AstroCrop is an application which automatically registers and precisely crops a series of images based on a single reference frame. It can be used to automatically crop a series of images or be used as an image stabilisation tool whose data can be easily processed by other stacking applications.
AstroCrop is currently available for Microsoft Windows and 64-bit Linux distributions.
A static tripod can be used to hold a DSLR with a long lens or a Bridge camera with high optical Zoom for capturing images of the Moon or Sun (suitably solar filtered.) This allows for very quick setup for imaging.
This simple setup can be used to capture a large number of frames but the nature of the static tripod can introduce significant movement between frames. Often, this movement is too great for stacking applications to successfully align the resulting image data. In addition to this, there is sometimes a disproportional amount of space between the object and the edge of the frame.
AstroCrop solves this problem by automatically finding the object of interest and cropping out the unneeded information. This is done by selecting a single reference frame and specifying a crop area. The application then automatically processes the data set and crops all images to match the reference frame. The outputted data are cropped and registers ready to be stacked in any stacking application. Similar problems arise when afocal images are captured of solar system objects using manually tracked mounts.
By using AstroCrop to precisely crop the images, the problem of significant object movement between images is solved.
AstroCrop can be downloaded by clicking here.
The following is a quick tutorial on how to use AstroCrop to process a series of images which have extreme movement between frames. It would be very difficult to stack images like these, particularly if there was a lot of them. AstroCrop is able to register each image and align them ready for processing in other stacking applications.