chief star of the con- 

 stellation, stands. This '' dust round Mufak supplies 

 perhaps the finest field for an opera-glass in the entire 

 sky; the whole region being full of winding streams of 

 stars of the most attractive form. Moving upward from 

 Alpha towards Cassiopeia, we pass through Gamma and 

 Eta Persei. From Eta Persei. half-wav to Delta 



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Die Midnight Sky for Loudon, 1901, Xuvend)er (i. 



Cassiopeia, lies a cloudy object, the great cluster of 

 Perseus, one of the finest sights the heavens have to 

 present. Then, again, in the centre of the triangle 

 formed by Gamma Persei, Gamma Andromedae and 

 Algol, lies the comet-like cluster, 34 Messier. Ci'ossing 

 over to the constellation of Andromeda, Gamma Andro- 

 medae marks the neighbourhood of the shower of 



meteors associated with Biela's comet, and now en- 

 countering our earth about November 23. Passing on 

 to Beta Andromedae, we find that the starting point of 

 a line of three stars pointing upwards towards 

 Cassiopeia. The next of these stars to Beta is Mu, the 

 third Nu, close to which, towards the east, lies the 

 great nebula of Andromeda, 32 Messier — after the great 

 nebula in Orion the finest example of that order in 

 our skies. 



The entire region of Perseus repays examination with 

 the opera^glass. and of Andromeda the regions nearest 

 the Milky Way. Pegasus is much less interesting, but 

 possesses a naked-eye double in Pi, the stax in the 

 horse's hoof. 



Two small constellations in this region of the sky 

 may receive a passing notice. Immediately below the 

 Dolphin and close by the head of Pegasus, is the little 

 group Equuleus, the " Forepart of a Horse." It is 

 placed in the sky in such a manner as to suggest that 

 Pegasus is not rushing through heaven alone, but is in 

 close company with a yoke fellow, whose head, indeed. 

 is just seen, but whose body is Itidden from tis by that 

 of Pegasus. The constellation is not mentioned by 

 Aratus. but it is stated that Hipparchus formed it from 

 stars formerly belonging to the Dolphin. It is 

 described as we now have it in the catalogue of Ptolemy. 



The other group is Lacerta. the Lizard, a few faint 

 stars gathered together bj- Hevelius to fomi a constella- 

 tion fitted in bet-ween Cepheus, Cygnus, Pegasus and 

 Andromeda. Except that it marks the radiant point 

 of the Lacertids, a meteor shower, active in August and 

 September, there is nothing to distinguish the group. 

 Apparently at one time the fore leg of Pegasus crossed 

 this region, since Pi Cygui. which lies beyond it from 

 Pegasus, bears the name Azelfafage, the " hoof of the 

 horse. ' 



NOVA PERSEI. 



By E. M. Antoniadi. f.i;..\.s. 



O.N a photograph taken at Juvisy by the writer on 

 August 19 last, with M. Flammarion's portrait lens of 

 6i in. aperture and 27 h in. focal length, the image of 

 the Xora appeared quite different from that of the 

 stars. The exposure was 30 minutes only, so that the 

 imat;e measured only alioiit ^hi 'tich in diameter. Its 

 pe(!uliarity lay in the fact that whereas ordinary stars 

 impress the plate as slightly '' nebulous. " radiating discs, 

 the Xoirr showed a strong, sharply defined '" penumbra," 

 lound a small, dark nucleus. The diameter of this 

 " aureola was 2'. On the whole, the appearance was 

 not unlike that of a normal, quiescent, sunspot. 



The following night, August 20-21, proved admirably 

 transparent, and a plate was tried from 23h. 26m. to 

 3h. 6m. G. M. T., with an efiective exposiu'e of some 

 3 hours and 20 minutes. On this negative, the 2' 

 " aureola " is quite black. But the Xora is sun-ounded 

 by another one of 6'. Enlarged views of these images 

 wdl be foiuid in the annexed figure, carefully drawn bv 

 the wTiter from the originals, while the Plate gives 

 photographic enlargements of them. 



Notwithstanding the fact that a few weeks before 

 these photographs were taken, the spectrum of the Xora 

 had drifted into that of a nebula, it was obvious that 

 the " nebulosity '' round the image of the star could not 

 be real. Its shai^ boundaries, which repeated all the 

 optical defects of the object glass, precluded the possi- 

 bility of such an interpretation. This view was, there- 

 fore, communicated to Mr. Crommeliu, of the Royal 



