RegiStax V3

RegiStax is free image processing software developed by a small international team led by Cor Berrevoets from the Netherlands. It's most commonly used by amateur astrophotographers and is written for Windows, although Linux users can run it through Wine. Its main purpose is to produce high quality enhanced images of astronomical observations by aligning and stacking a sequence of frames of the same object, usually taken from an AVI video of the Moon, the Sun or a planet. RegiStax 6 simplified the processing sequence by removing the separate Optimize and Final tabs, because the new alignment method optimizes directly. Version 6.1.0.8 from May 2011 is the final release, and the author now develops waveSharp, a separate tool based on the RegiStax wavelet sharpening.

One of the major components that enhance the speed at which the images are processed is multi-core support: RegiStax 6 can use up to 8 CPU cores during alignment and stacking. The interface has been simplified and made more uniform, which is always a plus for anyone getting into astronomy.

A useful technique is trapping noise, which is done by using Gaussian wavelets: the noise is kept in the first wavelet layer so it does not show up in the higher layers. Processing long video files is demanding, so a fast multi-core CPU helps RegiStax run at full speed.

It's free to use and helps amateur astrophotographers turn video frames of the Moon, Sun and planets into sharp images.

Another great feature RegiStax has is the renewed alignment module, which uses OpenCV alignment methods and places alignpoints on the image to track the details of the scene. The program also supports dark frames, flat fields and reference frames.

Processing runs in clear stages: Align, Stack and Wavelet, where post-processing functions such as rotation and cropping are also located, and an automatic processing option moves from one stage to the next. Overall, RegiStax is a good choice for any aspiring astrophotographer, or anyone who likes image stacking as a hobby.