Stratospheric aerosols were collected at Poker Flat, Alaska, in July 1979, to determine particle properties, confirm coincident satellite SAGE measurements, and compare similar results obtained with different airborne samplers. Because of the steep slopes in size-distribution curves for larger particles, we found properties such as concentration, aerosol mass, and optical extinction are very sensitive to small errors in radii. We calculate that our concentration measurements agree with photoelectric particle counter results when a 16% radius change in introduced. An 8% radius change matches our calculated sulfate mass with filter mass measurements. And a 13% radius change results in agreement between our calculated optical extinction and coincident SAGE satellite results. Recognizing that different instruments can produce 10--20% differences in measured sizes, we believe the results of these comparative measurements of SAGE and in situ instruments are essentially in agreement.