TITLE:   GCN CIRCULAR
NUMBER:  23284
SUBJECT: GRB 180930A: NOT optical upper limits
DATE:    18/10/01 08:00:35 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

Daniele B. Malesani (DAWN/NBI and DARK/NBI) and Ana Sagues (NOT) report 
on behalf of a larger collaboration:

We observed the field of GRB 180930A (Tohuvavohu et al., GCN 23279) with 
the Nordic Optical Telescope (NOT) equipped with the AlFOSC camera. 
Observations were carried out as soon as the field became visible from 
La Palma, starting on 2018 Oct 1.153 UT (14.95 hr after the GRB). A 
total exposure of 1500 s in each of the SDSS r and z filters was secured.

Inside the UVOT-enhanced GRB position (Osborne et al., GCN 23282), we 
detect no sources down to r = 23.5, z = 22.8 (both AB, calibrated 
against nearby stars from the Pan-STARRS survey).