TITLE:   GCN CIRCULAR
NUMBER:  46099
SUBJECT: GRB 261029A: Optical detection with 60cm Panzhihua Telescope
DATE:    26/10/29 17:36:17 GMT
FROM:    Jiewei Zhao at SWIFAR, YNU <meow.jiewei.zhao@gmail.com>

Jiewei Zhao, Xinchao Wang, Brajesh Kumar, Wenyu Li, Guowang Du, Yuanpei Yang (SWIFAR, YNU), Bin-Bin Zhang, Kamil Nadaf (NJU), Kai Liao, Xinyu Wang, Xing Yao, Yang Zeng and Chunlai Zhang (SSO) report on behalf of a larger collaboration:

We observed the GRB 261029A field detected by Fermi/GBM  (Fermi GBM Team, GCN 46071) and SVOM/ECLAIRs (Goto et al., GCN 46072). The observations were initiated at 2026-10-29T13:38:33.40 (~12.19 hours after the trigger) with the 60cm Panzhihua Telescope located at the Sichuan South Observatory (SSO), China. A total of 10 frames with 300s exposure each were acquired in L band. 

We clearly detect the optical counterpart (O'Neill et al. GCN 46073; He et al. GCN 46078; Wang et al. GCN 46079; Cotter et al. GCN 46081; Álvarez et al., GCN 46083; Yin et al., GCN 46084; Shi et al., GCN 46088; Kang et al., GCN 46090; Ma et al., GCN 46092.; De et al., GCN 46093) in the stacked image. The L-band photometry result is presented in the following table: 

MJD (Exp_Start)	       MAG                          FILTER
61342.56844            20.23 +/- 0.15    	    L

Note that the expected Galactic extinction is not applied in our estimates.