A Direct Measurement of Atmospheric Dispersion in N-band Spectra: Implications for Mid-IR Systems on ELTs A. J. Skemer, P. M. Hinz, W. F. Hoffmann, L. M. Close, S. Kendrew, R. J. Mathar, R. Stuik, T. P. Greene, C. E. Woodward and M. S. Kelley Published online: 24 February 2010 DOI: 10.1051/ao4elt/201005019