With growing experience you can follow several enticing stars throughout their entire range with standard 7 x 5 0 binoculars. These four stars are easy to find; just use the charts in Figs. 13.1, 13.2, and 13.3.

R Scuti

This most interesting bright variable ranges over about two magnitudes in almost five months. However, it shows many irregularities, and even its period, listed as 140 days, is not precise. Because the inspiring open cluster NGC6705 (M11) is nearby, R Scuti is as easy to find as it is fun to estimate. The range is large, it is well placed in the sky from May to September and is a fine example of an easily observed bright variable.

R Scuti is a special type of star, in the RV Tauri class. At first its light performance mimics Beta Lyrae, although the period is much, much longer and the maxima are sharper. But then the shallower of the two minima gradually deepens until it becomes the most pronounced low point, and the star now behaves more like a long period version of Delta Cephei. You should estimate R Scuti once each week.

X Herculis, g Herculis, and RR Coronae Borealis

These are semiregular variables that provide an interesting weekly project (Fig. 13.3). X Herculis is a semiregular red giant that seems to have been deliberately placed in the sky so that you would have an easy time finding and estimating it.