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:
  5121.86377  136.037994
  5402.63281  125.483002
  5569.5  129.552002
  5744.99316  136.854004
  5884.21289  126.084
  5983.55518  120.856003
  6079.13916  127.970001
  6167.88477  122.165001
  6240.07715  123.139
  6307.79883  124.492996
  6375.1748  125.887001
  6442.53906  125.32
  6510.11523  120.405998
  6577.08105  125.334
  6644.73877  135.582993
  6711.979  132.300003
  6779.68799  128.822998
  6852.43604  134.755997
  6929.81689  131.936996
  6996.14795  136.067993
  7056.90283  133.199997
  7110.95801  129.628006
  7164.8252  131.031998
  7219.06494  131.369995
  7265.9751  133.104004
  7306.38623  137.869995
  7346.68115  124.339996
  7393.36084  135.899994
  7453.45117  128.322006
  7527.29492  137.328003
  7638.97314  112.830002
  7718.26416  121.422997
  7772.17822  113.822998
  7826.00098  115.190002
  7879.68604  124.017998
  7940.12012  128.406998
  8013.5918  130.595001
  8106.47412  137.145004
  8225.24023  142.184998
  8329.55469  126.914001
  8394.82129  128.464005
  8441.2168  118.150002
  8481.52344  119.114998
  8514.94727  123.264
  8541.8584  112.382004
  8568.7998  117.190002
  8595.65039  122.050003
  8622.61523  121.065002
  8649.5752  120.061996
  8676.56543  120.68
  8703.53418  122.992996
  8730.45215  124.639
  8757.42188  127.143997
  8790.76367  116.907997
  8831.62988  119.959999
  8872.14453  110.822998
  8912.52734  100.526001
  8959.26172  111.318001
  9013.99805  122.846001