Despite decades-old predictions of the expected presence of dozens of
cataclysmic variables in the cores of globular clusters, the number of
irrefutable, out-bursting candidates is still barely a handful. Using
multi-wavelength, multi-epoch HST images we have produced outburst and
quiescence light curves for the recently discovered large amplitude variable
CV1 in the core of the post core-collapse globular cluster M15. The light
curves and blue colors show that the object is a bona fide dwarf nova, with
absolute magnitude at maximum light rivaling that of the most luminous known
dwarf novae.Comment: 17 pages, 5 figures. Submitted to A