TITLE:   GCN CIRCULAR
NUMBER:  35460
SUBJECT: GRB 240101A: Terskol Zeiss-2000 optical observations
DATE:    24/01/02 16:26:17 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>

A. Volnova (IKI), P. Phorunzij (INASAN), A. Pozanenko (IKI),  N. Pankov (IKI, HSE), S. Belkin (IKI, HSE)  report on behalf of GRB IKI FuN:

We observed the GRB 240101A  (Cenko et al., GCN 35448) with Zeiss-2000   telescope of Terskol observatory starting on 2024-01-01 (UT) 16:10:24.   Within enhanced Enhanced Swift-XRT position (Beardmore et al., GCN 35452)  we do not detect any optical objects. However we marginally detected the object at coordinates (J2000) 00:41:23.50 +8:30:58.48, which is 3.4 arcsec from XRT position (Beardmore et al., GCN 35452). Preliminary photometry of the marginally detected object is following.

Date       UT start  t-T0     Filter Exp.    OT   Err. UL.    
                     (mid, days)      (s)         S/N 


2024-01-01 16:10:24  0.1823   R      19*60   23.7 2.0 23.0  


The photometry is based on the nearby PS1 stars photometry (Lupton transformations)
RA           Dec  c      R(Lupton)
00:41:22.24 +08:31:56.6  16.277  +/-  0.012
00:41:17.90 +08:31:41.5  18.013  +/-  0.014