Observations of a Major Outburst of BL Lacertae in the Active Galactic Nuclei Monitoring Program in the Center for Automated Space Science

BL Lacertae (BL Lac) is the prototype for a class of Active Galactic Nuclei (AGN) known as BL Lac objects. These objects are characterized by a featureless optical continuum that is both highly polarized and extremely variable. Historically, this object is known to have an optical variability range of 5 magnitudes (Webb, et al., 1987, Carini, et al. 1992) and exhibits episodic periods in which the source is observed to be bright (V = 12.0) and other periods when the source is observed to be quite faint (V = 16.5). In May, 1997, we found, in the course of our routine monitoring of these objects, that BL Lac was in an elevated state, with a V magnitude peaking near V = 12.5. The purpose of this paper is to report on our observations of the behavior of the optical continuum flux of BL Lac during this major outburst.