Another Approach

Pennsylvania astro imager Gary Honis uses a different approach to image deep-sky objects with his Olympus C-2000 Z and C-2020 Z cameras and 20-inch Starmaster Dobsonian reflector, which is equipped with a tracking system. Although his cameras are limited to maximum exposure times of 32 and 16 seconds, respectively, his telescope’s large aperture can gather a lot of photons during such exposures before noise effects become a problem.

Imaging relatively bright deep-sky objects such as globular clusters is a piece of cake for Honis. "In fact, a single 16-second exposure is sometimes acceptable," he says. "For dim clusters, stacking several images can help improve the image. For dimmer galaxies or nebulae, the exposure limit becomes a problem, even with a large aperture. I need to stack multiple exposures to improve the results."

To assist in the camera’s cooling, Honis attached a small computer fan to his C-2000 Z camera. "This involved taking the camera housing apart, removing the tripod-mount socket to create an opening, and mounting a 12-volt DC fan over the opening to force air into the camera body," he explains. "The results are dramatic. Heat generated by the electronics is quickly pumped out of the camera. On freezing nights I can do practically noise-free, single-shot deep-sky imaging with a 2-megapixel $300 point-and-shoot digital camera in full color!"

Honis describes a complete, step-by-step procedure on how to disassemble a C-2000 Z on his Web site. He and other astroimagers are experimenting with adding thermoelectric cooling to the digital camera's CCD detector. Thermoelectric cooling systems are currently used in many astronomical CCD cameras.

Bear in mind that modifying your camera will void its warranty, so proceed at your own risk. Failure to take proper precautions can result in permanent damage to the camera’s sensitive electronics and/or optics. "After disassembly and reassembly my camera functioned properly, but your camera may not," warns Honis.

How deep can such an air-cooled camera setup go? "By stacking multiple exposures, the bright galaxies are not a problem," he says, "and I can crudely image very faint objects such as the Horsehead Nebula."