In the April column, I mentioned that the variable star R Leonis is an excellent spring target for binoculars. It’s fun to track the star’s brightness as it cycles from maximum brightness to minimum, and back again. Visually estimating the magnitude of a variable star is not as difficult as it may sound. In fact, amateurs can successfully estimate the fluctuating intensity of a variable to an accuracy of one-tenth of a magnitude by comparing it to neighboring stars of known brightness.
Phil Harrington binocular universe (April 2007 online extra)
Take a binocular tour of R Leonis' neighborhood.