In 1995, Tholen obtained images of the then newly discovered comet Hale-Bopp at a time when the comet was moving very slowly with respect to the background stars, thus permitting the red- green- and blue-filtered images to be combined into a color composite without the background stars appearing as separately colored dots.
Later, then postdoc at University of Hawaiʻi, Olivier R. Hainaut discovered that a nearly identical image was being discussed by late-night radio host Art Bell and one of his guests, Courtney Brown, who claimed that it proved the existence of an unnatural object following the comet, something supposedly seen by those who had learned how to engage in the technique of "remote viewing".
Nevertheless, some conspiracy theorists maintained that Brown's version was actually the original image and that Tholen had removed the additional object from the one on the Institute's web site.
The Heaven's Gate cult was so convinced that the additional object was a spaceship coming to take them away from Earth that they committed mass suicide.
[3] David Tholen and Roy Tucker, co-discovers of 99942 Apophis, are both fans of the TV series Stargate SG-1, which influenced the naming of the asteroid.