REPORTS OF ASTRONOMICAL OBSERVATORIES. 72.') 



This redetermination ^vill result in tlio formation of a oataloirne of 

 1,210 stars, in which tlie positions will bo laid down with a ])n)bal>lr 

 error of about ^ second in each <'o-ordinate (the rectasccnsion i>robabl\ 

 more accurate). Most of the required observations were made l».v :\li'. 

 LiNDHAGEN, and the series is nearly (;omi)lete. The second series, 

 unfortunately, will have to be delayed, owinji" to necessary repairs of 

 the meridian circle, which exhibits traces of old aue. - - - 



From the results obtained by comparison in diiVercnt ])ositions, tlic 

 the probable error of a single declination detenaination is estimated as 

 0".5 to 0".G, which may be still reduced. 



Up to the present time the polar distances have been computed tem- 

 porarily from observatioiLS of the Nautical Almanac stars, with a])plica- 

 tionof the declination estimated in the fundamental cataloune for zone 

 observations in the IST. sky. Predominating, though not exclusive, use 

 having been made of extreme northern stars, it is ])resiunabh' that the 

 unknown inclination of the instrument has excited quile an intluence on 

 the results obtained. It is, however, evident from the coincidence of the 

 polar positions obtained in both situations of the objective and o<adar 

 that the inclination coefticient, which appears as multi))lied by the sine 

 of the zenith distance, cannot be very large. - - - 



The second series is intended to furnish a contribution to the knowl- 

 edge of the mean distances of the stars. ^Mention of this work has been 

 made in former reports, and an account of the progress made <huing 

 the past year is here presented. 



Of the stars previously mentioned as to be observed for parallax, two 

 have been omitted, namely, « Aurigiie, and '!/ Persei; the former on ac- 

 count of the diiierence of brilliancy between the principal star and a 

 comparison star, the latter on account of the ditierence of declination 

 of the comparison stars. These were substituted by a Corona", and 

 £ IJrsiB Majoris. In consequence of the brilliancy of the former the 

 observations will be rather diflicult an<l jirobably somewhat incorrect. 

 I propose, however, to continue them for some time yet, in order to test 

 whether the parallax may be conlined to satisfactory limits by a nudti- 

 plicatiou of the observations. The same is the case with o. Persei and 

 p Andromedre, notwithstanding their insufticient accuracy. 



In observing : Ursa Majoris use could bemadeof only one comparison 

 star; a second one, at lir'st designed to be included, i)ro\ing too indis- 

 tinct. The former, however, is in every respect satisfactory. This star 

 moves on the same parallel with the i)riiicii)al star and oOi seconds 

 ahead, and its magnitude, according to Argelander, is S.O, The consid- 

 erable brilliancy of this star admits of its observation even during un- 

 favorable state' of the atmosphere, and it has not l)een neglected not- 

 withstanding the sometimes very unsatislactory imi)ression obtaiiicd. 



It is therebv intended to arrive at another result in addition to the « e- 

 terminatiou of the parallax, namely, the collecting of material tor the 

 estimation of the relative accuracy which may be expected at the contact 

 of the cross-wire and right-ascension ditrerences during a lavorabh^ or 

 unfavorable condition of the atmospiiere. Although the results obtained, 

 until now, in reference thereto are not by any means conclusive, thej 

 are regarded as worth communicating. . , , ^ 



As the results of observations are computed, with but few exceptions, 

 from four transits, the probable error ±0M)17 is to be expec ed In 

 close conformity there is deduced from the 10 observations ot = Lrsa tx- 



'^^i^l^S^S'ot X ^^tory. Even if the probable 

 eri or of a rIsuK ofob^^^^^^^^^ were ± 0^020, 30 or 40 nights adequatel v 



