Dust envelopes in the peculiar objects CH Cygni and TX Canum Venaticorum

The photometry of CH Cyg and TX CVn in the UBVRJHKLMNQ system is presented. For CH Cyg, it was foUnd that the pise of the brightness of the hot emission soUrce+ which appeared in 1977, was accompanied by the increase of the circumstellar envelope flUx. The physical connection between these phenomena, that is, the inevitability of appreciable influence on the dust envelope luminosity of the hot emission source arising against the red giant background is substantiated. In its turn, the source of the additional UV emission should be a physical variable. Extension of the spectral range of the observations of TX CVn up to 10 mcm enables to confirm definitely the presence of the dust circumstellar envelope in this double system. Luminosity, average temperature and mass of the dust particles are approximately 1035 erg/s, approximately 600 K and approximately 10-8 Msub(Sun) respectively