197

o n seeing the letter from Herrn Director Schmidt in X 1590 of the Astronomische Nachrichten, i n which he states that h e was surveying the heavens about Corona hetween

Athens time on the night of the 1zth of May, and must have seen the new variable 4tar TCoronae, bad it been then even as bright as the sth magnitude, by the distortion it would have produced i n the figure of the constellation, I w a s immediately struck by the fact that it was on that sqme night, May 12, that tbe s tar was Actually discovered by Mr. Birnzinglcarn, of Juam in Ireland. No printed record existing of the precise time of that gentleman's observation, Mr. Huggins kindly, a t my request, wrote to bim for the infor- niation, and the following are some extracts from bts aoswer:

Nr. 1597. 198

, , I was on the road some distance from here when I first s a w the s ta r , so I could not be sure of the time to a minute, but it was certainly between 11h30" and Ilh45" ON the night of the . . . . I t certainly was not later than 1lh45" P. m. local t ime. . . . I n size it wa's a t l e a s t equal to a c o r o n a e and decidedly more brilliant.. . . l o colour the s tar appeared n e a r l y white with a bluish tinge. 1 could see nothing of the orange of other observers.“

The conclusion from these facts combined appears to be that a t 8h Greenwich mean time the s tar was c e r t a i n l y fainter (and may have been much fainter) than the 5th mag- nitude, and that in about 4 hours afterwards it had increased to the 2nd, either suddenly or with great rapidity.

0 = - ON5 - 0,4472 x 0 = - 1,5 +0,0209 : 0 = + 5,8 +0,4167 : 0 = - 2 , o -0,2636 :

0 = - 2,5 -0,2102 :

Hier ist x = AL = A ( M O + r ) , y = $ n A r Y

z = A@ f

u = 1OOAp 9

V = , m = Ai

f0 ,3818 y +0,7301 2 - 8,4228 ZL +0,1113 v - 1 , 5 8 8 8 ~ +0,0449 : +0,0753 : + 0,6143 5 -1,1792 : +1,1361 I +0,7171 : +0,0454 : +11,8751 : +1,1256 : +0,8411 :

+0,1220: +0,4971 5 - 8,8140 : +0 ,5858 -- 1,4759 : +0,2502 : -0,2580 : - 7,9094 : -1 ,5152 : +0,5839 :

Gibt man dieeen Gleichungen gleiches Gewicht und liist dieselhen auf bekannte Art auf, so ergeben sicb die Verbesserungen :

A & = +1"25 A T = -18989 A Q = --0924 A p = -0,003247 Aa = -2969 A i = + O , l l ,

nnd die definitiven mittleren Elemente werden demaach : 1855 Jan. 5,O mittl. Berl. Zeit. M a = 223'54' 37"44 T = 193 21 49981 52 -= 22.0 42 55961

] m. Aeq. der Epoche.

i = 5 28 49987 @ = 4 45 43920

I O ~ U = 0~,4128449 : p = 299307392 p = 852"58795.

Substitnirt man die Verhesserungen tler Elemente i n die Bedingungsgleichungen , so erhalt man folgencle Fehler der Normalbrter :

R--R Aoc ro.9 d A d -- +0"3 -1"7 - 2 9 1 -092 + l , 6 -239 -193 - - I 9 2

- 1 9 4 + 0 , 6

+ 2 , 6 + 0 , 9 -076 -092 -098 -092

+092 - 1 9 1

+099 . -I93

Diese Darstellung der Beobachtungen ist sehr befriedigend und s o , dass man eioe bessere kaum bei Anwendung der speciellen Stiirungen erwarten kann, fur welche e s doch so einfach ist, die Glieder biiherer Ordnung vollstandig zu be- riicksichtigen. Die allgemeinen Pomonastiiwungen zeigen aber wieder, dass zu einer miiglichst sckarfen Darstellung der Beobachtungen auch die vom Quadrat der stiirenden Krafte abhabgenden Glieder nothwendig sinci.

A l t o n a , 1866 Juni1 . 0. Lesser.