101 RECORD OF SCIENCE FOR 1886. 



STAR CATALOGUES, ETC. 



SchonfeWs Southern Durchmusterung (1855.0). — This catalogue con- 

 taius tlie approximate positions of 133,659 stars between 2° and 23° of 

 south declination — that is, all stars between those limits down to the 

 tenth magnitude. It carries Argelander's " sweeps " as far south as the 

 latitude of Bonn will permit, and is on essentially the same plan as the 

 ISTorthern Durchmusterung. In the details of the work, however, several 

 improvements have been made: Instead of Argelander's little 3-inch 

 glass, magnifying nine times, Dr. Schonfeld used a telescope by Schroder 

 of 6^ inches aperture with a magnifying power of tweutj'-six, and with 

 the field slightly illuminated. The width of the zones was H°, instead 

 of 2°, the width of the older zones. This involved more hours of obser- 

 vation, but the accuracy of the work and the certainty of catching faint 

 stars were increased, since the observer was not obliged to take in every- 

 thing up to the limit of visibility. A further advantage which the 

 Southeru Durchmusterung possesses IS thatDr. Schonfeld has himself 

 made all of the observations and revisions, so that the work is more 

 homogeneous than the Northern Durchmusterung. The observations 

 were begun, after some preliminaiy experiments, on the Gth of June, 

 1876; by the 28th of March, 1881, the zones had all been observed for 

 the second time. There are, including sixteen zones subsequently re- 

 observed, 363,922 observation s, all reduced to 1855.0. The revision, 

 also by Dr. Schonfeld and with the same instrument, embraced 5,700 

 positions, and was finished between April, 1881, and March, 1884. 



From the summary of the stars in each square degree it appears that 

 the Southern Durchmusterung is richer in st.ars than the Northern, in 

 the ratio of 1.21 to 1. The fainter stars (under the ninth magnitude) 

 are much more thoroughly observed than before, the limit being the 

 tenth magnitude instead of 9.5, that adopted by Argelander. The i)rob- 

 able error of a single estimation of magnitude for stars of the 9.5 mag- 

 nitude is only 0.11 magnitude, and for the seventh magnitude, 0.26 

 magnitude. The charts accompanying the catalogue contain an hour 

 each in right ascension. 



The Argentine General Catalogue. — The observations from which this 

 catalogue was formed were made with the meridian circle of the Cor- 

 doba Observatory during the years 1872-'80. During these years the 

 zone observations were the chief object of attention, and the catalogue 

 contains the places of 32,448 stars whose positions were more elabo- 

 rately determined during the progress of that great work, and consti- 

 tutes an addition to our knowledge of southern stellar positions of ])er- 

 haps not less importance than the Cordoba Zone Catalogue. The Gen- 

 eral Catalogue gives the positions for the epoch 1875.0 of most of the 

 southern stars brighter than magnitude 8i, the deficiencies in this re- 

 spect being chiefly found north of the parallel of 23°, at which the zone 

 begins. These omissions will be of comparatively small importance, 



