Webcams are typically supplied with software to enable users to view and to capture 'moving' images. This software is often fairly basic and not really suited to astro work.

For a start, this software will not understand about modified webcams. Also, images are likely to be recorded in file formats other than AVI. The AVI format is prefered as will became clear below.

Most people use one of the Microsoft Windows operating systems, so as far as I am able, I have given information about software for use on Microsoft Windows systems. I use the Linux operating system and find it to be more reliable, stable, secure, easier to manage --- and it's FREE. I have therefore included information which might be of interest to other users of Linux.

K3CCDTools is perhaps the best known Microsoft Windows application for capturing astro images from webcams. This program does understand about SC modified webcams and has a lot of functions which relate specifically to astro work.

K3CCDTools can be used free for a trial period. A licence fee is required to obtain a key to enable long term usage. I have been unable to get K3CCDTools to run under wine/Linux. (see below)

wxAstroCapture can be used to capture images from SC modified webcams. This application is totally free and versions are available to run under Microsoft Windows and natively under 32 bit and 64 bit Linux (ie without the assistance of wine). The authors (Carsten Arnholm and Martin Burri) chose to develop this program using the free C++ library 'wxwidgets' which is available in both Microsoft Windows and Linux versions.

Having captured webcam images as AVI files, we need then to extract/select individual frames, align them, and stack them. There are several programs available for this purpose. I will refer to here only two.

Without doubt, the best of all is RegiStax. This is a Microsoft Windows application, but it can also be run under Linux with the aid of wine -- providing that captured AVI files are in RGB24 format. Details are given on the RegiStax website.

wxAstroCapture allows AVI files to be saved in RGB24 or YUV420 format.

wxAstroCapture plus RegiStax/wine, is a very workable solution for Linux users wishing to do astrophotography via webcams.

The other application that I will mention is AstroStack. AstroStack can be downloaded free, but a licence fee is payable to obtain the main function library. In my opinion, when compared with RegiStax, AstroStack is rather cumbersome to use. I mention AstroStack, because it's written in Java and so can be run on any computer on which the Java Run Time Environment has been installed.

After capturing, aligning, stacking, and producing a partially finished image, you will probably want to do final adjustments and printouts using normal image processing software. Some options for this are discussed in 'Image processing'.


Firmware Changes and Advanced Image Capture

Software which resides permanently within webcams and is responsible for them actually working is refered to as 'firmware'. It is possible to update and to modify this firmware, so as to for example make an old ToUcam respond as if it were an SPC900NC.

Sensor chips used in unmodified webcams are basically black and white sensitive, but are used to synthesise colour images via a system of coloured microlenses fitted in front of the sensors. It has been shown that captured images can be somewhat sharper if this system is bypassed.

The two topics mentioned above are really for advanced users and are not discussed further here. Readers who are interested will find information on these topics on some of the websites already refered to. (and at this stage, I am not qualified to discuss them)