More than 20 years ago Comet Hyakutake graced the skies of Earth, passing closer than any other comet had passed in 200 years. It was a spectacular sight, made even better because it appeared to pass through the handle of the Big Dipper. This photo, taken by Glen Gould and stitched together by me, is the result of quest that took persistence and creativity.
Seattle is not a very reliable place to see stellar events and March 1996 was typically cloudy. We knew we had to travel somewhere to photograph the comet. But where? Many of our usual viewing sites in eastern Washington were covered in snow, so we decided to head to Othello. To our surprise, there was as much light pollution in this sparsely populated area as in a big city. Each small farm had two to three unshielded mercury vapor lights perched on tall poles. Light lessens the ability to see the stars and makes it impossible to capture a comet on film.
Defeated, we spent the night in a hotel and set off to eastern Oregon the next morning, hoping that the rain shadow of Mt. Hood would be clear and dark. That night we found a small spot by a river to pitch our tent. Soon after, light clouds started to gather but our hope did not wane. We set an hourly alarm so we could jump out of the tent and assess the sky throughout the night. No luck. By the morning snow started falling. Disappointed, we headed back to Seattle.
After arriving home around 2:00 PM, we decided to look at the national weather map to find a place with clear skies. We chose Las Vegas. That might sound strange given the vast amount of light pollution, but we know the area outside Las Vegas well. The desert is deserted and there are enough mountains around that is it possible to mask the glow of Las Vegas lights. Besides, there are not many places where there are frequent flights and seats available on short notice. We packed up the camera equipment and headed to the airport.
At the ticket counter we explained our desperate need to get to Las Vegas. The agent assumed we were eloping, took pity, and got us the last two seats on the plane. Fortunately all this happened in the pre 9-11 days, as the apparatus needed to photograph the comet would never have gotten through security.
Photographing stars and comets requires a long exposure. The Earth is constantly rotating, so it is necessary to compensate by using a device called a star tracker. The tracker moves the camera to match the rotation of the Earth. The photo will then capture stars as pinpoints and not as smears of light.
We didn’t have the money to buy a motorized star tracker, so Glen built a manual one. He used a very large barn door hinge, a paint stick, a small LED clock, the numbered part of a mechanical kitchen timer, a small battery-operated gooseneck lamp with a red filter, a straw, and some assorted screws. The camera gets mounted on the hinge. The paint stick becomes a crank. The numbers on the timer guide the manual turning of the crank. The turning rate is monitored using the LED stopwatch and the lamp. Turning the crank causes the hinge to open, thus changing the angle of the camera. With a steady hand, it is possible to match the rotational speed of the Earth. (Build your own, see these instructions.)
We arrived in Las Vegas at 10 PM, rented a car, and drove north for an hour an a half. Then we pulled to the side of the road and set up the apparatus. Glen positioned himself on the ground in cranking position and I stayed on the lookout for the occasional car. Each exposure took up to 10 minutes. When I announced a car in the distance, Glen put a black card in front of the lens until the car passed. All the while he would continue to crank the apparatus.
It turned out to be an beautiful night and the end to an amazing cosmic adventure.