However, when the moon is between the telescope and the source of the cosmic rays, Dr Colin and his colleagues reckon that it will be possible to separate the two by looking at the edges of the shadows.
Interestingly, an April 18 paper in the journal Nature reported that upper limits for neutrinos measured from IceCube are low enough that gamma-ray bursts are unlikely to be the sole source of ultra-high energy cosmic rays.
Given that we absorb some 40 millirems from our food (bananas being a large source funnily enough) each year, living in Denver gives you 50 millirems from cosmic rays, this seems a sensible enough low limit.