Optical follow-up of the blazar BL Lac in August-September 2020

Optical multiband observations of the blazar BL Lac reveal that on August 21 it reaches its maximum brightness at a magnitude R of 11.9, value never recorded before, and shows an evident intra-night variability.

The observations were performed from:

• Astronomical Observatory of the University of Siena (V, R, I)
  by Alessandro Marchini
• Hypatia Astronomical Observatory, Rimini (V, R)
  by Fabio Mortari
• OACT Astronomical Observatory of Catania – Serra La Nave (B, V, R, I)
  by Antonio Frasca
• OAPM Astronomical Observatory of Montarrenti, Sovicille, Siena (CR)
  by Simone Leonini
• WBRO Wild Boar Remote Observatory in San Casciano Val di Pesa, Florence (V, R)
  by Antonio Frasca, Giuseppe Marino, Riccardo Papini

We provide below the complete lightcurve with all the multiband observations and some single-night ligthcurve to show the intra-night variability.