Processing Techniques

The steps that turn calibrated, stacked exposures into a finished image — stretching the very high dynamic range so faint nebulosity and bright cores both show, balancing colour, reducing noise, and sharpening detail. Done honestly it reveals what the data contain; the goal is to represent real signal, not to invent it.

The reference exposures that remove a camera's own signature from an image: bias frames capture the sensor's read pedestal, dark frames the thermal signal that builds up during an exposure, and flat frames the uneven illumination and dust shadows of the optics. Subtracting and dividing by these calibration frames turns raw data into a faithful record of the sky.

A technique for combining many dithered exposures that recovers resolution lost to undersampling, by mapping each input pixel onto a finer output grid. Developed for the Hubble Space Telescope's deep fields, drizzling is now widely used in both professional and amateur imaging to sharpen stacks of slightly shifted frames.

Identifying exactly where an image points by matching the pattern of stars it contains against a reference catalogue, and so assigning precise celestial coordinates to every pixel. Plate solving lets software centre a target automatically, sync a mount's pointing, and stamp images with an accurate coordinate solution.