JPL EARTH OCCULTATION ANALYSIS OF THE GALACTIC-CENTER REGION DURING FLARING OF 1E-1740.7-2942

We present preliminary results of a search for flaring of the gamma-ra y source 1E 1740.7-2942 above 300 keV using the JPL-EBOP package on BA TSE data. We selected two periods, 1-19 October 1991 and 19-20 Septemb er 1992, corresponding to SIGMA observations of a transient high energ y feature in the spectrum of 1E 1740.7-2942 around 450 keV. For the fi rst period, we find an integrated 300-600 keV flux consistent with SIG MA observation. Below 200 keV, the interpretation is uncertain because of potential source confusion with BATSE. For the second period, the sensitivity of the current JPL-EBOP package does not allow us to put s trong constraints on this similar to one-day long flaring although no flux variation above 300 keV is observed during a 13-day period includ ing this event with a one-day one-sigma sensitivity of similar to 10(- 3) ph cm(-2) s(-1).