C 127 ] 



VII. Obfervatlons of a new variable Star, In a Letter from 

 Edward Pigott, Efq. to Sir H. C. Englefield, Bart, F, jR. ^S". 

 and A, S, 



Read December 23, 1784, 



DEAR SIR, 



FOR fome years pafl I have been employed in verifying 

 all the ftars fufpedled to be variable, in order that here« 

 after we may know with certainty what to depend upon. This 

 undertaking, which is nearly completed, has already proved 

 of ufe in deteding many miftakes, and producing fome difco- 

 veries ; among which, the following is one of the mofi: im- 

 portant. September 10, 1784, I firft perceived a change in 

 the brightnefs of the flar 17 Antinoi, and by a feries of obfer- 

 vations made ever iince, I find it fubje6: to a variation very 

 iimilar to that of Algol, though not exadly the fame in any 

 one particular. 



7} Antinoi, when brlghteft, is of the thii'd or fourth magni- 

 tude, being between ^ and j9 Aquila^ ; and at its leaft bright- 

 nefs of the fourth or fifth magnitude, it then being between 

 that of i Antinoi and ^ Aquilae; therefore, its greatefl varia- 

 tion in brightnefs may be called about one magnitude ; and the 

 changes it undergoes, though probably not nicely afcertained 

 from fo few obfervations, are nearly thefe : 



