I have not corrected for the heliocentric redshift in these data.

**************************************************
Perr must stand for photon noise error.
I assume no reddening correction either

NGC 628 = M74
heliocentric velocity
from lines in sn spectra  +631 km/s  iauc 7822 S. Smartt & P. Meikle
from Leda  in radio       +656 km/s
from Leda  in optical     +639 km/s
from Leda  mean           +656 km/s

Foreground extinction in
B from Leda/Schlegel   0.30
E(B-V)=.30/4           0.075
E(B-V)=.30/4.1         0.073  See Cardelli p. 249
Paolo E(B-V)           0.08


**********************************************

Polarization  2002 feb 8

lambda(A), q(%), u(%), P(%), theta(deg), Perr.

END:
  5059.97803  0.398400009
  5307.79883  0.632300019
  5443.58203  0.579599977
  5551.021  0.681800008
  5665.11621  0.758000016
  5785.53076  0.305000007
  5872.9668  0.599399984
  5943.37695  0.785300016
  6010.17822  0.748700023
  6078.64697  0.686699986
  6139.24121  0.588100016
  6190.88086  0.589900017
  6236.56104  0.663100004
  6284.60986  0.586799979
  6328.46924  0.501900017
  6369.02979  0.549600005
  6409.64307  0.612399995
  6450.  0.65109998
  6490.47021  0.617399991
  6531.18018  0.605799973
  6571.39697  0.621299982
  6611.88916  0.485000014
  6652.5  0.541100025
  6692.85498  0.606599987
  6735.93604  0.717999995
  6784.06299  0.880800009
  6830.38281  0.906899989
  6881.45801  0.776899993
  6933.18311  0.831399977
  6976.58789  0.848399997
  7017.25195  0.943799973
  7057.71582  0.720899999
  7098.24219  0.699800014
  7134.12305  0.762300014
  7168.72119  0.784399986
  7201.88281  0.803799987
  7236.45215  0.796299994
  7268.93408  0.631600022
  7304.04102  0.80309999
  7336.32812  0.861899972
  7371.35107  0.785600007
  7403.62207  0.724399984
  7440.93408  0.899399996
  7485.49414  1.06920004
  7535.91211  0.946399987
  7601.89209  0.389899999
  7677.47607  0.658399999
  7718.97412  0.689400017
  7759.396  0.510999978
  7800.24707  0.445300013
  7840.19287  0.711499989
  7880.55713  0.773500025
  7921.25195  0.886799991
  7964.03418  1.10140002
  8014.63721  1.26880002
  8071.93018  1.64639997
  8142.48584  2.24580002
  8228.45117  1.33539999
  8308.00586  0.582599998
  8365.25293  0.554700017
  8403.70215  0.429199994
  8433.99609  0.42840001
  8460.8584  0.492500007
  8485.92578  0.471700013
  8503.93848  0.542299986
  8526.44824  0.458600014
  8544.4209  0.550000012
  8561.90039  0.562600017
  8575.40039  0.352200001
  8588.90039  0.30340001
  8602.40039  0.603999972
  8615.90039  0.587300003
  8629.40039  0.49939999
  8642.90039  0.655200005
  8656.40039  0.594699979
  8669.90039  0.517099977
  8683.40039  0.594600022
  8701.59082  0.486799985
  8719.58398  0.478199989
  8742.04492  0.517499983
  8760.00781  0.479200006
  8782.46191  0.453900009
  8805.19043  0.394199997
  8832.42969  0.543500006
  8859.49707  0.4903
  8886.44531  0.352999985
  8913.34473  0.371499985
  8942.47461  0.557200015
  8979.93066  0.515399992
  9020.95801  0.525300026
  9064.57031  0.447699994
  9111.64648  0.704299986
  9160.51758  0.462099999
  9203.87305  0.455799997
  9243.96582  0.50819999
  9286.29004  0.591499984
  9346.90137  0.58859998
  9423.75391  0.634500027
  9509.68848  0.408399999
  9600.93262  0.547599971
  9699.29297  0.712800026
  9803.44727  0.620199978
  9921.70508  1.2471
  10059.1826  1.20550001