... The Galactic low-mass X-ray binary GS 2023+338 was discovered during the burst on May 22, 1989 with the Japanise satellite Ginga (aka Galaxy). The flux reached 17 crabs (this unit of flux measurement is an bright X-ray source, Crab Nebula) at 10-35 keV. ... No other radio telescope worldwide carried out multi-frequency measurements. ... Upon 14 days the radio flux fell below the detection level at the RATAN-600 in relation to the decrease of the X-ray flux. ...

... Analysis of the b ehaviour of the parameters of Balmer and HeI I emission lines in the sp ectra of EU UMA has revealed ­ dips in the b ehavior of equivalent widths of the lines rep eatable with the orbital p erio d. Considering the dips as a result of eclipse of the most part of the accretion stream by the secondary we have improved the value of the orbital p erio d of 90.1441 ± 0.0007 min and estimated the inclination of the system as 70 ; ­ the radial velo city ...