So much in astronomy depends upon accurate distance
measurements to objects seen in the sky. The most accurate
methods involve measuring the motion of a star in the sky due to
the earth’s revolution around the sun and then calculating
geometrically the distance to that star. Unfortunately, as we study
more distant stars, this motion called parallax becomes tinier and
tinier until measuring it to any degree of precision becomes
impractical. It is this dilemma that leads us to seek other methods
of determining distances. Studying variable stars in stellar clusters
helps us to find distances to objects that might be otherwise
incalculable and is therefore vital to our improved understanding
of the universe.
As will be further explained later, clusters are an important place to
find variable stars as they consist of stars at a similar distance and
of similar age and composition. However, clusters may consist of
thousands of stars and searching for variable stars on an individual
basis proves tedious at times.