GCN Circular 34419

L. Moretti and E. Pavoni (Leavitt Observatory), in a large collaboration with:
M.G. Dainotti (National Astronomical Observatory of Japan), 
Y. Niino (Tokyo University, Institute of Astronomy), 
K. Kalinowski (Aarhus University, Department of Physics and Astronomy),
B. De Simone (Università degli Studi Di Salerno)
report: 

We observed the field of GRB 230812B (Fermi GBM Team GCN, 34386; Roberts et al., GCN 34391
Not found
 
 
; Scotton et al., GCN 34392
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; Page et al., GCN 34394
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; Zheng & Filippenko, GCN 34395
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; Kuin et al., GCN 34399
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; Beardmore et al., GCN 34400
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; Casentini et al., GCN 34402
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; de Ugarte Postigo et al., GCN 34409
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, 34410
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) with the telescope of Leavitt Observatory, Italy. Member of: 

UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili, GRB section.
ATA - Associazione Tuscolana di Astronomia.

The observations began at 20:35 UT on 2023/08/13 (~1 day after the FERMI trigger), at the end of twilight, with our RC telescope D=250 mm F/D=8.

Weather conditions were good.

We took 9 images of 240 sec each. All images are unfiltered, calibrated with master dark and master flat, stacked with ASTAP software.

We detected the afterglow at the following position:
RA(J2000)  = 16h 36m 31.48s
Dec(J2000) = +47° 51' 32.1"

We measured its brightness of 20.78 +/- 0.2 mag in our coadd image in clear band, at a mid-time of 25.913 hours after the FERMI trigger, JD 2460170.36944. 

Magnitudes were estimated with the Gaia (BP) DR3 cat. and are not corrected for galactic dust extinction.

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