In the present work, we study correlations between stellar fundamental parameters and the oscillation amplitude for delta Scuti stars. We present this study for a sample of 17 selected delta Scutis belonging to 5 young open clusters. Taking advantage of properties of delta Scutis in clusters, we correct the photometric parameters of our objects for

We present optical photometry and spectroscopy of the X-ray transient XTE J1859+226, obtained during outburst and its subsequent decay to quiescence. Both the X-ray and optical properties are very similar to those of well-studied black hole soft X-ray transients. We have detected three mini-outbursts, when XTE J1859+226 was approaching quiescence

We present UBVRI light curves of BL Lacertae from May 2000 to January 2001, obtained by 24 telescopes in 11 countries. More than 15 000 observations were performed in that period, which was the extension of the Whole Earth Blazar Telescope (WEBT) campaign originally planned for July-August 2000. The exceptional sampling reached allows one to follow

We study the far-infrared emission properties of the nearby starburst galaxy NGC 253 based on IRAS maps and an ISOPHOT map at 180 μm. Based on the analysis of the light profiles, we have been able to identify three main structural components: an unresolved nuclear component, an exponential disk, and a kiloparsec-scale bar. In addition, we also

Observations of the optical counterpart to XTE J1650-500 with the Magellan 1 telescope find it fainter than expected based on reports of it's possible detection on the DDS2 red (Groot etal IAUC 7708) and blue (Castro-Tirado etal IAUC 7707) plates. The observations were made with the Sackler MagIC CCD camera in non-photometric conditions on 03 Aug

From a comparison of the different parameters of warped galaxies in the radio, and especially in the visible, we find that: a) No large galaxy (large mass or radius) has been found to have high amplitude in the warp, and there is no correlation of size/mass with the degree of asymmetry of the warp. b) The disc density and the ratio of dark to