ASCA MEASUREMENT OF THE HYDROGEN COLUMN DENSITY TO 1E-1740.7-2942

We report an accurate measurement of the hydrogen absorption column de nsity to the microquasar and annihilator Galactic black hole candidate 1E 1740.7-2942 near the Galactic center using data from ASCA observat ions. Two separate ASCA observations of this source, in 1993 and 1994 Fall, consistently give a best-fit hydrogen column density N-H similar to 8 x 10(22) cm(-2) with small dispersion. This value lies right in the middle of the range estimated by Chen et al. using ROSAT data, but significantly below previous estimates based on the SPARTAN and ARTP- SIGMA observations. It has important implications for the location of the source relative to the dense molecular cloud G-0.86-0.08 and the m ass limit on any potential companion.