28 Aquilae (HR 7331, V1208 Aql) was first announced as a δ Scuti type variable by Breger in 1969 with a period of about 0.15 day. It was clear that the light variability could not be adequately represented as a sinusoidal variation with just one frequency. Since then several observers have provided additional light curves and new analyses of the light variation. In this paper we discuss observations which we have made and an analysis of the data available since 1966.
Our objective was to find the frequencies of components which would represent the light variation of 28 Aql over the 28 years for which the star has been observed.
Using the 30 cm reflector of the Hume Cronyn Memorial Observatory we observed 28 Aql in 1979, 1980, 1981, and 1993 in blue light. The light curves for JD 2444140 and 2449190 are shown below. Comparison stars were HD 180868 and HD 181383. Magnitude differences are referred to HD 181383. Nights on which the scatter in the observations, due to poor transparency, appeared to be excessive were discarded. Observations on 21 nights were retained for analysis.