UNIVERSITY OF VIRGINIA PUBLICATIONS 



BULLETIN OF THE PHILOSOPHICAL SOCIETY 



SCIENTIFIC SECTION 



Vol. 1, No. 4; pp. 85-126 June, 1910 



NEW POSITIONS OF THE STARS IN THE HUYGHENIAN 

 REGION OF THE GREAT NEBULA IN ORION 



From Observations made at the Leander McCormick Observatory.* 



BY 



RALPH E. WILSON. 



CONTENTS. 



I. InTEODTjCTION PAGE 



Review of previous work: Herschel, 18.34-8; W. G. Bond, 1847-8; 

 Lassell, 1854; Liapunoff and Struve, 1862; G. P. Bond, 1859-65; 

 Br. Meyermann. 1905 — Method of work — Pitch of micrometer screw 

 — ^New stars — Precessions — Conclusions 35 



II. ObSEEVATIOKS CF ruNDA:\IENTAL STARS AND COMPUTATION OF THEIE 



Definitive Positions 93 



III. Observations — 



With reference to 628 99 



With reference to 558 110 



With reference to 669 Ill 



With reference to 685 113 



Miscellaneous 116 



IV. Catalogue of Positioks 119 



V. COMPAEISON with OtHEK AUTHORITIES . 120 



VI. Notes — Identification of H51 — Vaeiabiutt of 654 — ^^^isibility of 625. 125 



PART I. 



introduction. 



The first survey- of the Great Nebula in Orion for star positions was 

 made b.y Sir John Herschel at the Cape of Good Hope in the years 1834^8. 

 This survey was made for the purpose of plotting the stars on a drawing of 

 the nebula and included 150 stars, some of which were faiat. The posi- 

 tions of the stars with reference to © Orionis were determined by eye 

 estimates of position within the "skeleton" triangles, the vertices of which 

 were determined by micrometrical measurement. The differences in right 



*Read before the Scientific Section of the University of Virginia Philosophical 

 Society at its meeting in May, 1910. Presented to the Faculty of the University of 

 Virginia in partial fulfilment of the requirements for the degree of Doctor of 

 Philosophy. 



