Are there sky surveys that perform gamma-ray absorption spectroscopy? I was wondering if dark matter might absorb gamma radiation. I have done a simple Bohr-atom type calculation assuming a dark matter model of a bound state of a North and South magnetic monopole and found a Rydberg energy of about a MeV. I assume that the mass of the monopoles is 1 Tev; masses less than this limit have apparently been excluded by particle accelerator experiments (to a confidence of 95%). I also assume that the monopoles have the minimum magnetic charge.