Since a cheap webcam doesn't have a tape or disk recording system, a PC or Macintosh is required to save the data captured by the camera. The processing power of the computer is not overly important, as webcam image capture software is pretty simple and undemanding. What is needed is plenty of hard drive space. Webcams don't produce single frames; they produce streams of video, usually in .avi fomat. A 90-second image sequence will require around 100 to 200 megabytes of storage. Thankfully, hard drives are cheap these days. If it's not possible to fit an older computer with a new drive large enough to accommodate big .avi files, it is possible to buy inexpensive external drives that hook to the computer via a USB connection. Unlike normal webcams, the Meade LPI doesn't require tons of drive space. It can automatically combine hundreds of frames without saving them as a big .avi file first.
Non-astronomy webcams come with the programs and "drivers" needed to capture video sequences, and the included software could be used for planetary imaging, but it's not designed with astronomy in mind and lacks things like focus indicators that astro-imagers need. What's recommended for astro-webcammers is the program K3CCD Tools (Appendix 1). K3CCD is available in both freeware and inexpensive ($50) versions, and contains everything the planetary imager could want. K3CCDuses the drivers provided by the webcam manufacturer but replaces the application software that came with the webcam. If possible, just install the drivers and leave the webcam maker's application software off to save disk space.
Finished .avi sequences are just the start of the planetary imaging process, since the goal of most Solar System astrophotographers is high resolution "stills." To achieve that, thousands of video frames must be combined into a single picture, and that picture must be adjusted to bring out maximum detail. One program has revolutionized planetary imaging: Registax. This freeware application amazed both amateur and professional astronomers when it was first released in the 1990s. It did the seemingly impossible task of allowing a webcam and C8 to produce pictures that were considerably better than most planetary images produced by professional ground-based telescopes. Registax, now in Version 4, is still working wonders today, is still free, and is still indispensable for Solar System imagers. See Appendix 2 for information on downloading this revolutionary astro-soft.
Unfortunately for Macintosh users, Registax is Windows only. So is K3CCD Tools. Luckily there's a pair of very good alternatives. Keith's Image Stacker for OSX Macs is similar in capability to Registax, and Keith (Keith Wiley) has camera control and image acquisition covered as well with his excellent Keith's Astroimager, which is just as nice as K3CCD Tools. Both these Mac apps are freeware.
Despite the fact that Registax contains some impressive image processing tools, it's still good to have a dedicated photo-processing program on hand for final tweaks. The "king" of these programs is Adobe Photoshop, which can do anything imaginable to images, from sharpening them to blurring them. Its high price (over $700) and giant feature set are probably overkill for the average webcam imager, though. A good and relatively inexpensive alternative is Corel's Paint Shop Pro ($100). This time-tested program will do almost anything Photoshop will, and will sometimes do it more quickly and easily.
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