In the night from 11 to 12 May we were able to measure a strong increase in the optical brightness of AGN S4 0954. We have only had this AGN in our measurement programme for almost two years. Shortly after the detection, Tom Balonek from Colgate University in New York sent us a hint about this increase in brightness via the e-mail distribution list of the Whole Earth Blazar Telescope (WEBT) Collaboration. Italian scientists were also able to measure this burst of brightness. In the following nights, S4 0954 was still closely monitored by the scientists from New York, Siena and Milan as well as by us. On 14 May, in a joint effort, an Astronomers Telegram on this event was published.
S4 0954 belongs to the subgroup of BL Lacertae objects, a group of active galactic nuclei that are very bright. Scientists assume that in these objects the accretion disk is more or less perpendicular to our line of sight, so that we look almost directly into the jet. This also explains the relatively high brightness of these celestial objects.