  During the last two years we have used the Palomar Testbed Interferometer to
observe several explosive variable stars, including V838 Monocerotis, V1663
Aquilae and recently RS Ophiuchi. We observed V838 Monocerotis approximately 34
months after its eruption, and were able to resolve the ejecta. Observations of
V1663 Aql were obtained starting 9 days after peak brightness and continued for
10 days. We were able to resolve the milliarcsecond-scale emission and follow
the expansion of the nova photosphere. When combined with radial-velocity
information, these observations can be used to infer the distance to the nova.
Finally we have resolved the recurrent nova RS Oph and can draw some
preliminary conclusions regarding the emission morphology.
