Abstract
The authors present shape and spin axis models for four asteroids: 54 Alexandra, 167 Urda, 409 Aspasia, and 1022 Olympiada. The models were constructed using a combination of dense lightcurves and sparse data sets from USNO observations for lightcurve inversion. The use of combined dense and sparse data sets in order to find asteroid models will become more common as nextgeneration large surveys come on line.