2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/8722Calibrated Tully-Fisher relations ''absolute magnitude - HI line width'' for spiral galaxies oriented edge-on are derived from published data. The slope of the linear fits, especially in R- and I- bands, is close to the value of -10, as predicted by the theory. The standard errors of the relations in B, V, R and I bands are 0.40, 0.36, 0.31 and 0.34 mag, corresponding to relative distance errors of 18%, 17%, 14% and 16%, respectively. The magnitude of an edge-on galaxy appears to be a good distance indicator.7 pages, 2 figures, published in Comptes rendus de l`Academie bulgare des Sciences, Tome 57, No 6, 2004Astrophysicstext