A lighthouse on a rocky shore shines steadily until the wind carries smoke from the keeper's fire. The light fades before your eyes, even though the flame inside remains intact. That is roughly what happened on May 11, 2021, to a distant beacon in the constellation Centaurus: the star WR 59, which astronomers regarded as a model of constancy, dimmed by a factor of three within a few hours.
The first to notice was Australian observer Rod Stubbings. His 22-inch telescope, equipped with an eyepiece providing 270x magnification, allowed him to separate WR 59 from a bright neighbor located just 11 arcseconds away, roughly the width of a hair at arm's length. Automated sky surveys such as ASAS-SN or ATLAS blend the light of the two stars into a single blob, so they cannot tell that WR 59 itself had faded. The human eye at high magnification proved more precise than a robot.
Over the next 24 hours, Stubbings made seven brightness estimates and recorded a deep minimum. He then asked another observer, Stephen Howell, to confirm the dimming. Later, in 2026, he compared his records with archival data from the TESS space telescope, which happened to be looking at the same field in May 2021. The light curves matched: TESS also saw the dip, though shallower, because its detector mixed the light of both stars. However, the satellite filled 22.58 hours when Stubbings could not observe, and it revealed brief brightness fluctuations during the recovery.
Before this event, WR 59 was considered quiet. Now it is clear that it periodically hides behind its own smoke, like a lighthouse that blows out its own flame. The dimming was caused by a dust cloud ejected by the star and passing between it and Earth. Such clouds form in the dense wind when gas cools and carbon condenses into solid particles, similar to soot from a candle. Within a day the cloud obscured the star, then dispersed over two weeks.
Stubbings's work shows that an amateur telescope with a good eyepiece can still compete with space observatories when it comes to resolving close stellar pairs. He continues nightly observations of WR 59 and has already recorded ten more similar dimming events. Full data from these events will be published separately. For now, the beacon in Centaurus shines steadily again, but we know its smoke may return at any moment.
During the minimum, WR 59 became almost 3.3 times fainter than usual, but it would still remain invisible to the naked eye: at magnitude 15.2, it is 4000 times fainter than the faintest stars visible to the eye on a dark sky.