Figure:
The partially completed Sub-Millimeter Array (SMA)
on Mauna Kea, Hawaii. The SMA is a collaborative project of
Smithsonian Astrophysical Observatory and the Institute of Astronomy
and Astrophysics of the Academia Sinica of Taiwan (Moran 1998). The
SMA has been used to monitor Sgr A* at high frequencies as described
in the invited article in this issue (see Article by Jun-Hui Zhao).