TITLE:   GCN CIRCULAR
NUMBER:  44341
SUBJECT: EP260416a: Ondrejov D50 optical detection
DATE:    26/04/18 19:52:07 GMT
FROM:    Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek@asu.cas.cz>

M. Jelinek, J. Strobl, F. Novotny, A. Malenakova and R. Hudec
(ASU CAS Ondrejov, CZ) report:                                                         
									
We observed the field of EP260416a (Hu et al., GCN 44307) with
the 50 cm robotic telescope (D50) of the Astronomical
Institute Ondrejov, near Prague, Czech Republic. We obtained 
a series of 120 s Sloan-r band exposures starting at 20:09 UT 
on 2026 April 17, i.e.  38.66 h after the initial trigger, and
combined 68 frames with a mean exposure time of 40.03 h after
the trigger.

The optical counterpart (Ducoin et al., GCN 44310; Li et al.,
GCN 44315; Hua et al., GCN 44318; Lee et al., GCN 44319; Zheng
et al., GCN 44321; Martin-Carrillo et al., GCN 44328; Li et
al., GCN 44334) is detected in the combined image. 

The preliminary AB magnitude of the object is r = 21.08 +/-
0.23, calibrated against the ATLAS catalog and not corrected
for Galactic extinction.
									
Our measurement is consistent with the continued fading of the
afterglow.