TITLE:   GCN CIRCULAR
NUMBER:  46280
SUBJECT: Optical Observations of GRB 261113A
DATE:    26/11/14 23:50:26 GMT
FROM:    J.H. Xu at AAVSO <hyena_eris@163.com>

I observed the field of GRB 261113A (A. Saccardi et al., GCN 46244) with an 28cm SCT in Chengde, Hebei operated by the Interestar network, ~10 min after trigger and 7min after notice. Six 300s exposures were taken in the Luminance filter (approximately 400nm to 700nm), with a mid-time of 2026-11-13 14:59:40 UT (about 28 min after the trigger). The optical afterglow  (Lin et al., GCN 46247) was detected in the stacked image, with an SNR of 14.8. I reduced the stacked image to a V band zeropoint using Tycho Tracker (Parrott, 2020), and measured the following Vega magnitude with hand-picked comp stars from the Atlas Star Catalog (Tonry et al., 2018).

Mid-time (UT) | Exp.time (s) | Mag | Mag error | Filter
14:59:40 | 6 x 300 | 19.52 | 0.1 | Luminance

The magnitudes were not corrected for Galactic extinction. The calibrated images are available on reasonable request.