TITLE:   GCN CIRCULAR
NUMBER:  3311
SUBJECT: GRB 050421: SLOTIS observations
DATE:    05/04/21 21:25:54 GMT
FROM:    Peter A. Milne at super-LOTIS  <pmilne@as.arizona.edu>

SUBJECT: GRB 050421: SLOTIS observations
FROM: P.A.Milne at Steward Observatory
                                                                        
                                                                        
P.A.Milne, G.G.Williams (Steward Obs), H.-S.Park (LLNL),
on behalf of the Super-LOTIS GRB team report:
                                                                        
On Apr 20/21, we observed the field of GRB 050421 
(SWIFT trigger 115135) starting at UT=08:01:56 (230m after the burst),
and again at UT=10:31:56 (480m after the burst) with the 0.6m SLOTIS 
telescope at Kitt Peak, AZ. We obtained 30 x 30-sec images during 
each observation.
                                                                        
Comparison of the two resulting co-added images to the relevant
DSS2 image reveals no new sources within the BAT error circle
(GCN 3301). No new source was detected at the location of
the potential counterpart reported by Bloom (GCN 3306),
Blake and Bloom (GCN 3310).
                                                                        
The first epoch was affected by the bright moon and high airmass.
The upper limit of a source in that field is about 17.5 magnitude.
The second epoch images were obtained under more favorable
conditions, and the upper limit of a source in that field is
about 20.0 magnitude.
                                                                        
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