GCN Circular 23130

I. Carrasco (Univ. de Malaga), Y. Hu, E. Fernandez-Garcia, J. C. Tello 
and A. J. Castro-Tirado (IAA-CSIC), D. Hiriart and W. H. Lee (UNAM), S. 
Jeong and I. H. Park (SKKU), M. D.
Caballero-Garcia (ASU-CAS, CZ) and R. Cunniffe (Inst. of Physics, CZ) on 
behalf of a larger collaboration, report:

The 60cm BOOTES-5/JGT robotic telescope at Observatorio Astronomico 
Nacional in San Pedro Martir (Mexico) automatically responded in 22s 
(and 52s after the GRB onset) to the
Swift trigger of GRB 180812A (Lien et al., GCNC 23129). The first image 
(10s exposure, r-band) was obtained at 08:23:25 UT. At the position of 
the Swift X-ray afterglow, a variable optical source with r about 17 mag 
is detected, which is fading in brightness in the late images. Therefore 
we propose this source to be the optical afterglow to GRB 180812A. 
Spectroscopic observations are encouraged.

We thank the staff at Observatorio Astronomico Nacional in San Pedro 
Martir for its excellent support.