RXTE observations of GRS1915+105

We report on extensive X-ray observations of the galactic superluminal motion source GRS 1915+105 with the RXTE satellite over the last year. More than 130 RXTE pointings have been performed on roughly a weekly basis. GRS 1915+105 displays drastic X-ray intensity variations on a variety of time scales ranging from sub-seconds to days. In general, the intensity changes are accompanied by spectral changes on the same timescale. Three types of bursts with typical durations between 10-100 sec have been identified which have drastically different spectral properties and seem to occur in a fixed sequence. One of the most intense bursts has a bolometric X-ray luminosity of approximate to 5x10(39) erg/s during the 25 sec maximum-intensity part.