Another Inventive Nova-Hunting Method

Other hunters are inventing novel ways to find new stars. Take, for instance, the independent discovery of Nova Cygni 2001 No. 2 (V2275 Cygni) last August 18th by Kazuya Hatayama of Niigata, Japan. Like that of other photographic nova discoverers, Hatayama's equipment is quite simple: a 35-mm camera and a 100-mm f/3.5-5.6 lens. His search methods are also simple. He divides the Milky Way into 85 search areas. Each clear night he shoots 12 of these areas, making two exposures of each region — enough to fill a roll of 24-exposure Fuji Superia 400 film. Each 1-minute-long exposure reaches to about 10th magnitude; the faintest stars recorded vary with atmospheric conditions and light pollution.

Hatayama takes the exposed roll to a photo lab in the morning and picks it up at night, during which he scans the negatives for new stars. "Since I do not have many clear nights," he says, "I have the time to search." What's different about Hatayama's technique, however, is that he doesn't use a blink comparator. He visually scans the negatives in an ingenious way. The first step involves creating a photographic record of the 85 search areas. He selects the best negative of the two exposures he has taken of each area, each selected image becoming part of his growing archive. When he photographs an area again on a later date, he takes the better of the two new exposures, overlays it on the light table with an archived negative, and then shifts the negatives so that the images are ever so slightly out of alignment. Using a loupe, he analyzes each pair of negatives. Since every star should now appear double, Hatayama simply searches for a single star — a new star. "What makes this search method so remarkable," says Shigemi Numazawa, a fellow amateur from Niigata, "is that it is completely simple. It proves you do not need expensive equipment to make a discovery."

The importance of taking two exposures of each field each night was made evident the night of Hatayama's discovery. The first negative of the field that had the nova in it was poorly guided and no good. He discovered the nova on the second negative, which he overlaid on an image from his archive taken nearly a year earlier. "Understand," Hatayama says, "I was number two. So it's just an independent discovery." Yes, that's true. But, in a sense, Hatayama did make a discovery. For the first time in more than four years of searching, he realized that his method works.

Despite differences in techniques and approach, successful nova hunters all share the same overriding virtue: perseverance. Nova hunters are a dedicated group who demonstrate infinite patience. Discoveries come, but many hunters spend years, even decades, before they uncover a new star they can claim as their own. Still, regardless of the slim number of "new stars" out there, any amateur armed with only determination and a camera or a pair of binoculars can be the next great nova hunter.