We measured the transition energies of the 1s-2p Kα transitions in Al4+ through Al11+. The aluminum ions were created and trapped using the LLNL’s Electron Beam Ion Trap (EBIT). Once created and trapped, upper levels were collisionally excited by electrons in EBIT\u27s electron beam. X-ray emission following radiative decay of excited levels was detected using the EBIT Calorimeter Spectrometer (ECS). We have measured the centroids of the strongest lines to an accuracy of less than 1 eV. These results will be used to properly identify line emission from celestial x-ray sources, such as elliptical galaxy NGC 4472 and black hole candidate Cyg X1, where x-ray emission from aluminum has been hypothesized. These results will be especially useful after the upcoming launch of the AstroH X-ray observatory in late 2015. Owing to its large collection area and relatively high resolving power, the Soft X-ray Spectrometer (SXS) calorimeter instrument on board Astro-H will, for the first time
