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 mar 07

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

END:
  5081.23193  114.428001
  5341.64111  114.966003
  5485.604  130.138
  5611.15479  123.082001
  5750.38184  114.632004
  5863.66309  112.015999
  5950.28418  124.598
  6030.15576  132.285995
  6105.80078  134.565994
  6173.87305  126.306
  6233.27979  120.450996
  6287.16797  123.480003
  6341.07617  121.948997
  6395.52881  121.122002
  6449.15283  122.514999
  6503.29297  125.174004
  6557.06689  127.077003
  6610.95703  128.610001
  6664.96582  130.662994
  6718.9751  130.085007
  6772.99805  137.942993
  6826.98486  132.742004
  6889.04004  136.919006
  6949.07617  135.660995
  7002.80518  131.378998
  7050.04492  136.697006
  7090.521  129.285995
  7130.99512  135.436996
  7170.97803  135.466003
  7212.52979  127.288002
  7252.65283  133.212997
  7292.88818  132.677994
  7333.35107  130.964996
  7373.66992  131.009995
  7413.93896  132.294006
  7460.79199  133.837006
  7521.021  133.712997
  7597.1792  131.636993
  7680.14404  117.43
  7724.82617  117.088997
  7765.38623  113.317001
  7806.13379  112.543999
  7846.18408  129.190994
  7893.25098  121.887001
  7947.13721  128.384995
  8001.00879  134.675995
  8060.82617  140.841003
  8140.93799  138.317993
  8246.49023  135.983994
  8335.27441  119.204002
  8387.28125  125.071999
  8427.69727  122.150002
  8460.85254  127.197998
  8487.84961  113.571999
  8514.91895  112.505997
  8541.84277  112.918999
  8568.77441  122.929001
  8595.63867  123.129997
  8622.59863  116.143997
  8649.56836  123.998001
  8676.56543  116.898003
  8703.5459  114.014999
  8730.45508  117.453003
  8757.4209  124.353996
  8784.40723  123.543999
  8811.4541  129.608994
  8845.21973  125.148003
  8885.64258  107.117996
  8925.96387  105.662003
  8966.30469  128.041
  9014.45215  117.720001