Pope. — On the Southern Stars and other Celestial Objects. 165 



Aet. XII. — Notes on the Southern Stars and other Celestial Objects. 

 ' By J. H. Pope. 

 [Read before the Otago Institute, l^th October, 1879.] 

 This paper embodies the results of observations made during tbe last eight 

 years. While most of the work is original, yet, when the object described 

 is important, and an account of my observations could not be satisfactorily 

 given without reference to the work done by previous observers, their facts 

 and opinions have been quoted. An apology is scarcely needed for giving 

 a short resume of the facts known about the great star Alpha Centauri; 

 accordingly, a very brief history of this remarkable object, from Lacaille's 

 time (1750) to the present, has been given. 



The instruments used were an 8^-in. reflector, by Browning, and a 

 4|^-in. equatorial of superior quality. The measures of angles and distances 

 have been obtained by the methods described in my paper in last year's 

 " Transactions."* The angles of position will, I have little doubt, be found 

 to be good, but the atmosphere has not been steady enough of late to admit 

 of the best use being made of oblique transits. I have, however, little 

 doubt that such measures of distances as are given will be found to be very 

 satisfactory approximations to the truth. For the spectroscopic work 

 recorded in this paper I have used an admirable little star-spectroscope, by 

 Browning. This instrument has enabled me to determine, quite satis- 

 factorily, the class to which the stars examined belong, and, in many 

 instances, to say that the spectrum lines of certain elements are probably 

 present. As, however, the means at my disposal did not permit me to 

 make accurate measures of the positions of lines, my work in this depart- 

 ment should be looked upon as the results, so to speak, of a " flying- 

 survey," useful perhaps, in its way, but to be superseded when more 

 thorough and accurate determinations can be obtained. 



It should be stated, however, that, while depending on eye estimation 

 alone, it would be very unsafe for an observer to say, that a conspicuous line, 

 for instance, in the greenish blue of the spectrum of a certain star was cer- 

 tainly the F. hydrogen line ; yet it is unhkely that a practised eye, one trained 

 to recognize the position of certain lines in spectra that have been already 

 measured, could be mistaken, in any large proportion of cases, in picking 

 out, say, the principal Fraunhofer lines in a stellar spectrum. On the 

 whole, it seems to me that such determinations as are given in this paper, 

 are not without a real value, if carefully made. Many years must elapse 

 before the lines in the spectra of the Southern stars can be accurately 

 measured by methods like those employed by Dr. Huggins. In the mean- 

 time such results as those here given are all that are available. These 



* Trans. N. Z. Inst., Vol. XI., Art. X. ~~ 



