TITLE:   GCN CIRCULAR
NUMBER:  46289
SUBJECT: iTelescope observations of GRB 260914A
DATE:    26/11/15 09:59:48 GMT
FROM:    J.H. Xu at AAVSO <hyena_eris@163.com>

I observed the field of GRB 260914A (Wang et al., GCN Circ. 45562) with T21 (0.43-m f/6.8 CDK) of iTelescope.Net at Utah Desert Remote Observatory ~52 min after trigger. Two 300s exposures were taken in the Luminance filter (approximately 400nm to 700nm), with a mid-time of 2026-09-14 12:09:46 UT (about 57 min after the trigger). The optical afterglow (Akl et al., GCN 45564; Palmerio et al., GCN 45565; Li et al., GCN 45566; Shi et al., GCN 45567) was detected in the stacked image, with an SNR of 7.2. 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
2026-09-14 12:09:46 | 2 x 300 | 19.95 | 0.19 | Luminance


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