Measures of the Double Stars Contained in the Mensurae Micrometricae of F. G. W. Struve; Collected and Discussed with an Introduction Containing General Deductions, a List of Proper Motions of Fifty Faint Stars and Various Other Information in Respect to (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1906 Excerpt: ...inconsistent, they have been combined; the other measures are plotted as they stand. There can be no doubt of the binary character of this pair, and it ought to receive more general attention, the more so as it may now be expected to close up. Assuming that the positions previous to 1856 are in error, and that the motion can be represented from 1856 to 1902 along a straight line from A to B, then the motion along this line is--From 1856 to 1868, annual motion of 004 2 1457. R.A. io" 33- 31 Mags. 7-6 1 Colour: Yellowish N.P.D. 830 46' J 8-5 / Yellowish Lalande 20574. The measures can be well represented in direction by a straight line in position angle 3350; but when means are taken, and the motion along this line measured, there is evidence of orbital motion, e.g. From 1829 to 1847 the motion is-0168 per annum, 47 11 7o -oioo, 70 H 94 --0070 the motion decreasing as the distance increases, and hence we may regard it as a binary. Distance measures are of great importance, as the companion may have passed elongation. 1516. R.A. II11 8" 40-1 Mags. A 7 0 Colour: White N.P.D. i6o' J B75 J White When Lalande observed the stars A and B in 1790, the smaller star B preceded A by about 29," and in the Catalogue Lalande (F)' B is numbered 1830, while A is 1831. At the present time (1900) A precedes B by 20." The motion of B relative to A is well represented by the formulae deduced by Otto Struve in 1878--viz. A R.A. =-i'-3i8+o:407 (/--1850) A N.P.D.=-2-914 + 0-108 (/--1850) and is in agreement with that deduced from all the observations to 1899--viz. o"-424 in direction io5-o. The proper motion of A, according to Porter, is o"45 in direction 2870; hence this apparent motion ...