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Webcam amateur astronomy

Computer and operating system
Driver software
Acquisition software
Data reduction
Theory and tests

Computer and operating system

You need a computer that you can connect the webcam to. It must have the right sort of port to plug the webcam into, usually USB, in rare cases the parallel port. Parallel ports are common on Intel and AMD PCs. USB is common on new PCs, both Intel-compatibles and Macintoshes. Most likely you need a laptop in order that you can easily carry it to where your telescope is.

Your computer also must run an operating system for which there is driver software to make your webcam work. The simplest way is to use some Microsoft operating system on an Intel-compatible CPU (Intel Pentium I/II/III/4, AMD Athlon, etc.), or presumably MacOS on a Macintosh. When choosing a varety of Windows, note that Windows 95 and Windows NT do not support USB, you need Windows 98 or Windows 2000 instead. I can't remember whether Windows 95 SE has USB support.

With both my webcams I was hoping to make them work on GNU/Linux, and very recently I have managed to do so for both. GNU/Linux is a free Unix-like operating system like the ones you may find on "real" computers (mainframes, Sun, SGI and HP work stations, etc.). You can put Linux on Pentiums or Athlons. The "Linux" part of GNU/Linux is the so-called kernel, a big chunk of software that binds to the hardware and in turn to which the user interface and applications bind.

Linux was started in 1991 by Linus Torvalds at the University of Helsinki. At that time the GNU Project had already a large body of application software, most famously the Emacs editor and the GCC software development suite. GNU stands for "GNU's Not Unix!", since 1984 they were working towards a Unix-like operating system. They never got there, because Linus filled in the large remaining gap with the Linux kernel.

GNU is also the Free Software Foundation (FSF), campaining for software to be free (similar to free speech, not like free beer). They have a definition at They have started this long before some big computer companies have jumped on the Open Source bandwagon, which is really a concession by big business to the argument FSF were making. FSF have drawn up the GNU General Public Licence, a software licence that is used by many programmers, it regulates all of the Linux kernel and all of the standard software of a GNU/Linux operating system. If you write software, you should consider using this to licence it. It allows you to make your software available without having to fear that someone will take your code and make big piles of money out of it. It protects the user as well as the author.

Finally, people talk about "Unix-like". NetBSD (another Unix-like operating system) have a little page about ducks and duck-like animals at Unix is a trademark and makers of Unix-like systems may or may not want to comply with the trademark owner's rules.

Linux laptop My laptop, running Linux and being guarded by Tux the penguin, who is the Linux mascot.

I earn my living with managing Unix-like operating systems, including Red Hat Linux. So, naturally I would like to do my astro webcam'ing under Linux, an environment I know well. Unix-like systems are by design and pedigree also a better operating systems than Windows, and Linux is as good as systems from hardware vendors such as Sun or HP.

Much as I would like to convince you to run GNU/Linux on your home computer, in my work I also have to make the computers do what the users want. In many cases it is just simpler and more efficient to use a Windows-based solution. It will not only be easier to use your webcam, it is also easier to use Windows. That's not because the user interface is better, but because there are plenty of people around who can help you out.

My computer is a Toshiba Satellite Pro 4600 laptop with a 15" 1024x768 pixel display, an Intel Pentium III 800 MHz CPU and 20 GByte disc space. The system is dual-boot, so that after switching it on I can choose to run Microsoft Windows 2000 or Red Hat 8.0 GNU/Linux as operating system. The Windows 2000 disc space is also visible from Linux so that the reduction software on Linux can use the data written on Windows.

To make life under Windows more bearable I have installed Cygwin. Cygwin runs on Windows and gives me a Linux style (or should that be Unix-like?) working environment, including command shell, editors and GCC software development tools.

Copyright © 2003 Horst Meyerdierks
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