of the principal Jixed Stars which pass near the Zenith. 57 



In the year 1802, whilst Lieut. -colonel Mudge was em- 

 ployed in observing the zenith distances of the stars at the 

 Royal Observatory at Greenwich, with his zenith sector, 

 I computed for him the elements for the reduction of the 

 principal stars which pass near the zenith contained in 

 Dr. Bradley's Catalogue, and published in the Nautical 

 Almanac of the year 1777; and as they may, perhaps, be 

 useful to astronomers, or to such gentlemen as are desirous 

 to put into practice the verifications above alluded to, I 

 have arranged them in a Table, The first column contains 

 the Right Ascension, which is not computed with great ac- 

 curacy, being only intended to give the time of the star's 

 passing the meridian. The second column contains the 

 number for aberration in North Polar Distance ; the third 

 column its Maximum; the fourth column the Logarithm 

 af this Maximum ; and the fifth the Annua! Precession in 

 North Polar Distance computed to three places of figures. 

 The formulae by which the number and maximum of 

 aberration were computed are as follow: 

 Put P = the angle of position. 



Z = an arc. 



M= the maximum. 



N = the number for aberration in north polar 

 distance. 

 Log. s, P = log. c. Ai + log. s, obi. ecliptic + log. secant 



latitude. 

 Log. t, Z=z log. coscc latitude 4- locr. tang. P. 

 Log. J\d = 1-30103 + log. cosec Z + log. s, P; and 



The aberration becomes — M x c (O' long. <-,N.) 



Exuviple from the Table. 

 Suppose it was reqiiirid to find the aberration of /3 Dra- 

 conis on August lo, isoo. 



O" M August loth, noon 9'' 19"' 14* 



A\ /3 Diaconis , 17 25 58 



Time ot /3 Draconis passing the meridian nearly 8 6 44 



