We have constructed a multichannel photometer that allows observations of a variable star, a nearby comparison star and the sky background to be made simultaneously (Kozhevnikov & Zakharova 2000). A CCD system for automatic guiding is recently incorporated into the photometer. This system allows good centering of two stars in the photometer diaphragms during the whole observational night. Using several examples of observations from our operational experience, we demonstrate advantages of multichannel photometry in observations of rapid stellar oscillations and planetary transits. Observations of the intermediate polar V405 Aur with the multichannel photometer show the ability to suppress high-frequency noise in poor seeing, Observations of the intermediate polar V709 Cas show feasibility of detection of weak periodic signals from rather faint stars (14 mag) with semi-amplitudes up to 2 mmag, using relatively small telescopes (70 cm). The rms noise of the lightcurve of the planetary transit of HD 209458 is mainly limited by scintillation noise and equals 1.2 mmag.