DETERMINING THE LONGITUDE. 



247 



of the chronometer, is the interval in mean solar time, which, corrected by 

 the acceleration of sidereal on solar time, will be the interval in right ascension. 



Rule. 3d. Now, with the mean of all the mean right ascensions, and the 

 mean of all the declinations, compute from Mr. Fallows' Tables the corrections 

 for precession, aberration, and nutation, and which, applied to the said mean, 

 according to its sign, the sum, or difference, is a mean of the apparent right 

 ascension of the stars. 



Rule. 4tli. To this apparent right ascension, add the interval found by 

 Rule 2d, if the time of the moon's transit is greater than the mean of the times 

 of the star's transit, otherwise, subtract the interval, the sum, or difference, is 

 the right ascension of the moon's observed limb, from which that of her centre, 

 is deduced as before. 



The following example is cited in illustration of the proposed method. 



OBSERVATORY AT PROME IN AVA. 



13th November, 1825. 



• * w 



CO a 



— ITS 



Names and Cha- 

 racters of iSia}-s. 



Times of Transit jjer 

 Chronometer. 



31ean ARn. of 

 for 1825. 



Stars, 



Declination. 



a- Jl 



A O ^ 

 OD — • ^ 

 13 • . 



g : a 



36 Aquarius. 

 tA> ditto. 



1 h. ditto. 



2 h. ditto. 



3 h. ditto. 

 1 H ditto. 

 3 h. ditto. 



1 



7 



7: 



7 



7 



8 



8. 



3 : 44. 5 

 45: 51. 

 58 : 22. 

 58 : 32. 

 . 59 : 06. 2 

 09 : 02. 

 12 : 07. 



22: 1 : 15. 

 22 : 43 : 28. 

 22: 56 : 10. 

 22: 5G : 10. 



22 : 56 : 46. 



23 : 06 : 41. 

 23: 09 : 51. 



93 

 73 

 75 

 54 

 15 

 84 

 40 



12^ 

 8 

 8 

 8 

 8 



10 



10: 



: 25 



: 32 



: 40 



. 43 



55 



08 



40 



Sum. 



55 : 06 : 44. 7 



159: 50: 16. 



34 



68: 



03 





Mean, 



Moon's transit. .. 



Difference, 

 Rate, losing. 

 Acceleration, ti 



Interval in ARn. 



Correcti 



+ 

 an for I 



7: 52: 23: 51 



22: 50: 02. 

 • • • • •• 



33 



03. 81 



9° 



: 43 





8: 16: 13. 70 







00: 23: 50. 19 



+ .05 



+ : 3. 91 







00: 23: 54' 15 







'recession, &c. -{- 





, I 



Apparent right ascension, 



.. 22: 50: 06. 13 



