PHOTOMETRY OF CH-CYGNI IN 1991-1994 - OPTICAL-ACTIVITY AGAINST A BACKGROUND OF REDUCED BRIGHTNESS

Based on the optical and IR photometry of CH Cyg performed between 199 1 and 1994 and our results published previously (Taranova and Yudin 19 92a, 1992b), we have established that in mid-1990 the hot source in th is system entered the next phase of its optical activity (outburst). T he outburst occurred at a reduced optical brightness of the star and w as observed through the circumstellar dust envelope that was formed in CH Cyg in 1985 - 1988 and had not been dispersed by mid-1994. Between 1992 and 1994, the system's red giant experienced temperature pulsati ons (Delta T approximate to 100 K) with a characteristic time of 500 - 600 days. In 1990, CH Cyg was obscured by a dust cloud that moved thr ough the circumstellar dust envelope with a velocity of similar to 0.7 R. day(-1) and had a diameter of similar to 300 R..