TITLE:   GCN CIRCULAR
NUMBER:  34469
SUBJECT:  GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
DATE:    23/08/17 19:51:04 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 observed the field of GRB 230816A (Siegel et al., GCN 34450) 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 18:55 UT of 2023/08/16, after about 2,45 hours after the GRB trigger, at the end of twilight with clear skies, with principal telescope  SC 0.35 f/10 with focal reduced + CCD Sbig ST10 XME
I took 25 image of 240 sec each. All images are unfiltered, calibrated with masterdark and masterflat,stacked with Tycho Tracker software
We have detected a faint  source of magnitude 19.1 G at the enhanced position reported by Swift-XRT (Siegel et al., GCN 34450, P.A. Evans et al., GCN 34462) and by optical telescopes ( A. S. Moskvitin et al GCN 34456., N. Pankov et al GCN 34457., Mohammad Odeh et al GCN 34458., S. Klose et al GCN 34459., R. Kumar et al GCN 34460)
at following position

RA      (J2000.0)  21h 53m 46.87s 
Decl.   (J2000.0) +37° 51' 14.7"  

Photometry and astrometry on stack of 13 images each of 240 sec

GRB 230816A KC2023 08 16.88481 21 53 46.87 +37 51 14.7          19.1 G      C82    
 



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



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