Navy Precision Optical Interferometer (NPOI)
From the highest angular resolution Ha observations to date, NPOI found the Be stars g Cas and f Per to have circum-stellar emission consistent with a Gaussian intensity distribution rather than a uniform disk or ring-like structure.
In 2002, NPOI accomplished the first 6-telescope image by O/IR interferometry, producing an image of the triple system h Vir.
NPOI observations show that Vega is a pole-on rapid rotator spinning at 93% of its breakup speed, with more than 2400 K difference in temp-erature from pole to equator. The temperature variation accounts for Vega’s near-IR excess and explains why no single atmospheric model accounts for its spectrum.