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GCN Circular 29269

GRB 210104A: iTelescope optical upper limit
2021-01-06T10:19:18Z (3 years ago)
Filipp Dmitrievich Romanov at Amateur astronomer <>
I observed the field of GRB 210104A (Troja et al., GCN Circ. 29233)
with remote telescope T11 (0.50-m f/6.8 reflector + CCD + f/4.5 focal
reducer) of iTelescope.Net in New Mexico Observatory. Three images
with AstroDon Luminance filter and with 300 seconds exposure time were
obtained on 2021-01-05. Start time of exposures: 06:46:48 UT (~19.3 h.
after trigger; Binx1), 06:52:21 UT (Binx2) and 06:57:44 UT (Binx1). I
did not detect any optical transients (magnitude limit of about 21.0
in stacked image).
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