0420052

We propose to conduct extbf{fixed-time} observations for 2 uninterrupted INTEGRAL orbits (2 times 233 ks) of hard X-ray eclipse of the galactic microquasar SS433 at the maximum opening disk precessional phase centered on May 2 2007 11:30 GMT with the aim of confirming the unusual shape of theeclipse bottom first discovered by Ginga and suspected by previous INTEGRAL observations. This would allow as to put stringent constraints on the nature of hard X-ray emission region in SS433 discovered by INTEGRAL and to independently evaluate the binary system mass ratio which is a still unsolved controversy for this source. The proposal is not associated with the AO-4 Key Program. [truncated! Please see actual data for full text]