Please correct following observation in [vsnet-obs 4125 ] SN2002er 20020906.869 139CR Nic Should be read: SN2002er 20020906.869 142CR Nic US 152 G 3.3" 120s 45° http://vsnet.astrosurf.com/snweb/2002/02er/images/02erNI_C200209062052.htm A large discrepancy appeared between the measures published by J. Nicolas and J. B. de Vanssay, members of the groupe CCD-Web (http://fr.groups.yahoo.com/group/CCD-Web/). As members of the group always report the star they used as reference, it appeared that J. B. de Vanssay used the star referenced as 143R on O. Trondall image, while J. Nicolas used the star referenced 150R and, in a further study, J. C. Pelle ( mailto:jcpelle@mail.pf ), taking into account color term and magnitude term in the USNO magnitudes, concluded that both stars where in error with a total discrepancy of 0.57 mag. J. C. Pelle proposes the following corrections OT 143 -0.20 mag i.e. 14.10 OT 150 +0.27 mag i.e. 15.27 This accounts for a 0.47 mag difference. J. C. Pelle explains the remaining 0.10 magnitude as follow Color term +0.025 mag Magnitude term +0.077 mag J. C. Pelle also recommends using as reference the USNO star at the East of the SN RA DC Mag_B Mag_R V-R Dist(°) 17 11 43.4 +08 00 33 16.30B 15.20R +0.40 0.057 which appears to have a magnitude in good accordance with the remaining of the field. Software SNWeb provided by Jean-Claude PELLE ( jcpelle@mail.pf ) Jean-Marie LLAPASSET Obs 635 Perpignan (France) http://perso.wanadoo.fr/jm.llapasset http://vsnet.astrosurf.com/snweb/