Optical photometry of BL Lac

ATel #5558; E. Ovcharov (SU, Bulgaria), A. Kurtenkov (IA BAS, Bulgaria), P. Enikova (IA BAS, Bulgaria), G. Ganchev (SU, Bulgaria), V. Bozhilov (SU, Bulgaria), Ts. Tsvetkov (SU, Bulgaria), Ts. Genkova (SU, Bulgaria)
on 7 Nov 2013; 02:09 UT
Credential Certification: Evgeni Ovcharov (evgeni@phys.uni-sofia.bg)

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Following the announcements of NIR brightening of BL Lac (ATel #5518, ATel #5550), we performed optical observations of BL Lac on Oct 29 and Nov 02. The observations are carried out with the 0.35m Newton telescope + CCD STL11000M at the Student Astronomical Observatory - Plana, Bulgaria (long=23.4269, lat=+42.4764, alt=1220m).

The available BVRI-magnitudes are:

2013 10 29.798 UT, B=14.76+/-0.01
2013 10 29.803 UT, V=13.70+/-0.01
2013 10 29.787 UT, R=13.09+/-0.01
2013 10 29.792 UT, I=12.33+/-0.01

2013 11 02.827 UT, B=14.69+/-0.01
2013 11 02.833 UT, V=13.60+/-0.01
2013 11 02.821 UT, R=13.04+/-0.01
2013 11 02.823 UT, I=12.27+/-0.01