The nucleus of 51P/Harrington suffered a major splitting event in Autumn 2001 discovered by amateur José Manteca. The light curve and separation of the fragments is examined based on data from the observers collaborating in the Spanish language ``Cometas_Obs'' mailing list, including a number of pre-announcement observations. There is some uncertainty in the epoch of the initiation of the split. Some evidence favours an earlier initiation than September 2001.