GEORGIUM SIDUS. 



: : fecular variiition above foond : fccular varialjion required. 

 Before I'Sovhe fccular variation mull be taken with a lign 

 eontrary to that found in th,- table. With argument II. 

 take out the equation in Table VII., makirtg a proportion in 

 »his and in the following equations, for the intermediate 

 Bumbcrsof the arguments. With argument III., take out 

 theequation in Tal.ie VIII. With argument IV. take out 

 the equation in Table IX. With argument V. takeout tlie 

 rquation in Table X. With argument VI. take out the 

 equation in Table XI. With argument VII. take out the 

 equation in Table XII. With argument VIII. takeont the 

 equation in Table XIII. Tab^'Uic fum of all thefc equa- 

 tions, regard being had to the ligns of the firfl equation, and 

 of the fec'.ilar variation, the fi_:;ns of tlie others being pofitive ; 

 and from it fubtraft 7' 20", and you get the value of tliefe 

 eight equations ; and tills ap])lied with its proper iign to 

 the mean longitude already found gives the longitude of 

 the Georgian in his orbit. 



From the longitude thus found, fubtraci the longitude 

 of the node, and you have argument IX. 



With argument IX. enter Table XVII. and take out the 

 rcdudtion to the ecliptic, with its proper fign, making a 

 proportion for the minutes and feconds of the argument : and 

 this applied to the longitude of the Georgian in his orbit, 

 gives his true heliocentric longitude on the ecliptic, reckoned 

 from the mean equinox. 



With argument IX. enter Table XVI., and takeout th? 

 latitude, making a proportion for the minutes and fecond"; 

 of the argument, and you have the true heliocentric latitude 

 of the planet. 



With the mean anomaly ent<?r Table XIV., and take out 

 the radius vei£lor,'and correct it by tiie following Table XV, 

 and you have the true diitancc of the planet from the fuu, 

 that of the earth being unity. 



Example. — To find the heliocentric Latitude and Longitude of the Georgian, on Nov. 



Time at Greenwich. 



789, at 16'' 14', meau 



This is the true heliocentric longitude from the rai'im equi- 

 nox ; and if we want it from the true equinox, we mull ap- 

 ply theequation of the equinoxes. 



In t'-.'s operation the firft five lines are taken out imme- 

 diately from the tables, and the fums of all the columns give 

 tlie mean longitude of the aphelion, the node, and the ar- 

 guments for the given time. Argument I. is immediately 

 found according to the rule, the equation to which is thus 

 found. Theequation (Table VI.) for422''is — 3 26 59'.6, 

 anithe vari-itiouor 6o'is4'3i".l ; lience 6o': 54' I5"::4 31".! 

 : 4' 5". !, which (as the equation is decreafing) fubtrafled from 



— 3"i6'50 '•6gives— 3"22'54".5, theequation required. And 

 to find the fecular variation, that variation is -f- 7 '.44 for 

 422, and it deoreafes o". 16 for 60' ; hence 60': 54' 15 ' : : 

 o'. 16 : o'. 15, whicli taken from + 7"-44 leaves + 7 29", the 

 f cular variation correfponding to the given argument. Now 

 this feciiLir variation is reckoned from 1780, and from tlience 

 to November 26, 1789, there has elapfed 9 9 years ; hence, 

 100 : 9 9 : : 4- 7' 29 ' : + o".7 the fccular variation for 9 9 

 years. V\'ith argument II, 638, take the equation from 

 Table VII. Now the equation for 630 is 4' .7, and it changes 

 o".7 for 10; hence to ; 8 : : o",7 : o''.6, which asthcequa- 



4 tiica 



