At 18:10 Universal Time(UT) on June 14, 1992, a nondescript 9th-magnitude star in Cetus had already started to fade. Within 21 minutes it lost half its normal luster, but then in the next two hours it almost fully recovered. Astronomers were not expecting this behavior. In fact, no one saw it at all!

Despite the fact that this star lies just one binocular field west of the renowned variable star Mira, no Earthbound eyes were turned its way. The unusual fading was noticed years later, as scientists sifted through the many gigabytes of data transmitted back to Earth by the European Space Agency's Hipparcos satellite.

As Hipparcos project scientist Michael Perryman explained, more than 8,000 stars previously believed to be constant were found in the satellite's data to vary. Of these, 3,000 received official designations in time to be labeled in the Millennium Star Atlas, even though astronomers knew very little about them yet (and still don't). Their secrets are waiting to be unlocked by diligent observers with small backyard telescopes.

In the article "Mining Hipparcos’s Buried Treasure," Sky & Telescope presented a list of some of Hipparcos's "unsolved variables." Here is another. The 11 stars summarized in the table on page 5 are well placed for viewing from various parts of the world on November and December evenings. The finder charts on these pages are just what observers need to detect the occasional dips in light that we already know take place.