The Big and Little Dippers are not constellations in their own right, they are groupings of stars that form a pattern called an asterism. The Big Dipper is actually part of the constellation of Ursa Major. The Little Dipper is part of the constellation of Ursa Minor. The next step up in the astrophotography learning curve is going from shooting short exposures on a fixed tripod to shooting longer exposures with a tracking mount. The tracking mount will compensate for the Earth's rotation. This will allow you to shoot much longer exposures without trailing, and to record much fainter stars. Using a barn-door tracker is fairly simple. The most important thing is aiming the axis of the hinge as close to the celestial pole as possible. Luckily it is near Polaris, so it's easy to find. The rest of the procedure is relatively easy and very similar to using a camera on a fixed tripod. You focus the camera, determine the correct exposure, open the shutter, and turn the drive bolt at one rotation per minute for the length of the exposure. The image at the top of this page was made with a Canon 1000D (Digital Rebel XS) and its kit 18-55mm f/3.5 - 5.6 Image Stabilized (IS) zoom lens. The IS function was turned off. It won't work for astrophotography. The barn-door tracker was driven by hand. A single frame was taken as an in-camera JPEG image with an exposure of 4 minutes at ISO 400 at f/3.5 with a fog filter at 20mm of focal length at 40F with in-camera noise reduction turned off. At this temperature, the camera has little noise. In-camera contrast was increased, and in-camera sharpening was at its lowest setting. A custom color balance was set in the camera on the sky background from a test exposure. The photo was made from a reasonably dark-sky location where the Milky Way was visible to the unaided eye. In post processing after the image was taken, the contrast was increased a bit, the color adjusted slightly, and the stars were sharpened a little bit. Image Data
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