The night sky displays swirling astral images, rising and setting amid a sky of darkness. The beauty of the stars certainly captures the imaginations of many photographers. However, novices would ruin their pictures with swirling star trails. These trails are caused by the Earth’s rotation, so the stars appear to cross the sky at speeds too great for adequate film exposure. If only an apparatus were designed to take into account the earth’s rotation.
Enter the Barn Door. Created from only two planks of wood, a metal rod, some PVC pipe and the occasional epoxy, a properly working Barn Door will eliminate star trails and make it possible to photograph the sky. In theory, the Barn Door’s construction is simple and straightforward. A lovely day trip to Home Depot coupled with the relief of a traditional IHOP breakfast equated to gathering of supplies and spirit.
Two planks of wood are hinged together to make a wooden mouth. The jaws are propped up by a bent steel rod which, when twirled, raises the camera to a quarter degree per minute. This raising negates any effects the earth’s rotation has on the perspective of stars. With the camera mounted on the PVC pipe, on top of the Barn Door, we were ready to shoot. Or so we thought. What only experience can enlighten is the steel rod must be adequately fixed so if it is rotated it will not kick up; effectively ruining any chance the camera has at having a clear exposure. Sure, we were able to take some decent pictures, but none of them properly fulfilled the dream the Barn Door created. When the first night of shooting came to a failed ending, we pledged to correct the flaws.
After some thorough re-engineering, we were finally confident the Barn Door would be able to rise smoothly without shaking and ruining our pictures. We packed up our supplies — Barn Door, telescope, camera equipment — into an American truck. The truck pulled up to a dirt dark road. There were no lights, save for a few stars penetrating throughout the hazy atmosphere. We knew the spot was right for the job because the field looked like the last remains of a dead farm.
We set up shop, placing the tripod firmly into the soft earth. The Barn Door, newly upgraded with a sturdier steel rod was screwed atop the tripod. We located the North Star via the Big Dipper and prepared for astrophotography magic. Our first subject would be the famed binary stars, located in the handle of the Big Dipper.
A binary star is a star system consisting of two stars orbiting around their common center of mass. Without the Barn Door the binary star, when photographed, came out as two streaking parallel lines. With the Barn Door the binary star became more accurate; the streaking lines were curtailed immensely. We were able to cancel out the speedy rotation of the Earth. They proved to be the perfect litmus test for the level of the Barn Door’s success.
Unfortunately, that momentary instant of success was the only glimpse of good news we generated from this Barn Door. The entire process is a learning experience, and hopefully the pains of our shooting will help any amateurs who have aspirations of shooting the night sky. First of all, it is imperative the Barn Door’s steel rod is rotated continuously throughout the exposure time. This way, the camera is continuously adjusting for the Earth’s rotation. Although this piece of advice might seem elementary, we tried the more practical approach of rotating the rod 12 degrees every 5 seconds.
While this was easier for the person rotating the rod, the camera was not sufficiently moving. It was only after this failed that we decided a continual rotation would be best. It is also important the Barn Door be mounted sturdily on the tripod. The first tripod we used was pretty light. This resulted in many slight movements that interfered tremendously with the finished shot. After switching to a heavier tripod the shots became much more crisp. The weather should be considered when choosing your shooting date. Clear nights without clouds serve to display the night’s sky in all its glory.
Also, taking a picture during a new moon would also help the shot. Without the moon in the sky there is much less light pollution. On the subject of light pollution, make sure you take the time to find an out-of-town location. There’s a reason why the best place for astral observation in the United States is Arizona. We settled for traveling 20 to 30 minutes out of Madison to find a good, desolate field. Even with our thorough searching, we still were not pleased with the level of light pollution.
For aspiring photographers out there who wish to fulfill the potential of the night’s sky with their cameras, make sure you build a proper Barn Door. This device is the first step toward great success with your shots. When planning your photo shoot make sure to keep in mind the weather, the phase of the moon and the shooting location.
Before shooting, make sure to consult planetarium software — free on the Internet — to locate the specific astral bodies that are out on that particular night. In the end, proper planning for this project is the key to its success.
