TITLE: GCN GRB OBSERVATION REPORT NUMBER: 120 SUBJECT: SGR1900+14 field optical observations DATE: 98/06/30 17:05:16 GMT FROM: Arne A Henden at USNO/USRA A. Henden, C. Luginbuhl and F. Vrba (U.S. Naval Observatory Flagstaff Station) report that they have obtained extensive I-band and J-band observations of the near-IR sources and surrounding field associated with SGR1900+14 both before and after the recent onset of activity. None of the observations coincide with bursts detected by BATSE, and no unusual photometric behavior has been detected though reductions are ongoing. A new eclipsing binary has been detected nearby, however, at RA 19:07:16.85 DEC +09:18:50.4 (J2000), about 39.0 arcseconds SE of the M supergiant pair. The binary is about I=19.1 out of eclipse, and has been observed through several eclipses of about 0.4mag depth. The period is either about 1.07day or some integer fraction. This binary appears as the star labelled 'J' in Figure 1 of Vrba et. al. ApJ 468:225 (1996). We bring this star to the attention of other observers in the hope that it not send anyone on a wild goose chase if it is detected as a variable in observations of this gamma-ray burst location. This message is quotable in publications.