OAO 1653-40

P. Byrne, A. Levine, F. Lang, C. A. Dobson, J. P. Doty, S. K. Howe, F. A. Primini, W. A. Wheaton and W. H. G. Lewin, Massachusetts Institute of Technology, report the position of a hard x-ray source detected in the region of OAO 1653-40. Both spectral and positional evidence strongly indicate that this source is the 38-s pulsar (IAUC 3342). The four corners of the error region (1.5-sigma level of confidence) are given by R.A. = 16h54m, Decl. = -41o40'; 16h54m.3, -41o10'; 16h58m.6, -41o16'; 16h58m.3, -41o45' (equinox 1950.0). The observations were made with the UCSD/MIT HEAO-A4 experiment in the spinning mode. The error box clearly excludes V861 Sco, in agreement with the HEAO-A3 result (IAUC 3342). When the A4 detector was pointed in the above direction, 38-s pulsations were detected up to about 80 keV.