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A UVBY analysis of HR 8102 is presented. From recent data, a mean period of variation is found to be 0.097 d. A mean effective temperature of 7640 K and an average effective gravity computed over the pulsation cycle of 3.91 are derived over a pulsational cycle. The absolute visual magnitude is found to be 1.45m. These values suggest that HR 8102 is a normal Population I pulsating star and a member of the Delta Scuti group.

New photoelectric observations of the Delta Scuti star HR 5960 (CL Dra) obtained on nine closely spaced nights are discussed. It is noted that periodicities in the range of 0.06 d to 0.069 d have already been reported for this star. A Jurkevich periodogram analysis and nonlinear least-squares analysis give a primary period of 0.0676 d, with a secondary period of 0.0493 d. There is still some uncertainty whether the primary period is 0.0676 d or 0.0685 d. On the average, 55 observations of the variable were obtained each night, with an average interval of 5.5 minutes between observations. The air mass of the observations varied from 1.06 to 1.3. In all, 492 observations of the variable star were made.

Details are given on the design and performance of an extremely stable dc amplifier for use with photomultipliers in astronomical applications. Zero-level drift, a slight problem with most inexpensive high-gain dc amplifiers, is avoided with a new low-cost integrated circuit op-amp employing chopper stabilization. The output is read with a voltage-to-frequency converter with a nonlinearity of 0.03%, permitting larger than usual gain steps. Three gain steps cover the usual photocurrent range. Construction cost is approximately 50.

Four nights of photoelectric observations of the delta Scuti star HR 1225 have been obtained. The light curve has a variable amplitude envelope indicating that more than one period is present. A search for periodicities using the Jurkevich method and Fourier analysis suggests periods of 0.156 d and 0.097 d. A least-squares solution yields a fair fit to the data with these two periods. The Fourier transform suggests that three periods are present.

Differential photoelectric observations of three Delta Scuti stars AI Scl, WZ Scl, and XX Scl were obtained on ten nights during October 1978. Al Scl did not exhibit strictly periodic behavior, but showed a tendency to pulsate at 134 minutes. WZ Scl and XX Scl were both found to be multiperiodic, with period ratios of 0.6853 and 0.9522, respectively. As the period for radial fundamental and first overtone pulsation is 0.76, the observed period ratios are interpreted as caused by nonradial pulsation. A slightly modified Jurkevich period search method, used to obtain these results, is described.

The light curve of the star HD 200925 is investigated based on an analysis of published photoelectric observations. A preliminary search of the data for periodicities using the Jurkevich period search method indicates a period of 0.267 days, although the observations reported by Bedolla and Pe a (1979) for the night of September 26-27, 1978 are systematically brighter by about 0.08 magnitudes than the other observations. A nonlinear least squares fit of the values of the period, approximate amplitude (0.4 magnitude) and phase angle of the periodicity (0.9 radian) derived to a sinusoid is shown to differ significantly from the data obtained on the nights of September 24-25, 25-26 and 27-28, 1978, although confirming the period of 0.2672 days. Data also suggest the presence of a secondary period of 0.36 days, which, however, may rather be due to the asymmetry of the observed light curve.