  Muon neutrino astronomy is drown within a polluted atmospheric neutrino
noise. However at 24 GeV energy atmospheric muon neutrinos, while rising
vertically along the terrestrial diameter, should disappear (or be severely
depleted) while converting into tau flavor: any rarest vertical 12 GeV muon
track at South Pole Deep Core volume, pointing back to North Pole, might be
tracing mostly a noise-free astrophysical signal. The corresponding Deep Core
6-7-8-9 channels trigger maybe point in those directions and inside that energy
range without much background. Deep Core detector at South Pole, may scan at
18-27GeV energy windows, into a narrow vertical cone for a novel neutrino
astronomy almost noise-free, pointing back toward the North Pole.Unfortunately
muon at 12 GeV trace their arrival direction mostly spread around an unique
string in a zenith-cone solid angle. To achieve also an azimuth angular
resolution a two string detection at once is needed. The doubling of the Deep
Core string number, (two new arrays of six string each, achieving an average
detection distance of 36.5 m), is desirable, leading to a larger Deep Core
detection mass (more than double) and a sharper zenith and azimuth angular
resolution by two-string vertical axis detection. Such an improvement may show
a noise free (at least factor ten) muon neutrino astronomy. This enhancement
may also be a crucial probe of a peculiar anisotropy foreseen for atmospheric
anti-muon, in CPT violated physics versus conserved one, following a hint by
recent Minos results.
