The data allowed Hudson et al. to produce a three-dimensional model of the object.
From August 19 to 22 of 1989, Hudson and Steven Ostro observed asteroid 4769 Castalia from the Arecibo Observatory, producing the first direct image of an asteroid.
Helin discovered or co-discovered 872 asteroids, including the first two Aten asteroids: 2062 Aten and 2100 Ra-Shalom; the Apollo asteroids 4660 Nereus, 4769 Castalia and others; various Amor asteroids; three Trojan asteroids including 3240 Laocoon; and 9969 Braille.