TITLE: GCN CIRCULAR NUMBER: 40312 SUBJECT: GRB 250430A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit DATE: 25/05/02 06:35:58 GMT FROM: Giovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, Messina, Italy giovannicalapai@tiscali.it
Giovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, (Messina) Italy Member of: GRB/UAI Gamma Ray Burst Section of Unione Astrofili Italiani.
Report:
We imaged the field of GRB 250430A detected by Swift/BAT (Parsotan et al. GCN 40292), with the 11 inches Schmidt-Cassegrain (Celestron 11) telescope F/D=6,3.
The observations were started at 2025-04-30 21:32 UT (approximately 4.02 hours after burst) stacking a set of unfiltered CCD image.
We co-added 80 exposures of 60 sec each.
Start T0+ End T0+ CR lim 4.02 hour 6.85 hour 19.9
We did not found any optical uncatalogued object within the Swift error circle.
Magnitudes were estimated with the PanSTARRS cat. and are not corrected for galactic dust extinction.
Our upper limit is consistent with other observations reported by Kawabata et al. (GCN 40294), Odeh et al. (GCN 40295), Saccardi et al. (GCN 40301), Hagio et al. (GCN 40302), Quadri et al. (GCN 40303), Moretti et al. (GCN 40304), Atri et al. (GCN 40305), Komesh et al. (GCN 40307), Mo et al. (GCN 40308), Zheng et al. (GCN 40310), Li et al. (GCN 40311).
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