RTT150 . Russian-Turkish 1.5-m Telescope . ... Telescope has two main foci (Cassegrain and Coude ) and allows to use six optical systems based on Ritchey-Chretien system with a common main mirror . At present scientific observations are being performed at the Cassegrain focus in main optical scheme with focal ratio of 1:7.7. ... flat . ... To use the Coude focus the removable flat diagonal mirror is also needed in the crossing point of declination axis and main optical axis of telescope. ...

Lack of co oling flow clusters at z 0.5 A. Vikhlinin1,2 , R. Burenin2 , W. R. Forman1 , C. Jones1 , A. Hornstrup3 , S. S. Murray1, and H. Quintana4 1 2 3 4 Harvard-Smithsonian ... Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile The goal of this work is to study the incidence rate of co oling flows in the high redshift clusters using Chandra observations of z 0.5 ob jects from a new large, ... Fig. ... Lack of "cooling flow" clusters at z > 0.5 3 Fig. ...