EQUATORIAL INSTRUMENT. 



EQUATORIAL INSTRUMENT. 



Applying these corrections to the observations of the comet, we 

 have 



IL. m. .. 



Time by dock 17 27 ll'fi Inrtrumenti. X.P.D. + 62 11 1 

 Inrtl. hour angle 2 SO S8'l Correction + 2 51 



Jnstl. R.A. comet 

 Correction . . 



143633-4 

 -r 1 16-2 



N.P.D. 



+ 02 13 62 



True R.A. comet 148740-6 



The star of comparison in, in this case, much too distant both in 

 R.A. and N.P.D. ; and the index error ought to be determined by stars 

 above and below the comet, and preceding and succeeding it. Also, 

 after the observations have been made in one position of the inurn- 

 ment, it ought to be turned half round and the observations repeated ; 

 but the mode of ascertaining and applying the corrections is the game, 

 and needs no further explanation. 



The acconi]>anying figure represents \heportable unirertal equatorial 

 as constructed by Troiighton (a drawing and description of a similar 

 instrument, under the title of Payrer's Equatorial will be found in 



The Equatorial. 



