(6) 
Astronomy. — „The system of Sirius according to the latest obser- 
vations’. By Mr. H.J. Zwiers. (Communicated by Prof. H. G. 
VAN DE SANDE BAKHUYZEN). 
In N°. 3336 of the , Ast. Nachr.” I have deduced the system 
of elements of the companion of Sirius so as to have an example 
for the application of my new method of computing the orbits of 
double stars. I have found: 
Elements I. 
T = 1893.759 
fe = — 7.04486 (Period = 51.101 year) 
6 == Otol 
t= 44° 36'.0 
S= 37 3.6 (1900.0) 
A=a— =223 36.6 
The observations which served as a basis for this orbit, extend 
from 1862 till the spring of 1890, when the companion was seen 
for the last time at Lick-Observatory by Burnuam. For about six 
years it then disappeared in the rays of the principal star, till, 
towards the end of 1896, new measurements could be obtained again 
at Mount Hamilton. The absolute positions of Sirius, as observed 
in the meridian of Leyden, were reduced to the centre of gravity of 
the system by aid of the elements just given, combined prelimina- 
rily with the distance of the principal star to this centre, as found 
by Auwers. In pursuance of the same object I immediately after 
the reappearance of the component took the computation once more 
in hand. For the computation of the final values I thought it 
advisable however to await a few further oppositions. As soon 
as Messrs. KrEELER and ArrkEN of Lick-Observatory had kindly 
communicated to me by letter, in February and March of this year, 
the results of their measurements in the recent winter, I have deri- 
ved the final equations’). ‘The error of my ephemeris amounting 
1) An observation received iu the beginning of May from Prof. Husser arrived too 
late to be included in the computation. 
eee / 
