These beacons, called masers (the radio equivalent of lasers) show up as bright spots in the radio images.
masers in the star-forming region W3(OH ).
The astrometric precision will also enable proper motion studies, and accurate comparisions of oh masers with methanol, water and other species.
Until now methanol masers have been found only in association with massive young stellar objects.
We have obtained 6 epochs of VLBA 22 GHz water maser data, monitoring the masers around the pulsating evolved star U Orionis.