TITLE:   GCN CIRCULAR
NUMBER:  35677
SUBJECT:  GRB 240204A: Osservatorio Astronomico Nastro Verde upper limit
DATE:    24/02/05 18:30:30 GMT
FROM:    Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy - MPC Code C82 <osservatorionastroverde@gmail.com>

Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy
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 (Universita' degli Studi Di Salerno)
report: 

We image the field of GRB 240204A (Swift triggered on the Fermi/GBM, GCN 35664; Cenko et al., GCN 35666; Pozanenko et al., GCN 35670)
with telescope of Nastro Verde Observatory - Sorrento (Naples), Italy. Member of: 
AAVSO - American Association of Variable Star Observers.
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.
AstroCampania Associazione

The observations started at 18:16 UT of 2024/02/04, after about 3 hours after the GRB trigger, at the end of twilight
with principal telescope  SC 0.35 f/10 with focal reduced + CCD Sbig ST10 XME
I took 104 image of 60 sec each. All images are unfiltered, calibrated with masterdark and masterflat,stacked with Tycho Tracker and Astrometrica software
We have not detected any clearly visible sources, up to 20th magnitude with clear skies.
   Start T0+                   End T0+         Rlim
18:16:19 UT            21:15:19 UT      19.5

We did not found any optical counterpart in the error box of the XRTcandidate.




Magnitudes were estimated with the Gaia DR2 cat. and 
are not corrected for galactic dust extinction.



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