Two bright binocular variable stars, that are easy to find in the summer sky, are EU Delphini and U Delphini.
EU Delphini is a semi-regular star, whose variability was first detected in 1895, by the Rev. T.E.Espin, who is best remember as one of the founding members of the Liverpool Astronomical Society. The details of the star’s variability were first determined in the early 1900s, and were later refined to an amplitude of 1.11 magnitudes and a period of 62.7 days.
As an added bonus, within the same field of view as EU Delphini, is U Delphini. U Delphini is an irregular star with an amplitude of between seven and eight, and an approximate range of 100 days.
Despite the apparently small amplitude of these stars, they still display enough variability to interest visual observers.
Below is a chart, which has been adapted from the BAA original.
