THE 



PHILOSOPHICAL MAGAZINE 



AND 



ANNALS OF PHILOSOPHY. 



[NEW SERIES.] 



FEBR UAR Y 1831 



XIII. On the Construction of the Berlin Astronomical Ephe- 

 merisfor 1832. By Professor ENCKE.* 



IE comparison of the end of the last with the beginning 

 of the present volume, has not led to any corrections 

 worthy of being here mentioned, with the single exception 

 (the calculation of the si n's ephemeris having been finished 

 before a small alteration in the tables of correction was pub- 

 blished), that in this volume the sidereal time at the mean noon 

 is to be corrected by 0"*06. The two preceding volumes 

 gave it correctly. All other discrepancies lie within the limits 

 which are attainable by our tables as at present constructed. 



The form of the single parts has remained almost exactly 

 the same as before. The most important difference is one 

 which regards the small planets. The highly respected Dr. 

 Olbers, who continues with an unabated and wonderful vigour 

 of mind to devote his unwearied attention to that science which, 

 in so many of its parts, owes to him the most important im- 

 provements and enlargements, has kindly reminded me that, 

 for the more easy finding of the small planets, it would be of 

 consequence to know, besides their distances from the earth, 

 likewise their distances from the sun, in order to be able to 

 estimate the intensity of their light. I have accordingly added 

 a column containing those distances and instead of the three 

 columns ' Rising,' ' Culmination,' and ' Setting,' I have only 

 iven two, 'Time of Culmination,' and 'Semidiurnal Arc,' 

 rom which the others may be easily calculated. 



This subject is connected with a convenient estimation of 

 the light of the small planets at the respective times of their 

 opposition, for which I am indebted to Prof. Bessel, and, 



* From Encke's Epbemeris for the Year 1832. 

 N.S. Vol. 9. No. 50. Feb. 1831. M agreeably 



