Both spacecraft are involved in an extensive program of ultraviolet astronomy that allows them to study active galaxies, quasars and white dwarf stars in ways unlike any other spacecraft or telescope in existence. The light that Voyager is sensitive to has to be observed in outer space. Voyager's ultraviolet spectrometers are the only way scientists currently can observe celestial objects in a unique region in the short end of the ultraviolet portion of the electromagnetic spectrum. Thus the Voyagers are currently gathering data on early blue stars as well as other white dwarf stars nearing the end of their lifetime. Now that Voyager's primary mission of exploring the outer planets is over, there are fewer constraints on the science team when it comes to programming the spacecrafts' observations.
Stars can be very active, but also unpredictable.
We don't know when a star will do something. Voyager can now stare at an object for days and even weeks at a time to thoroughly map it and the region around it. Since the beginning of the interstellar mission, the Voyager project has been conducting a guest observer program which allows astronomers from around the world to make proposals and apply for time to use the Voyager ultraviolet spectrometer in much the same way that astronomers apply for time at ground-based observatories. This program enables scientists to make simultaneous observations of the same object using Voyager and ground-based telescopes. The cameras on the spacecraft have been turned off and the ultraviolet instrument is the only experiment on the scan platform that is still functioning.