As mentioned in the Solar System section, webcams can be electronically modified to take long exposures. It's way beyond the scope of this chapter to explain what needs to be done, but suffice to say the job is an exacting one, demanding good soldering skills and a good knowledge of electronics. In the past, several companies offered "professionally" modified webcams. Recently, though, with the introduction of inexpensive integrating CCDcameras, these outfits seem to have disappeared. The Meade LPI (Plate 70) is still available, but it's not a good choice for deep sky imaging. No matter how long the exposure or how many frames are stacked, its CMOS chip is not sensitive enough to record even bright deep sky objects in detail.
A modified webcam is a cost effective way of getting into the deep sky game. However, the small chips that make webcams great for planetary imaging are a drawback for the deep sky. In deep sky picture taking, what's usually wanted is a relatively wide field, low magnification views of the sky. Long exposure webcam images also tend to be noisy, making them hard to process without heroic efforts. There is one type of webcam-like imager that can ease entry into the deep sky arena, the Meade DSI (see the section on CCD cameras). It operates much like a webcam, but is much more sensitive.
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