1912 Activity: Blink Comparator

Try this in order to appreciate Henrietta Leavitt’s many years of hard work in the plate stacks at Harvard College Observatory. Below are two simulated images of a star field taken six months apart. Can you tell which is the variable star? No? Well, try this activity to see how a blink comparator can help.

Below you will find the same two images, each on a separate page. Copy these images onto two separate documents, such as Microsoft Word. Open them both and line up the two windows on your computer screen. Then switch back and forth between the two quickly and watch for the one star that is bright enough to show up on one image, but is too dim to see on the other.

 Star Field Alpha — January 1, 2010    Star Field Alpha — June 1, 2010
Star Field Alpha — January 1, 2010   Star Field Alpha — June 1, 2010