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What 2 Cepheids are you talking about?
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You're joking, right? Read my post #244 above.
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I just wondered why you were suddenly claiming that I had calculated an angle between "2 Cepheids" when it really was two galaxies.
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Oooops. I gave the wrong link. Here is the correct one.
http://arxiv.org/ftp/astro-ph/papers/0408/0408348.pdf
Repeating my point:
Table III gives distances to 17 spiral galaxies in the Virgo Cluster determined using the Tully Fisher method (type dependent) and calibrated using the HKP Cepheids. The Table III values are from the Tully Fisher equations (6) and (7) which contain the error component.
From these are calculated distances of 28.1 Mpc to NGC 4343 and 12.6 to NGC 4569. The distances with error bars are 28.1 +/- 2.1 Mpc for NGC 4343, and 12.6 +/- 1.1 Mpc for NGC 4569. The difference of 15.5 (13.4 to 18.6) Mpc is approximately the distance between 2 galaxies within Virgo (the actual distance is slightly larger when accounting for the Right Ascension and Declination of each galaxy). This distance is far greater than "a couple of Mpc". So now we have reviewed a total of only about 20 of the 2000+ galaxies in Virgo, and found the cluster size to be at least 15.5 Mpc. This should suffice to illustrate the point.
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I haven't checked the errors you give against that paper, but they can not be correct. Even in the Tully & Pierce paper that dgruss has promoted in this thread it says that individual galaxies have a distance error of 15-20% in the Tully-Fisher method. Besides, The B-band TFR used in the linked paper has significantly more scatter than the I-band relation, resulting in larger distance errors.