B-band measurements of 3C 273 over some 110 years are compiled and used in a search for periodicities using the Jurkevich method. Periods of 2.0,13.65±0.20
The δ Scuti star ctalogue is used to derive the observational locations of such stars on the HR diagram.The theoretical and observational instability strips ar
We present multi-frequency, high resolution, radio structures of NRAO150 with VLBA and EVN array respectively, both of which show a very collimatedone-sided jet
Appearing in the composite spectral data of BATSE, EGRET and COMPTEL for GRB 910503, there is a bump at around 1600keV. We perform a statistical analysis on the
Near-infrared images and K-band spectroscopy of the massive starforming region IRAS 23151+5912 are presented.The JHK' images reveal an embedded infrared clu
We present a brief review of predictions of solar cycle maximum ampli-tude with a lead time of 2 years or more. It is pointed out that a precise predictionof th