New high-resolution, high-sensitivity Westerbork Synthesis Radio Telescope Hi synthesis observations of the spiral galaxy NGC 3631 are presented. In the total atomic hydrogen map, the spiral arms are well distinguished from the interarm regions, while the sensitivity allows detection of Hi in all but a few isolated regions of the areas between the

IAUC 6634 available at Central Bureau for Astronomical Telegrams.

Broadband UBVRI and narrowband H alpha and continuum images have been obtained for the Hickson compact group HCG 31 as part of an ongoing program devoted to the study of the star formation properties of galaxies in these groups. A spatially resolved analysis for the (U-B), (V-I), and (B-I) color maps has been performed, as well as for the U band, H

In the paper Model Color-Magnitude Diagrams for Hubble Space Telescope Observations of Local Group Dwarf Galaxies by A. Aparicio, C. Gallart, C. Chiosi, & G. Bertelli (ApJ, 469, L97 [1996]), there is an error in the legend to Figure 2. The information for panels C and D was interchanged in the legend. The correct information is given at the bottom

We obtain the time delay between the arrival time of the A and B images of the QSO 0957+561. The results of applying two different methods (the discrete cross-correlation function and the dispersion estimation technique) to the observed light curves of the A and B images are presented. The adopted value (time delay) is of Delta tau BA = 424 +/- 3

We have measured the brightness of the optical counterpart of the black hole X-ray binary Nova Sco 1994 (GRO J1655-40) during 40 nights between 1995 May 3 and July 27. From our observations and data from the literature we refine the orbital period to be 2.620 40+/-0.000 98 d. We model the R-band light curve as primarily arising from an X-ray heated