  Most asteroids are somewhat elongated and have non-zero lightcurve
amplitudes. Such asteroids can be detected in large-scale sky surveys even if
their mean magnitudes are fainter than the stated sensitivity limits. We
explore the detection of elongated asteroids under a set of idealized but
useful approximations. We find that objects up to 1 magnitude fainter than a
survey's sensitivity limit are likely to be detected, and that the effect is
most pronounced for asteroids with lightcurve amplitudes 0.1-0.4 mag.This
imposes a bias on the derived size and shape distributions of the population
that must be properly accounted for.
