  We find convincing observational evidence to confirm the optical
identification of the X-ray burster X1746-370 located in the globular cluster
NGC6441. Chandra/HRC-I imaging yields a much improved X-ray position for the
source, which we show to be fully consistent with our rederived position of a
UV-excess star, U1, in the same astrometric reference frame. In addition, the
smaller Chandra X-ray error circle excludes the only other blue stars
previously identified in the old Einstein circle. We have also obtained Hubble
Space Telescope/STIS time-resolved optical spectra of star U1. Although there
are no strong line features, the flux distribution demonstrates U1 to be
unusually bright in the blue and faint in the red, consistent with earlier
WFPC2 photometry. More notably, the flux level of the continuum is seen to vary
significantly compared to stars of similar brightness. Indeed, the lightcurve
can plausibly be fit by a 5.73 hr period sinusoid, which is the period of the
recurring X-ray dips seen in this source. The presence of modulations in both
wavelengths strengthens the case for an orbital origin, and therefore deepens
the puzzle of the unusual energy independent X-ray dips. Lastly, we note that
X1746-370 remains the longest period confirmed X-ray burster in a globular
cluster, and the only one with a period typical of the galactic population as a
whole.
