l^S Royal Astronomical Society. 



Letter from the Rev. W. R. Dawes. 



" On the first of the last month, while tracing the southern limits 

 of the great nebula in Orion, ray attention was attracted by the ap- 

 pearance of the star which stands on the point of the ^roJoscis wq/or. 

 With my 8|-foot equatoreal, power 195, the star was distinctly se- 

 parated into two, whose magnitudes were carefully estimated to be 

 the eighth and ninth. I have since searched in vain for any notice 

 of the duplicity of this star; yet it must have come under the eye 

 of every observer who has scrutinized the ramifications of this most 

 extraordinary of the nebula?. In the map of the regions and stars 

 of the nebulae, presented by Sir John Herschel to the Astronomical 

 Society in 1826, and contained in vol. ii. of the Memoirs, this star 

 is inserted and denominated A. The same designation is given to 

 it in the catalogue of the stars in the nebula given by Sir John in 

 page 28 of his Results of Astronomical Observations made at the 

 Cape, in which it stands as No. 135. It is there called C"7 magni- 

 tude, which is far brighter than it appears in this latitude : yet its 

 identity is unquestionable. Though one of the most Conspicuous 

 stars in that part of the nebula, and inserted with perfect accuracy, 

 from micrometrical observations in the beautiful plate in Sir John's 

 volume of Results, yet no intimation is given of its being double. 

 Neither does it appear in the catalogue of double stars, observed 

 with the 20-foot reflector. It seems scarcely probable, that if, ten 

 years ago, it presented its present appearance, it should not have 

 been recognized under the power of the 20-foot reflector, and withirf 

 30° of the zenith. This would perhaps be more extraordinary than 

 that it should have escaped detection by Mr. Cooper with his gigantic 

 refractor, or hy Dr. Lamont with the large telescope of 11^ inches 

 aperture at the Royal Observatoiy at Munich (whose observations of 

 the nebula are specially referred to by Sir John Herschel), or by 

 Struve at Dorpat, or finally by De Vico at Rome, who seems to have 

 paid great attention to this object, and in whose picture the star in 

 question appears as of the eighth magnitude, which is also assigned 

 to it by Lalande, in whose catalogue it stands as No. 10567. The 

 unavoidable inference would seem to be, that the star must have 

 emerged from a single state within the last ten years. But if its 

 change has been so rapid, it is surprising that it was never observed 

 to be double previously to its closing, either by Struve in his sweeps 

 for double stars, or by the scrutinizing eye of Sir W. Herschel, who 

 brought some of the largest and most perfect of telescopes to bear 

 upon it. If, on the other hand, the star has always been as distinctly 

 double as it is now, then it would be difficult to say what amount of 

 non- observation may be received as conclusive evidence of non-ex- 

 istence. The object is, at any rate, one of peculiar interest ; and I 

 would earnestly request attention to it by such observers as possess 

 instruments competent to its satisfactory measurement. Its mean 

 place for 1848-0 is R.A. 5^ 28"^ 27^; N.P.D. 95° 43' 47"." 



The star Weiss xx. 122, supposed to be missing, is inserted in the Berlin 

 Map, Mora xix. published in 1840.— (R. W. R.) 



