﻿F. 
  H. 
  Bigelow 
  — 
  Solar 
  Corona. 
  

  

  

  

  

  Corona 
  

  

  of 
  Dec. 
  22, 
  1889. 
  

  

  

  

  

  Ray. 
  

  

  N 
  

  

  E. 
  

  

  N 
  

  

  W. 
  

  

  s. 
  

  

  w. 
  

  

  S 
  

  

  E. 
  

  

  

  1 
  

  

  30 
  a 
  

  

  25' 
  

  

  28° 
  

  

  51' 
  

  

  31° 
  

  

  15' 
  

  

  31° 
  

  

  30' 
  

  

  

  2 
  

  

  25 
  

  

  33 
  

  

  25 
  

  

  11 
  

  

  27 
  

  

  19 
  

  

  31 
  

  

  56 
  

  

  

  3 
  

  

  30 
  

  

  33 
  

  

  29 
  

  

  

  

  28 
  

  

  14 
  

  

  31 
  

  

  41 
  

  

  

  4 
  

  

  27 
  

  

  13 
  

  

  26 
  

  

  1 
  

  

  26 
  

  

  59 
  

  

  31 
  

  

  14 
  

  

  

  5 
  

  

  30 
  

  

  15 
  

  

  33 
  

  

  56 
  

  

  29 
  

  

  10 
  

  

  32 
  

  

  14 
  

  

  

  6 
  

  

  30 
  

  

  17 
  

  

  34 
  

  

  8 
  

  

  34 
  

  

  25 
  

  

  32 
  

  

  20 
  

  

  

  7 
  

  

  31 
  

  

  19 
  

  

  34 
  

  

  17 
  

  

  36 
  

  

  37 
  

  

  33 
  

  

  22 
  

  

  

  8 
  

  

  28 
  

  

  43 
  

  

  38 
  

  

  17 
  

  

  36 
  

  

  15 
  

  

  

  

  

  9 
  

  

  35 
  

  

  55 
  

  

  ■39 
  

  

  17 
  

  

  

  

  

  

  

  10 
  

  

  38 
  

  

  1 
  

  

  -- 
  

  

  -" 
  

  

  -- 
  

  

  -- 
  

  

  -- 
  

  

  -- 
  

  

  Mean 
  

   31 
  35 
  

  

  

  30 
  

  

  49 
  

  

  32 
  

  

  6 
  

  

  31 
  

  

  24 
  

  

  32 
  

  

  2 
  

  

  From 
  this 
  we 
  proceed 
  to 
  the 
  location 
  of 
  the 
  coronal 
  poles* 
  

   or 
  the 
  points 
  on 
  the 
  surface 
  of 
  the 
  sun 
  at 
  which 
  the 
  axis 
  of 
  

   polarization 
  pierces 
  it. 
  

  

  The 
  results 
  are 
  independent 
  of 
  each 
  other 
  as 
  regards 
  differ- 
  

   ent 
  coronas, 
  and 
  the 
  two 
  hemispheres 
  are 
  also 
  independent 
  

   for 
  the 
  same 
  corona. 
  

  

  

  North 
  Pole. 
  

  

  

  

  South 
  Pole. 
  

  

  

  Long. 
  

  

  Lat. 
  

  

  

  Long. 
  

  

  Lat. 
  

  

  July 
  29, 
  1878, 
  

  

  83° 
  18' 
  

  

  85° 
  

  

  12' 
  

  

  

  185° 
  4' 
  

  

  83° 
  49'" 
  

  

  Jan. 
  1, 
  1889, 
  

  

  73 
  26 
  

  

  84 
  

  

  25 
  

  

  

  174 
  29 
  

  

  86 
  22 
  

  

  Dec. 
  22, 
  1889, 
  

  

  36 
  19 
  

  

  87 
  

  

  

  

  

  134 
  52 
  

  

  86 
  2 
  

  

  Mean 
  latitude, 
  

  

  85 
  

  

  32 
  

  

  85 
  24 
  

  

  

  

  

  Difference 
  in 
  

  

  Longitude. 
  

  

  

  

  July 
  29, 
  1878 
  

  

  

  

  101 
  c 
  

  

  ' 
  46' 
  

  

  

  

  Jan. 
  1, 
  1889, 
  

  

  

  

  100 
  

  

  53 
  

  

  

  

  Dec. 
  22, 
  1889, 
  

   Mean 
  difference, 
  

  

  

  98 
  

  

  33 
  

  

  

  

  100 
  

  

  24 
  

  

  

  The 
  axis 
  of 
  polarization 
  is 
  therefore 
  at 
  the 
  surface 
  of 
  the 
  

   sun 
  about 
  4-§-° 
  degrees 
  from 
  the 
  axis 
  of 
  rotation, 
  and 
  the 
  

   southern 
  end 
  of 
  it 
  precedes 
  by 
  about 
  100 
  degrees 
  in 
  longi- 
  

   tude. 
  These 
  coordinates 
  of 
  latitude 
  and 
  longitude 
  are 
  al- 
  

   ways 
  referred 
  to 
  the 
  plane 
  of 
  the 
  sun's 
  equator, 
  considered 
  

   as 
  celestial, 
  and 
  from 
  the 
  ascending 
  node 
  of 
  the 
  sun's 
  equator 
  

   on 
  the 
  ecliptic, 
  that 
  is 
  from 
  the 
  point 
  whose 
  longitude 
  is 
  74° 
  

   from 
  the 
  vernal 
  equinox 
  on 
  the 
  plane 
  of 
  the 
  ecliptic. 
  These 
  

   coordinates 
  are 
  therefore 
  celestial 
  and, 
  being 
  independent 
  of 
  

   solar 
  conditions, 
  indicate 
  the 
  position 
  of 
  the 
  axis 
  of 
  polarization 
  

   without 
  any 
  complications. 
  A 
  computation 
  of 
  the 
  distance 
  

   apart 
  in 
  a 
  great 
  circle, 
  from 
  the 
  center 
  of 
  the 
  sun, 
  of 
  the 
  north 
  

   and 
  the 
  south 
  coronal 
  poles 
  gives 
  us 
  for 
  our 
  three 
  coronas 
  : 
  

  

  