During the ASTAR 2004 (Arctic Study of Aerosol and Radiation) campaign, conducted in Mai and June 2004 in the vicinity of Svalbard height dependent aerosol optical depth (AOD) in the spectral range from 350 nm to 1050 nm with an airborne Sun photometer were measured. The measurements were done on board of the aircraft behind a quartz window with well-known transmission. Observations were performed on board of the Alfred-Wegener-Institute research aircraft Polar 4 during 9 flights between the 14 Mai 2004 up to 3 June 2004 with the operation base Longyearbyen (78° 13′ N, 15° 38′ E). Based on the height dependent aerosol optical depth for four selected wavelengths (415 nm, 535 nm, 864 nm, 1025 nm) and the Ångström parameter Alpha (spectral slope) and Beta (AOD at 1000 nm) between 50 m and 7081 m the extinction coefficient (AOD per kilometer) can be calculated for selected wavelengths, for example for LIDAR or satellite comparison and validation. For special comparison is also the height angle of the Sun included.