A year after Comet Hyakutake's surprise appearance, the world was greeted with another spectacular celestial treat: Hale-Bopp, the great comet of 1997. April 1 will be the 25th anniversary of Hale-Bopp's closest approach to the sun and the taking of this picture.
Hale-Bopp was discovered in July of 1995 by Alan Hale and Thomas Bopp by looking through telescopes with their eyes (a quaint old practice becoming less & less common these days). They each noticed a faint fuzzy object near globular cluster M70 and, after checking star charts, reported their discoveries to the Central Bureau for Astronomical Telegrams. Two years later, that faint fuzzy object was brighter than any star in the sky. Between its rise to brilliance and gradual fading, Hale-Bopp was visible to the naked eye for 18 months, longer than any comet in recorded history.
After being caught without a telescope for Hyakutake, I had bought a 'scope and mount with a clock drive, so I was able to make longer-exposure photos of this comet without the stars trailing. I took pictures of the comet every clear night leading up to its perihelion passage around the sun, but an unseasonal huge snowstorm arrived on March 31, the day before the big event. Here's the writeup I produced for prints of the comet back then:
Blizzard conditions—that was the weather as I started the Monday drive down to work in Greenwich, CT. The forecast was for clouds until Thursday, so I didn’t even think of bringing my telescope and camera. But by Tuesday afternoon the storm that had dumped two or three feet of snow in the Berkshires had headed out to sea, and the sky was crystal clear. Looking out the office windows at the blue expanse, I finally couldn’t stand it any longer and left work at 3 PM, setting out for home and the hills beyond.
The drive northwest of Springfield was a journey into surreal disaster. Heavy wet snow had snapped branches and limbs off virtually every tree. Sawed-off tree trunks lined the highway, branches dangled perilously from power lines, and damaged trees leaned precariously over the road. Towering pines were circled by wreaths of green branches torn from their upper reaches. I drove around looking for a good place to set up, starting out on some roads, then backing up when I realized they were impassable. I ended up where I’d taken pictures before, at the Littleville Dam boat landing. The parking lot was snowed in, but the road to the top of the dam had been plowed, and I set up the scope there. It was still bitterly cold and windy at the top of the big open field leading down to the lake, but it was very clear and dark enough. I shot pictures until 10 PM, then, frozen, hungry and feeling sick, I packed up, headed home, rested a bit, and drove back to Greenwich, arriving twelve hours after I left. A crazy day, but worth it: Although I photographed the comet several other times, the pictures from this night were the best ones I got.
This photo was taken just 22 hours after Hale-Bopp’s closest approach to the Sun. Two distinct tails are visible. The white tail consists of cometary dust released as the Sun melts the comet’s nucleus. It’s white because it shines by reflected sunlight, and the curvature is caused by the motion of the comet. The faint blue tail is ionized molecules blown rapidly away from the comet by pressure from sunlight and the solar wind. The blue color is from the emission lines of ionized carbon monoxide.
The photo was taken with a camera piggybacked to a telescope equipped with a clock drive, which follows the motion of the stars as the earth rotates. Without the drive, the comet and stars would appear as lines rather than points. The field of view measures about 10 by 15 degrees. The bright star in the lower left is Almaak (Gamma Andromeda), a 2nd magnitude star. Crossing the upper right corner is the trail left by a passing airplane; the pattern is caused by red and white strobes (flashing at slightly different rates) and unblinking wingtip lights.
Date: April 1, 1997 at 8:10 PM
Camera: Nikon FTn with Soligor 135mm f/2.8 lens
Exposure: 4 minutes at f/2.8
Film: Fuji Super G Plus 400
Location: Huntington, Massachusetts
Tech notes: I initially digitized the 25-year old color negatives with my Epson V500 flatbed scanner, but that scanner warps images enough to make image stacking infeasible. So I turned to a 24-year old Nikon LS-2000 film scanner that someone had given me and managed to get it working, SCSI interface 'n all. Wow, what a difference! MUCH sharper scans, and no image warping. The LS-2000 was operated using VueScan, and the digitized images were processed using Affinity Photo, DeepSkyStacker, PixInsight (for background flattening) and StarNet++ version 2 (for star removal)--with FastStone Image Viewer managing the collection of images.
