ASTRONOMICAL AND GEODETIC OBSERVATIONS. 



11 



The following four eclipses^ of Jupiter's first satellite were noted by tire pocket 

 chronometer : — 



1860. November 18 (19th A. M.). Disappearance 11'' 05™ 55'. A. Sonntag, observer. 



Jupiter much waving, time uncertain to 20^ 



1861. January 30 (31st A. M.). Disappearance IS"" 27° 46^ H. Q. Radcliff, observer. 



Note as above. 

 1861. February 6 (Tth A. M.). Disappearance 2" 21° 421 H. G. Radcliff, observer. 



Planet unsteady, time uncertain to 5'. 

 1861. February 8. Disappearance S*" 51™ 23'. H. G. Radcliflf, observer. 



Very slight snow falling, time uncertain to 20'. 



The same magnifying power of telescope was used in the above observations. 



We have no comparisons of chronometers on November 18, and as the pocket 

 chronometer was allowed to run down between October 31 and November 29, its 

 rate is determined from observations on October 17 and October 31, and its cor- 

 rection from observations on November 29. 



Observations for time, October Itth, 1860. 

 Double altitudes of o Lyras, with reflecting circle. 

 + 1' 40" +] 



Index 



Pocket clironometer 



10" 00™ 26= 



1 26 



, 2 20 



3 56 



5 22 



6 45 



7 48 

 9 21 



10 32 

 10 11 37 



:_2°, B = 29'".390 at 31° 



US' tr ii' IS" vi sSi «»'-«»» + '' '»■ 



Pocket chronometer 



10" 12™ 26' 



13 19 



14 18 



15 30 



16 43 



17 45 



18 56 



20 13 



21 02 



22 08 



2* 



83° 40 

 34 



■{ 



M 



1^ 

 11 



q 







82 54 

 49 



Index 



f +1' 40" +1' 50" +1' 00" 

 '1+1 40 +1 40 +1 10 



Corr'n + 1' 30" 



These observations will be combined two by two. 



Refraction r for first observations — 1' 10". 3, for last — 1' 12". 9 



Star's declination s = + 38° 39' 34". 9, right ascension 18" 32™ 13'. 5 



mi, 1 1 , • r 1 r j siii 7i — Sin d) sin S 

 ihe hour angle t is lound from cos t^ ^ 



cos <|) COS 



'■ Three other observations were found to be occultations of the satellite, not eclipses ; they are of 

 no value for our purpose. 



