The following images compare pictures of Hale-Bopp with images of the same field from the digitized sky survey. The digitized sky survey images were taken decades ago, long before Hale-Bopp had been discovered.
On the left are images from the digitzed sky survey. On the right are images of Hale-Bopp.
The bright star in each Hale-Bopp image has been dubbed by many as a "companion" to Hale-Bopp, dubbed by many as the "Saturn Like Object" or SLO. By comparing the two images, you can see that the SLO matches exactly with the brightest star in the digitzed sky survey image. Thus either the object is a star, or the "companion" only appears to occult the brightest star in the field.
The right image was taken by Chuck Schramek on November 14 and is the original SLO image. The star has been identified as SAO 141894.
Image on right taken by Fukushima and N. Yamamoto of the National Astronomical Observatory of Japan on April 20, 1996. The star has been identified as SAO162944.
For a more thorough explanation, check out the HaleBopp homepage and University of Hawaii