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I. 0 ?z t/;e Method of determining the (places of the 
Planets hy obferVmg their near Appulfes to the 
Fixed Stars. By Edmund Halley, LL. D. 
Aftron. Peg. & peg . Soc. Soc. 
O F all the Cadeftial Obfervations that have hither- 
to been made, none are fo capable of perfed Ex- 
a&nefs, as the near Appulfes of the Moon and Planets 
to the Fixed Stars, fuch as lately we had of Jupiter to 
two fmall Stars in Gemini , and of Mars to the Fore- 
head of the Scorpion ^ for though the Places of the Stars 
have not as yet attained an ultimate Precifion, yet thefe 
Sorts of Obfervations are ever good, and the Places 
of the Planets are thereby afcertain’d, in Proportion to 
the Corrednefs of the Catalogues that may hereafter be 
made : But the ordinary Number of the Stars, with 
which the Planets may be thus compared, being fmall, 
the Opportunities of obferving are confequently rare : 
Whence appears the great Ufe of a full Catalogue of 
Telefcopical Stars, at lead within the Limits of the 
^odiack , visss. that thereby thefe Opportunities may be 
more frequent : And wherever fuch Obfervations have 
formerly been made to thefe fmall Stars, we may be 
enabled to find them out, and by determining their 
Places, to be certain of the Places of the Planets alfo : 
Ol which I have given a notable Inftance in finding the 
Place of the great Comet of 1680, in its fir ft Appear- 
ance, even before it had a Tail vifible to the naked 
G S Eye, 
