Observations of 500 Nebulae. 



99 



1865 Aug. 13. Sky tolerable; magn p 320. 



The n part of the ring brightest; strongly granulate, with sev not vF * .. seen 

 by momentary glimpses : 2 or 3 *... in the np part and two in the sf part of the ring 

 distinctly seen; at the interior m of the ring 2 -*... visible in the sp, and one in the 

 sf part. Halms * — al np the geometr C ? — momentarily visible : dull and plane- 

 tary. All these *... only so momentarily seen, that to adjust the micrometer-wire 

 upon them was quite impossible. The nf part of the ring very diffuse with nebs ra- 

 diations in the direction of the longer axis, which seem momentarily almost to de- 

 stroy the annular form. The C vacuity not inconsiderably nebs. The diam of the 

 outer ellipsis measured : 



in decl-circle = 58",8 (4). 

 Breadth of the ring measured = 11 ",7. 

 1867 Aug. 6. Sky not v favourable; magn p 210, 320, 480. 

 Halms C * distinctly seen without effort. The annulus strongly granulate ; 

 its nf end only momentarily well def. 



1870 Aug. 8. Sky not particularly favourable and in all cases too light for 

 that object, which is remarkably less B than for instance hl970; magn p 320. 



Twinkling stell points at the n outer m, which is best def. The diam of the 

 outer ellipsis obtained through comparison of the edges with the f *a : 



diam in decl-circle = 56",5 (5), 

 diam in par (pass) = 59"7 (12). 

 Immediate measures give : 



diam in decl-circle = 56", 1 (5). 

 Rem. h2023 never seen on sufficiently dark ground, wherefore of the sev F* ... 

 in the vicinity only the well known *a f in par obs. The cliff in decl, bet that * 

 and the geometr C of the neb, was 1867 determined by means of a great num- 

 ber of measures in the following manner. The micrometer-thread was so placed? 

 that its dist from the fixed thread was a little less than the diam in decl of the 

 neb, and this thread-system was then symetrically adjusted on the annulus. If then 

 c be the reading of the scale for the coincidence of the threads, and a — c - 

 scale-dist bet the threads; the reading of the scale corresponding to the C of the 

 annulus will be '/ 2 (c + u). If then the moveable thread be adjusted upon *a, 

 the refractor being left unmoved, and the reading of the scale be = ,i; the cliff 

 in decl sought will be 



p- % (c + u). 



I had thought, that this manner of pointing the C of the neb by means of 2 threads 

 would be much exacter than that of immediately adjusting a single thread upon 

 it. This supposition was however not confirmed, as the probable error in one 

 single measure in both cases is v nr the same = 0",8. The results of the two 

 methods of measuring meanwhile fully confirm each other, which gives an empirical 

 proof of the great exactitude, with ivhich a sigle thread can be adjusted upon the 

 geometr C of even a tolerably great discoid neb. 



GC.4473 ( = Hind Nova) v diffic to obs, as the C condens none or v uncertain. Sev 

 *... glimmering in the neby — r? 



