Smithsonian Report. 1942. — Fleming 



PLATE 16 



Photographs of the Aurora Borealis Which Accompanied the Geomagnetic Storm 



OF September 18. 1941. 

 (All times are mean 75° west meridian.) 



(A) 19''29™, Ithaca, N. Y.; aimed at Pegasus, nearly due east; sliows that the rays make the dip angle with respect to the 

 horizon; corona appears to have been located about 17° south of the zenith; exposure 11) seconds. ( I'hotograph by C. AV. 

 Gartlein and courtesy of National Geographic Society.) (jB) Looking duo wfst from lop of Huildiiik' J), Harvard 

 College Observatory, Cambridge, Mass., this intense red patch appeared behind a church steeple at iyi'50">. (Photo- 

 graph by R. Newton Mayall.) (C) 20112.5™, Patchoque, N. Y.; exposure 16 to 20 seconds. (Photograph by E. Dayton 

 Thorne.) (D) 20i'50m, Patchoque, N. Y.; exposure 10 to 20 seconds, f/3.5. (Photograph by E. Dayton Thorne.) 

 (E) 20h40m, Patchoque, N. Y.; exposure 10 to 20 seconds, f/3.5. (Photograph by E. Dayton Thorne.) {F) Made at 

 Saranac Inn, N. Y.; direction northwest by north; exposure 20 seconds or more. St. Regis Mountain, 10 miles away, 

 attests the intensity of general illumination when this shot was made about midnight. (Photograph by Ernest T. 

 Pearson.) 



